TMAO and heavy hydrogen

May 2, 2026May 4, 2026 gettingwell4 4-5 stars Advanced knowledge, Acetylcholine, Epigenetics, Neurochemicals, Stress DNA methylation

A 2026 review subject was possible involvement of deuterium in TMAO levels, which contrasted with the usual TMAO meme. I’ll curate this paper through an outline of its sections:

“The human gut microbiome plays many essential roles, but an often-overlooked role is to maintain an abundant supply of deuterium depleted (deupleted) nutrients to fuel the host mitochondria. Excess deuterium (heavy hydrogen) damages mitochondrial ATP synthase nanomotors, leading to a decrease in matrix water production with increased reactive oxygen species (ROS) and inefficient ATP production. A microbial metabolite, trimethylamine N-oxide (TMAO) is a powerful signaling molecule whose plasma levels are high in association with many chronic diseases.

In this paper, we present a hypothesis that TMAO is a marker for deuterium overload in the methylation pathway, in addition to its role as an indicator of a disrupted gut microbiome. The original study that brought attention to TMAO involved feeding mice synthetic choline with fully deuterated methyl groups. Fully deuterated TMAO was subsequently detected in the plasma. By contrast, a diet rich in eggs, a natural source of choline (a precursor to TMAO), does not raise TMAO levels. Many of the pathologies that are linked to elevated TMAO can also be viewed as strategies to promote the supply of deupleted water to the mitochondria, systemically.

1. Introduction – DNA and histone methylation regulate epigenetic modifications and imprinting. Phosphatidylcholine is a precursor to acetylcholine, an excitatory neurotransmitter in the brain. Trimethylated lysine molecules, recovered during protein metabolism, are precursors to L-carnitine, which facilitates the transport of fatty acids into the mitochondria to be oxidized for fuel production. Dietary phosphatidylcholine and dietary L-carnitine, in addition to endogenous sources, are important nutrients that provide methyl groups to the methylation cycle. Choline and L-carnitine, as well as a close relative, betaine (trimethylglycine), are all precursors to trimethylamine (TMA), a small methylated amine produced through microbial enzymatic action. Obligate anaerobic hydrogen-dependent archaea called methylotrophs in the gut can reduce the three methyl groups in TMA to methane gas.

2. Evidence that deuterium disrupts mitochondrial function – Deuterium (²H) is a heavy isotope of protium (¹H; hydrogen), and it is pervasive in nature, found in seawater at a concentration of 155 parts per million (ppm) relative to protium. Deuterium is highly damaging to the F₁F₀-ATP synthase (ATPase) nanomotors in the mitochondria that produce ATP, the primary fuel source of the cell. Deuterium loading suppresses the activity of many fundamental biologically important hydrolytic enzymes that depend on proton tunneling. It is likely that deuterium increases the frequency of unrepaired nuclear DNA mutations, by suppressing the activity of deuterium-sensitive repair enzymes.

The inherent collective proton tunneling (ICPT) process, which uses membrane-bound ATPase nanomotors in living organisms, is nature’s ultimate tool for discriminating hydrogen isotopes. This is because a deuteron (²H) cannot replace a proton (¹H) in its tunnel protein during enzymatic transmembrane transport due to its doubled mass and twice larger atomic nuclear size. The result is large compartmental, inter- and intramolecular deuterium disequilibrium in ²H/¹H ratios in all biomolecules, which readily distinguishes respiration from aerobic fermentation with adaptive significance. Deuterons irreversibly clog single proton tunneling ATP synthase nanomotors in mitochondria, resulting in the complete breakdown of ICPT.

This initiates many disease-causing molecular crowding mechanisms, which we review herein from the perspective of prokaryotic proton pumping and H₂ gas formation in the organic molecular realm of mitochondrial proton-donating substrates. Understanding at the systems level how humans protect mitochondrial ICPT processes and ATP synthase is a fascinating journey reviewed herein. We hypothesize that the process uses TMAO as the microbial stepping stone, employing deuterium discrimination to become an active player in forming the biological reaction.

2.1 Quantum tunneling and proton-coupled electron transport – ICPT is a theoretical quantum mechanical phenomenon proposing that a single proton spontaneously passes through a potential energy barrier, typically within a hydrogen bond, in a manner that can be functionally irreversible. Unlike classical particles that must surmount energy barriers, protons can ‘tunnel’ through them due to their wave-like nature. Often, this single proton tunneling is part of a larger process where a proton and an electron are transferred simultaneously (or sequentially) as a single kinetic step, often in the presence of strong electric fields that stabilize the transferred state. This process is referred to as ‘proton-coupled electron transport’ (PCET).

Mitochondria exploit PCET to build the proton gradient that powers the nanomotors to produce ATP in the electron transport chain (ETC). Many enzymes, such as dehydrogenases and lipoxygenases, exploit proton tunneling to carry out their reactions. Deuterons are much less capable of tunneling, so this becomes a way to select for substrates containing protons rather than deuterons. The very large kinetic isotope effect (KIE) for soybean lipoxygenase is an example of this phenomenon.

NADH-ubiquinone oxidoreductase (Complex I) couples the transfer of two electrons between NADH and ubiquinone to the translocation of four protons across the membrane. This process provides the driving force for ATP synthase, which harnesses the gradient to produce ATP, but it also assures that few, or no, deuterons arrive on the other (intermembrane) side of the membrane, protecting the ATPase nanomotors.

SAMe, the universal methyl donor, plays a crucial role in regulating oxidative phosphorylation (OXPHOS). It is primarily synthesized in the cytoplasm and imported into the mitochondria via the import protein SAMC. SAMC is the only mitoSAM carrier and is required for OXPHOS and oxidative tricarboxylic acid (TCA) metabolism, showing a strong dependency of mitochondrial health on one-carbon (1C) metabolism. We hypothesize that the importance of SAMe to mitochondrial health is directly linked to the plausible theory that SAMe’s methyl groups are normally highly deupleted.

3. Are microbially synthesized methyl groups and butyrate deuterium depleted? – A careful tracing of multiple metabolic processes taking place in a human cell reveals that they are plausibly designed to greatly restrict the number of deuterons that are in the mitochondrial water. This strategy helps to minimize exposure of the ATPase nanomotors to deuterons. In part, this feat is accomplished through enzymes such as flavoproteins that greatly favor protium over deuterium in their reaction, i.e., that have a high deuterium KIE. The physics usually involves configuring the enzyme to support proton tunneling, since deuterons are much less capable of such tunneling.

Another way to support a reduced deuterium supply to the ATPase nanomotors is to select nutrients that are naturally low in deuterium to feed into the tricarboxylic acid (TCA) cycle. This is what makes the metabolites produced by the gut microbes via hydrogen recycling very significant. The enzyme expressed by anaerobic archaea that metabolize TMA, TMADH, is a flavoprotein with a high deuterium KIE (~ 8.6) due to vibrationally assisted hydrogen tunneling.

This means that the hydrogen recycling that takes place during its metabolism further scrubs deuterium from methylation pathways, while TMA that is left behind becomes enriched in deuterium. This unmetabolized TMA is converted to deuterium-enriched trimethylamine N-oxide (TMAO) in the liver and released into the circulation. Elevated TMAO levels in plasma are associated with increased risk to cardiovascular disease and a long list of other inflammatory diseases, as we will detail in the coming sections.

4. Natural and synthetic choline have different effects on TMAO levels: does deuterium play a role? – The original 2011 paper that first identified TMAO as a risk factor for heart disease, involved feeding mice phosphatidylcholine where all the protons in the methyl groups attached to the nitrogen atom were replaced with deuterium, so that the researchers could trace the products of the nutrient in the body. It turns out that they accidentally conducted an experiment testing what happens when phosphatidylcholine is extremely enriched in deuterium. 🙂 They also determined that supplementation of mice with deuterated choline, TMAO, or betaine resulted in upregulation of multiple macrophage scavenger receptors linked to atherosclerosis. TMAO was not produced if the mice were pretreated with antibiotics or in experiments with germ-free mice, confirming that microbial enzymatic action was a necessary precondition.

A paper in 2021 on human subjects compared choline intake from natural dietary sources with supplemental choline bitartrate and found that the latter but not the former raised blood TMAO levels. Notably, these authors wrote in the conclusion of the abstract: ‘Despite high choline content in egg yolks, healthy participants consuming four eggs daily showed no significant increase in TMAO or platelet reactivity.’ However, TMAO levels rose significantly following synthetic choline bitartrate supplementation. This occurred even though the subjects had normal kidney function, showing that elevated TMAO is not just a consequence of kidney disease.

The authors of the original 2011 study had published a follow-on study on human subjects in 2013, in which they supplemented the subjects with D9-PC, essentially repeating the mouse study but with humans as the subjects. They confirmed that D9-TMAO levels were sharply elevated in the plasma and urine following supplementation. Furthermore, an elevated TMAO level predicted an increased risk of major cardiovascular events, after adjustment for traditional risk factors. This study shows that it may not be phosphatidylcholine vs. choline bitartrate that matters, but rather whether the choline is deuterium depleted or deuterium enriched. By contrast, a survey involving over 14,000 participants found that dietary choline protects from both heart disease and stroke. L-carnitine is also a precursor to TMAO, and a mouse study in which the mice were fed deuterated L-carnitine also showed a sharp increase in plasma TMAO following supplementation, further supporting the idea that deuteration is the primary factor promoting TMAO accumulation.

5. TMAO directs metabolism towards deupleting peroxisomal-mitochondrial crosstalk – The synthesis of TMAO from TMA requires hydrogen peroxide. The source of hydrogen peroxide is via peroxisomal fatty acid chain modifications that utilize molecular oxygen dissolved in plasma to produce SCFAs, ketones, NADH and hydrogen peroxide (H₂O₂). The resulting metabolic water of the reaction is deupleted, as fatty acids are inherently deupleted molecules in biology. Although peroxisomes do not produce ATP directly, they reduce NAD⁺ for proton delivery to mitochondria via membrane-based intracellular proton transporters. Although the partial contribution of TMAO synthesis to intermediary metabolism is yet to be determined to efficiently deplete deuterium, it is certain that none of the above works well in the deuterium preserving glucogenic metabolic state. There is a strict dependence of peroxisomes on long chain saturated fatty acid substrates with particularly lower deuterium-related chemical mass.

Peroxisomal metabolism triggered by TMAO turnover utilizes very long and branched chain fatty acids (A) as well as dissolved molecular oxygen (B) carried in plasma. Peroxisomes produce SCFAs via β-carbon oxidation, ketones, NADH (C) and hydrogen peroxide (B). H₂O₂ is rapidly converted to metabolic water by catalase (CAT) that also yields molecular oxygen for the mitochondrial matrix (D) as well as for other cellular compartments. Peroxisomes can also reduce NAD⁺ for proton delivery to mitochondria via membrane-based intracellular proton transporters. oxidation of very long chain saturated fatty acid β carbons, purportedly of animal source, with the help of molecular oxygen, yields the most deupleted H₂O₂ by weight. CAT, one of the fastest enzymes in biology with that of isomerases, rapidly and irreversibly produces water from H₂O₂, while recycling oxygen. Metabolic hydrogen peroxide of fatty acid breakdown with low deuterium consequently provides ATP synthase nanomotor-sparing protons for energy production. High TMAO with hydrogen peroxide turnover can easily depend on CAT-mediated oxygen recycling.

6. Is TMAO an indicator of deuterium overload in the mitochondria?
6.1 TMAO inhibits S-adenosylhomocysteine hydrolase
6.2 TMAO induces reactive oxygen species
6.3 TMAO suppresses autophagy via PI3K/Akt/mTOR activation
7. TMAO and human diseases
8. Does oxidative stress lead to mitochondrial deupletion? – While oxidative stress is a major contributor to cellular damage, the processes involved in resolving ROS are an essential part of the mechanism by which the cell reduces deuterium levels in the mitochondria. Intracellular ROS are derived mainly from NOX, xanthine oxidase, and the mitochondrial electron-transport chain (mETC). Excess mitochondrial deuterium promotes increased ROS generated by the mETC. Superoxide dismutase (SOD) converts ROS to H₂O₂ , which can release the highly destructive hydroxyl radical in the presence of reduced iron (Fe2+). However, H₂O₂ is an excellent source of deuterium depleted water (DDW) in the mitochondria, as long as there is sufficient mitochondrial glutathione and both glutathione peroxidase and glutathione reductase are adequately expressed. H₂O₂ freely crosses the mitochondrial membrane, and, with adequate antioxidant support, it is rapidly converted to two molecules of DDW, catalyzed by glutathione peroxidase.

9. Do lipid-laden foam cells support mitochondrial deupletion?
10. Archaeobiotics
11. A crucial role for A. muciniphila
12. Strategies to lower TMAO levels – It is clear that elevated plasma TMAO is a risk factor for a broad range of chronic diseases, and therefore it is compelling that a strategy that reduces plasma TMAO should show health benefits. However, simply avoiding foods that provide precursors to TMAO is not likely to be productive. Choline, L-carnitine, and betaine are the primary sources that fuel the methylation pathway. Eggs and seafood, rich sources of these nutrients, also contain many valuable micronutrients and healthy fats that are also essential.

Deuterium depleted water (DDW) is commercially available, at dilution levels as low as 5 ppm. It can be mixed with tap water to simulate natural glacier water, typically containing around 100 ppm deuterium. Although the number of studies on the effects of therapeutic deuterium depletion on various health conditions is small, a review paper found that deuterium depletion has shown promise in preventing and treating cancer, improving long-term memory, enhancing sports performance, and reducing symptoms of depression.

It is apparent that the best way to reduce TMAO levels, while simultaneously boosting methylation supplies, is to promote an abundant colonization of anaerobic archaea in the gut, so that they can clear (fully metabolize) TMA before it has a chance to become TMAO.

13. Discussion – In this paper, we develop the argument that TMAO serves as a marker for excess deuterium in the methylation pathway, and, by extension, in the mitochondria, systemically. While methyl groups have powerful epigenetic effects, the ultimate fate of methyl groups is their metabolism to CO₂ and water that is most likely deuterium depleted in the mitochondria. A microbial imbalance leading to reduced colonization by beneficial bacteria and an overgrowth of pathogenic species is the primary cause of overproduction of TMAO.

14. Conclusions – We have shown that TMAO, a causal factor for many diseases, may act as a marker for gut dysbiosis and for excess deuterium load in mitochondria, systemically. We traced through many of the biological pathways involving 1C metabolism and showed the integral role that gut bacteria play in stripping deuterium from methyl groups.”

https://link.springer.com/article/10.1007/s11306-026-02443-3 “The essential role of hydrogen gas recycling by gut microbes in reducing deuterium load in host mitochondria: is trimethylamine oxide a deuterium sensor?”

I take Now brand taurine, acetyl-L-carnitine, flush-free niacin, and betaine. I asked them whether these products are evaluated for their deuterium content. Will update with their response.

Self-reinforcing feedback loops of aging

April 20, 2026April 30, 2026 gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Memory, Stress, Telomeres Control group, DNA methylation, Genetic factors, Neurodegenerative disease, Reciprocity

A 2026 rodent study investigated age-associated queuine decline. Queuine is characterized as a “longevity vitamin” in the cited 2018 review Prolonging healthy aging: Longevity vitamins and proteins, along with ergothioneine, astaxanthin, and taurine.

“The contribution of transfer RNA (tRNA)-specific modifications to aging remains largely unexplored. We systematically profile tRNA modifications across multiple organs, species, and senescence models, and identify mannosyl-queuosine (manQ) as the first tRNA-specific modification that consistently declines with age.

Across species, queuine supplementation extends lifespan and enhances healthspan. In naturally aging mice, long-term oral administration beginning at 16-months-old (human equivalent 50 years) extends mean lifespan by 15.3%, reduces DNA methylation age, improves cognitive and motor performance, strengthens antioxidant defenses, remodels the gut microbiota, and alleviates inflammation and metabolic dysfunction without detectable toxicity.

These findings establish tRNA epitranscriptomic remodeling as a previously unrecognized layer of aging regulation, and identify restoration of manQ through queuine supplementation as a multi-system strategy to delay aging.

manQ hypomodification is selective rather than reflecting global tRNA depletion. Aging preferentially reduces the manQ-containing tRNA^Asp fragment while leaving the corresponding unmodified tRNA^Asp fragment, and other queuosine-modified tRNAs, relatively unchanged.

This pattern supports a regulated defect in modification homeostasis rather than a generalized change in transcript abundance. Such specificity argues that manQ loss is not merely a passive consequence of tissue degeneration, but instead represents a conserved, biologically meaningful aging-associated event with mechanistic impact.

Because proteostasis intersects with multiple canonical hallmarks (e.g. mitochondrial dysfunction, impaired stress resilience, and altered intercellular communication), translation-coupled proteome destabilization offers a unifying explanation for how a single tRNA modification defect can elicit multi-system consequences. In this view, manQ decline is not merely one of many molecular changes observed in aging, but rather a proximate determinant capable of amplifying downstream hallmarks through a common axis of proteome quality control.

Our findings further suggest that manQ depletion may engage self-reinforcing feedback loops that accelerate aging trajectories. This architecture offers a conceptual framework in which aging progressively erodes ‘epitranscriptomic integrity’ at the tRNA level, pushing translation toward an error-prone regime that accelerates proteostatic collapse and functional decline.

A distinctive implication of this work is that queuine introduces a microbiota-host epitranscriptomic axis into aging biology. Queuine is produced by gut microbiota and cannot be synthesized de novo by mammals. These findings expand the conceptual scope of geroscience by placing a microbiota-derived nutrient upstream of translational quality control.

Queuine supplementation offers a distinct therapeutic logic: rather than modulating a single signaling cascade, it restores a tRNA modification state that governs translational fidelity – an upstream determinant of proteome quality that can, in principle, influence multiple downstream hallmarks concurrently. These findings highlight an intervention paradigm centered on restoring molecular fidelity, rather than suppressing a single downstream phenotype, as a strategy to delay systemic aging.”

https://www.biorxiv.org/content/10.64898/2026.03.22.713446v1.full “Evolutionarily Conserved Decline of tRNA Mannosyl-Queuosine Links Translational Regulation to Aging and Is Reversed by Queuine”

Treat your gut microbiota well. Give them what they want, and expect reciprocity.

2026 diet and supplement changes

March 24, 2026 gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system, Stress Control group, DNA methylation, Neurodegenerative disease

I switch things around pretty often, but I haven’t said much about diet and supplement changes since this time last year. Here’s what I’ve done in terms of changes that I’ve since abandoned or reduced, followed by additions or increases that I’ve kept.

Abandoned and reduced items

1. I stopped using Avena sativa oats to grow 3-day-old oats sprouts. I again ran into the same situation where I got < 10% yield.

The first time this happened in 2023, I related to the Montana farmer that degraded seed vitality was probably caused by the way that Amazon handled their oat products. I’m the customer, though, and I won’t make it my problem if the vendor can’t meet expectations.

I switched to sprouting Avena nuda oats based on Sprouting hulless oats. I’ll note that this Illinois farmer doesn’t let Amazon handle their organic Avena nuda oats, and they add on post office shipping costs. They don’t recommend sprouting, probably because of liability, although I’ve had a 91% germination rate over three days. I might have ordered Avena sativa oats directly from the Montana farmer bypassing Amazon if they were also organic.

2. I stopped taking alpha ketoglutarate. In my view, increasing tricarboxylic acid (TCA) cycle intermediate metabolites such as alpha ketoglutarate and CoQ₁₀ should not be the primary way to improve mitochondrial electron transport chain function.

Instead of biochemical considerations, focus on photon modulation, which precedes biochemical reactions. Which means mitochondrial studies should be controlled for light exposures, and very few of them do that, although it’s the way nature works.

This past winter I increased indoor non-LED light exposure within a circadian rhythm framework. I’ll switch back to walking the beach at sunrise from being out in mid-day sun after it gets a little bit warmer.

3. I’ve taken creatine on and off during the past year. There’s a bit of literature on its use for improving methyltransferase system components like homocysteine.

Stopping creatine fits one of the overall patterns that studies demonstrate – people who are initially deficient in the studied item get a benefit, while people who are initially sufficient don’t benefit from treatment. I’ve always tested mid-range for homocysteine, which is desirable.

4. I had some cocoa powder lying around for a year or two, and I used it this past winter to improve the taste of coffee I bought on sale. Cocoa flavanols are supposed to improve various health measures. But I haven’t been provided access to the most recent human studies, so I won’t repeat their results without reading their details.

5. I saw this at Costco, and picked up a package:

A 2025 review covered pecan research, Pecans and Human Health: Distinctive Benefits of an American Nut. Eating pecans seems to have some health benefits, and they taste alright.

For me, though, the dryness of a chewed pecan bolus creates a swallowing problem that walnuts don’t have. YMMV.

6. I stopped taking 2 g magnesium L-threonate. I’ve always tested high for magnesium without using a specific supplement.

7. I reduced D₃ by 25 mcg to a daily 2400 IU. Winter is over.

New and increased items

1. I curated five 2025 ergothioneine studies in Human studies of ergothioneine after stopping mushroom intake via AGE-less chicken soup. I wasn’t thrilled that none of them investigated long-term effects of persistent plasma ergothioneine levels.

This year I decided to start taking the higher 25 mg dose of the first study once a week. That should produce some benefits at a lower ergothioneine blood level than daily doses produce. I’ll check periodically for 2026 research.

2. The only paper I’ve curated on deuterium (heavy hydrogen) is Taurine and mitochondrial health. I started using Icelandic glacier water to make coffee and tea, and for just drinking.

It isn’t advertised as deuterium-depleted water, and it isn’t manufactured as such. But I think any glacier water contains less deuterium than local water. I use local filtered water for sprouting and cooking.

3. Per The return of the free radical theory of aging I started taking extra vitamin C separately from other supplements in the form of Now brand liposomal 1 gram twice daily this past winter. That study found vitamin C to be an anti-aging compound for primates.

Reference 72 of that 2026 paper is a freely available 2025 study https://www.cell.com/cell-stem-cell/fulltext/S1934-5909(25)00339-X “Vitamin C conveys geroprotection on primate ovaries” that used the same vitamin C dose and duration in macaques to find:

“VC slowed aging in various ovarian cell types. Moreover, VC protected human ovarian endothelial and stromal cells (SCs) from aging partially via NRF2 activation. This study establishes a proof-of-concept for delaying primate ovarian aging with a single compound, and provides important insights into preventing and treating degenerative diseases related to ovarian aging.”

4. I restarted taking inulin last year, about 3 grams (a heaping teaspoon) daily after posting Inulin vs. FOS. My 2.5 year-old grandchild takes a level teaspoon daily, as inulin’s beneficial effects aren’t just for old people.

5. I started taking 12 mg astaxanthin twice in the morning. I use Nrf2 activators in the morning because Nrf2 is especially involved in the circadian cycle, as noted in papers such as Broccoli sprouts activate the AMPK pathway, Part 4.

6. I increased daily raw egg consumption from 3 eggs a day to 3 eggs twice daily.

7. This year, Ovega 3 algae oil DHA 420 mg/EPA 140 mg became no longer available AFAIK. I substituted Vegan Omega 3 algae oil DHA 300 mg/EPA 150 mg in the morning and Sports Research Omega 3 fish oil DHA 310 mg/EPA 690 mg in the afternoon.

8. I picked up this Korean seaweed in a 10-pack at Costco. The label doesn’t say what its iodine content is. I eat it as a snack whenever I get a salt craving, maybe once a week.

The return of the free radical theory of aging

March 23, 2026April 13, 2026 gettingwell4 5+ stars Premium, Cerebrum, Epigenetics, Hippocampus, Immune system, Limbic system, Stress Brain neurons, Control group, DNA methylation, Genetic factors, Prefrontal cortex

A 2026 primate study investigated effects of vitamin C:

“Here, we define a conserved iron-lipid axis driving primate aging, termed ‘ferro-aging.’ Multi-tissue profiling in humans and non-human primates reveals age-progressive iron accumulation, fueling chronic lipid peroxidation orchestrated by acyl-coenzyme A (CoA) synthetase long-chain family member 4 (ACSL 4). Distinct from acute ferroptosis, this ACSL4-mediated process promotes cellular senescence and systemic functional decline.

We identify vitamin C (VC) as a direct inhibitor of ACSL4. Long-term VC administration in aged monkeys for over 40 months potently reduces ferro-aging signatures across tissues, attenuates multi-organ pathology, and improves neurological and metabolic functions. Multi-omic aging clocks indicate the VC-mediated reversal of biological age.

Despite decades of interest in oxidative stress, largely sparked by the free radical theory of aging, efforts to modulate it broadly with antioxidants have yielded inconsistent or neutral outcomes, highlighting the theory’s limitations and underscoring the need to identify more specific, upstream drivers. A critical challenge remains: determining whether the iron-lipid axis constitutes a core upstream driver of aging in primates and, if so, whether it is therapeutically targetable.

In this study, we bridge these gaps. We define an iron-triggered, ACSL4-governed, lipid peroxidation-driven program that escalates with age across diverse cell types and multiple organs in non-human primates.

VC treatment dose-dependently increased Nrf2 phosphorylation and activation. VC orchestrates a dual-defense strategy against ferro-aging: it directly suppresses the pro-aging lipid peroxidation driver ACSL4, while in parallel, it bolsters the cell’s intrinsic antioxidant capacity via Nrf2 pathway activation.

Middle-aged cynomolgus monkeys (12–16 years old, approximating human 40–50 years) received daily oral VC (30 mg/kg group) or a control treatment for 40 months under standardized conditions.

Structural MRI analysis demonstrated that VC intervention counteracted age-related brain atrophy. Using general linear mixed models, we found that VC restored cortical surface area in the frontal lobes of aged monkeys. Regional analysis identified enlargement in four regions of the orbital frontal cortex, an area critical for adaptive behavior.

Diffusion MRI-based connectomics revealed that, compared with young animals, aged monkeys exhibited reduced structural connectivity in 18 brain regions. VC treatment restored connectivity in 9 of these regions, which were predominantly located in the posterior parietal cortex, a hub for spatial awareness and decision-making.

VC exerted robust neuroprotective effects. It attenuated heterochromatin loss (increased H3K9me3) in the prefrontal cortex and hippocampus and reduced abnormal protein aggregates, including cytosolic aggresomes and Aβ. Additionally, VC lowered the abundance of activated microglia and astrocytes and suppressed expression of the innate immune sensor cGAS in the hippocampus.

VC supplementation reduced the estimated biological age across multiple organs. At the epigenetic level, VC lowered DNA methylation age in several tissues, including brain, brown adipose tissue, muscle, skin, aorta, and kidney. In the hippocampus, the most substantial reductions in biological age occurred in microglia, oligodendroglia, and oligodendrocyte precursor cells. In the pancreas, alpha cells, beta cells, and ductal cells showed the greatest rejuvenation.

In summary, chronic VC supplementation inhibits the ferro-aging pathway, reduces multidimensional biological age across primate organs, and ameliorates a spectrum of functional declines in nervous and metabolic systems. Our work establishes ACSL4 inhibition as a promising and translationally relevant therapeutic strategy for mitigating aging-related decline.

A long-term, 40-month intervention study in aged non-human primates is a highly translational model given their shared inability with humans to synthesize VC endogenously. The finding that a single, safe nutrient can reverse multidimensional aging clocks in a primate has profound implications for translational longevity medicine.”

https://www.sciencedirect.com/science/article/abs/pii/S1550413126000537 “Vitamin C inhibits ACSL4 to alleviate ferro-aging in primates” (not freely available) Thanks to Dr. Pradeep Reddy for providing a copy.

Grok’s take on this study:

“For humans (who, like macaques, cannot synthesize vitamin C), the Recommended Dietary Allowance (RDA) is 75–90 mg/day for adults (~1–1.5 mg/kg for a 60–70 kg person) to prevent deficiency. Upper safe intake levels are much higher: up to 2,000 mg/day (Tolerable Upper Intake Level) is considered safe for most adults, with no established adverse effects at that level from food/supplements.

Treated monkeys represent advanced aging stages (likely equivalent to human 50s–70s+ based on ‘aged’ designation and long-term intervention effects), extending the prior 12–16-year monkey range (human ~35–55) to broader anti-aging applications. While human trials are needed, the primate evidence (long-duration, systemic benefits) strengthens the case for high-dose, sustained vitamin C as a strategy against ferro-aging in humans. It elevates vitamin C from a nutrient to a targeted anti-aging compound in primates.”

Coincidentally, I started taking extra vitamin C separately from other supplements in the form of liposomal 1 gram twice daily this past winter. Can’t say that it had any effects on my intended target, avoiding sniffles and sneezing, as allergy season kicked off in early February. With this study’s findings, I’ll continue.

Eat broccoli sprouts for your heart, Part 2

December 24, 2025 gettingwell4 4-5 stars Advanced knowledge, Epigenetics Control group, DNA methylation, Genetic factors

A 2025 rodent study investigated synergistic effects of sulforaphane (SFN) and nicotinamide mononucleotide (NMN) on diabetic cardiomyopathy:

“Diabetic cardiomyopathy (DCM) as a significant diabetes complication remains a major human challenge. In this study, we provide evidence that the fat mass and obesity-associated protein (FTO) plays a pivotal role in DCM pathogenesis.

Downregulation of FTO in DCM acts as a critical inducer of ferroptosis by increasing expression of acyl-CoA synthetase long-chain family 4 (ACSL4), a key positive mediator of ferroptosis. FTO-mediated mitigation of ferroptosis occurs in an ACSL4-dependent manner which leads to increased methylation of Acsl4 transcripts.

Ferroptosis plays an essential role in the pathogenesis of DCM.

As the most widespread mRNA modification, N⁶-methyladenosine (m6A) is globally downregulated and implicated in diabetes and its complications.

FTO, which is an m6A demethylase, was found to be downregulated in diabetes and its cardiovascular complications.

NAD⁺ enhances the demethylase activity of FTO. Dietary supplementation with NMN, a critical intermediate in the NAD⁺ biosynthetic pathway, has been shown to efficiently elevate endogenous NAD⁺ levels.

Enhancing the demethylase activity of FTO with NMN combined with SFN targeting NRF2 could synergistically reduce the level of lipid peroxides to inhibit ferroptosis, providing an effective avenue for alleviating DCM.

We found that NMN could alleviate ferroptosis and improve heart function through enhancing FTO. SFN could prevent ferroptosis and partly rescue heart function via AMPK-mediated NRF2 activation.

We demonstrated that SFN combined with NMN treatment could significantly inhibit lipid peroxidation and rescue cardiac function in DCM compared to SFN or NMN treatment alone.

Although the combined regimen further suppressed ferroptosis and improved cardiac performance, it fell short of complete remission, underscoring that additional pathways also contribute substantially to the pathogenesis of DCM.”

https://link.springer.com/article/10.1007/s12012-025-10080-w “FTO-Mediated Mitigation of Ferroptosis Occurs in an ACSL4-Dependent Manner in Diabetic Cardiomyopathy”

The epigenetic mechanism involved with this study’s dietary dissolved-in-water 100mM NMN dose was Non-CpG methylation. This study used the same very low sulforaphane dose intraperitoneally injected as Eat broccoli sprouts for your heart. Discussion of that study provided an example that if a person waited until a diabetes-related disease condition became a problem, capabilities to adequately address causes and prevent the problem may be lost.

Notice in the last bar of the second graphic above taken from Figure 7 that the combined treatment was also provided to non-diabetic mice. These researchers provided over a dozen other measurements in Figure 7 to show similar short-term non-effects of the combined treatment, i.e. that it neither benefited nor harmed non-diabetic subjects. Grok interpreted this study’s 3-month-long intervention to be a 1-to-5 year human equivalent, depending on the measured effect (shorter for metabolic effects like MDA, longer for structural cardiac changes like reduced ferroptosis.)

The male subjects began at 2-months old, a human-equivalent 15-20 years old. These researchers gave them diabetes by feeding them a “high-fat diet for 3 months to induce insulin resistance, followed by a single intraperitoneal injection of streptozotocin (STZ) (in 0.1 mol/L of citrate acid buffer, 60 mg/kg) to induce partial insulin deficiency.” A 5-months old mouse is a 25-30 years old human equivalent.

Grok considered this study’s NMN human equivalent dose to be extremely high if provided in drinking water, but not if injected, depending on volume. However, the study didn’t state that its NMN dose was injected, and there was no dose volume indicated.

Human studies of astaxanthin – Part 1

December 7, 2025December 8, 2025 gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Immune system, Stress Control group, DNA methylation, Genetic factors

Here are three 2025 clinical trials of the Nrf2 activator astaxanthin’s effects. Let’s start with a clinical trial of inflammation-related diabetic complications and insulin resistance:

“We investigated effects of 10 mg/day astaxanthin (ASX) supplementation for 12 weeks on microRNAs (miRNAs), lysophosphatidylcholine (LPC), and α-hydroxybutyrate (α-HB) as novel factors in development of a variety of diabetes-related complications.

LPC is believed to play a significant role in atherosclerosis and inflammatory diseases by modifying functions of multiple cell types, including smooth muscle cells, endothelial cells, monocytes, macrophages, and T cells. LPC can interfere with glucose-stimulated insulin secretion by impairing calcium homeostasis and other signaling pathways that are crucial for the proper functioning of beta cells. This impairment exacerbates hyperglycemia in diabetic patients. LPCs may impede insulin signaling pathways, thereby contributing to insulin resistance (IR).

α-HB is also an indicator of IR and impaired glucose regulation, both of which appear to result from excessive lipid oxidation and oxidative stress. The European population cohorts in 2016 identified α-HB as a selective biomarker for decreased glucose tolerance and prediabetes, which was independent of age, sex, BMI, and fasting glucose.

A number of studies have established a link between miR-21, miR-34a, and miR-155 and diabetic complications such as retinopathy and nephropathy.

In the ASX group, participants were divided into 2 subgroups according to the urinary albumin-to-creatinine ratio (ACR) (< 30 mg/g or ≥ 30 mg/g, an indicator of diabetic kidney disease).

The level of fasting plasma glucose before and after 12 weeks of treatment with ASX was 139.27 ± 21.18 vs. 126.43 ± 18.97 (p = 0.002), demonstrating a significant reduction compared to the placebo group.

In the ASX group, the mean HbA1c level at baseline was 7.89 ± 0.79 and declined to 7.05 ± 0.35 after the supplementation period, which was statistically significant.

Supplementation with ASX resulted in a statistically significant drop in HOMA-IR levels, whereas this parameter was not altered significantly in the placebo group.

The ASX group, in comparison with the placebo group, demonstrated marked changes in lipid profile factors such as TC, TG, and LDL (p = 0.011, p = 0.043, and p = 0.022, respectively).

Clinical studies indicate that rigorous diabetes management does not substantially diminish appearance of complications. Modifications in oxidative stress and IR markers, as well as miRNA expression, must be analyzed to identify biological markers with sufficient predictive power for development of complications in diabetic patients.

Supplementation with ASX substantially diminished the levels of α-HB, LPC, and inflammation-related miRNAs in diabetic patients with and without complications.”

https://onlinelibrary.wiley.com/doi/10.1155/ije/5878361 “Astaxanthin Modulates Inflammation in Type 2 Diabetes via Regulation of microRNAs, Lysophosphatidylcholine, and α-Hydroxybutyrate”

Another clinical trial investigated astaxanthin’s effects in heart failure patients:

“Chronic heart failure (HF) is often linked to increased oxidative stress and metabolic issues like high uric acid, which can worsen outcomes.This study aimed to investigate the effects of ASX supplementation on oxidative stress markers as the primary outcome and clinical symptoms in patients with HF.

80 patients with HF were enrolled and randomly assigned to receive either ASX (20 mg/day) or a placebo (20 mg/day of maltodextrin) for 8 weeks. Biomarkers including total antioxidant capacity (TAC), malondialdehyde (MDA), superoxide dismutase (SOD), serum uric acid (UA), and clinical symptoms (dyspnea, fatigue, appetite) were assessed pre-and post-intervention.

Daily supplementation with 20 mg of ASX for eight weeks in patients with HF resulted in significantly greater improvements in oxidative stress biomarkers compared to placebo group. This improvement included reductions in uric acid and MDA, along increases in TAC and SOD.

In our study, participants received the cis-isomer form of ASX. The cis-isomer of ASX demonstrates greater anti-inflammatory and antioxidant properties than the trans-isomer, along with enhanced bioavailability. Inconsistencies among studies may be attributed to differences in participants’ baseline antioxidant status, underlying medical conditions, dosage, isomeric form and formulation of ASX used, and the duration of intervention.

One of the strengths of this study is that it represents the first randomized clinical trial to evaluate the effects of ASX supplementation on oxidative stress markers, UA levels, and clinical symptoms in patients with HF. Additionally, potential confounding factors were controlled as much as possible. However, several limitations were identified, including the relatively short intervention duration, limited sample size, limited generalizability of the findings due to the single-center design, absence of blood ASX level measurements, and lack of long-term follow-up.”

https://link.springer.com/article/10.1186/s12872-025-05260-z “Impact of astaxanthin on oxidative markers, uric acid, and clinical symptoms in heart failure: a randomized clinical trial”

A third clinical trial evaluated astaxanthin’s effects as an adjunct to standard treatment of community-acquired pneumonia:

“Adult patients diagnosed with community-acquired pneumonia (CAP) were enrolled and assigned to receive either 12 mg/day ASX or a placebo in addition to standard antibiotic therapy for 7 days. Inflammatory markers, including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and interleukin-10 (IL-10), were measured at baseline and post-treatment. Secondary outcomes included Sequential Organ Failure Assessment (SOFA) and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores.

A total of 80 patients (40 per group) completed the study. Patients receiving ASX exhibited significant reductions in pro-inflammatory cytokines compared to the placebo group. IL-6 and TNF-α levels were significantly lower in the ASX group at the end of the study (P < 0.05). Additionally, SOFA and APACHE II scores showed greater improvements in ASX-treated patients, suggesting a potential role in mitigating disease severity.

These findings suggest that ASX may help preserve organ function, limit the progression of inflammatory injury, and reduce overall disease severity in hospitalized patients with CAP.

ASX is widely regarded as the most potent carotenoid, owing to its unique molecular structure. Its polar-nonpolar-polar configuration enables it to span lipid bilayers and neutralize ROS both within and outside cellular membranes—an advantage not shared by other carotenoids that tend to localize at the membrane surface.

Despite the positive findings of this study, some limitations should nevertheless be considered.

The relatively small sample size may have limited the statistical power to detect differences in some outcomes and affects the generalizability of the findings.

Microbiological data on CAP pathogens were not collected. As different microorganisms can trigger distinct inflammatory responses, this limits our ability to assess pathogen-specific variations in ASX efficacy.

A notable limitation of this study is the short follow-up duration, with outcomes assessed only over a 7-day period. While this timeframe offers insight into the acute effects of ASX on inflammatory and OS markers, it does not clarify whether these benefits are sustained beyond the immediate treatment window.

The fixed dose of 12 mg once daily may not have maintained optimal therapeutic levels throughout the day. Dose-ranging studies and evaluations of alternative regimens are needed to determine the most effective strategy.”

https://www.frontiersin.org/journals/pharmacology/articles/10.3389/fphar.2025.1621308/full “The anti-inflammatory and antioxidant effects of astaxanthin as an adjunctive therapy in community-acquired pneumonia: a randomized controlled trial”

Part 2 continues with four more 2025 human studies of astaxanthin.

Ancient DNA fragments enable adult neurogenesis

October 20, 2025October 20, 2025 gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Hippocampus, Limbic system, Memory Brain neurons, Control group, DNA methylation, Genetic factors, Neural plasticity

A 2025 rodent study investigated mechanisms by which erythropoietin (EPO) enables adult neurogenesis and cognitive function:

“We mapped epigenomic and transcriptional landscapes of adult mouse hippocampus under recombinant human EPO (rhEPO) treatment. We discovered significant lineage-specific remodelling of chromatin accessibility predominantly in newly formed pyramidal neurons, highlighting a robust EPO-driven neurogenic response. Notably, transposable elements (TEs), particularly ancient LINEs and SINEs, emerged as critical cis-regulatory elements (cCREs).

EPO is known to be upregulated in the brain under hypoxic or injury conditions, and it has been considered a natural neuroprotective agent. We demonstrated that EPO, a traditionally hematopoietic hormone, can profoundly reprogram the adult neural epigenome to drive neurogenesis.

EPO may activate a specific subclass of dormant regulatory elements to drive nearby genes. Such a mechanism would represent a previously unappreciated mode of gene regulation: the de novo recruitment of ancient genomic elements to drive a contemporary cellular response.

Our data support the model that EPO drives differentiation of progenitors rather than inducing widespread cell division. The net effect is an enrichment of pyramidal neurons at the cost of interneurons. Pyramidal neurons integrate in the hippocampal circuitry, leading to potential implications for mood, memory, cognitive enhancement, and recovery from brain injury.

We propose a conserved evolutionary mechanism at play: ancient TEs embedded in the genome have been repurposed as cCREs in neural cells, and during an EPO-induced neurogenic stimulus, the brain taps into this reservoir of regulatory elements to rapidly reshape gene expression. In evolutionary terms, this represents an efficient strategy.”

https://www.biorxiv.org/content/10.1101/2025.10.13.682070v1.full “Transposable Element-Mediated Epigenomic Remodeling Drives Erythropoietin-Induced Neurogenesis in the Adult Hippocampus”

Plasmapheresis doesn’t reduce biological age

July 24, 2025 gettingwell4 4-5 stars Advanced knowledge, Epigenetics Control group, DNA methylation

A 2025 clinical trial investigated effects of plasmapheresis as measured with epigenetic clocks:

“This study aimed to assess whether plasmapheresis without volume replacement with young plasma or albumin affects epigenetic age and other biomarkers in healthy adults. No significant epigenetic rejuvenation was observed based on epigenetic clock measurements. Instead, plasmapheresis was associated with increases in DNAmGrimAge, the Hannum clock, and the Dunedin Pace of Aging.

The relatively small sample size of 34 finishing participants comprising of first-time plasma donors limits the statistical power and generalizability of our findings.

Our cohort was restricted to individuals aged 40 to 60 years in accordance with Czech regulatory guidelines, which, although intentional to focus on an older population where rejuvenating effects might be most apparent, constrains evaluation of age-related differences across a broader demographic.

The 18-week duration of the study, while sufficient to detect rapid alterations in key biomarkers under an intensive plasmapheresis protocol, may not fully capture the long-term implications of these changes.

Due to our trial taking place during spring and summer months, we cannot fully separate the effects of increased sunlight exposure, outdoor physical activity, and dietary changes from the observed rises in Vitamin D and concurrent shifts in DNAm-based aging metrics. We did not collect objective measures of activity or diet, so these factors remain potential confounders.

The protocol of donating plasma every two weeks, although deemed safe by many countries around the world, is not yet well researched and cannot therefore be marked as benefiting to the donor right now. Further refinement to balance clearance of pro-aging factors with maintenance of systemic homeostasis is needed.”

https://www.nature.com/articles/s41598-025-05396-0 “Human clinical trial of plasmapheresis effects on biomarkers of aging (efficacy and safety trial)”

Betaine as an exercise mimetic

July 7, 2025 gettingwell4 5+ stars Premium, Cortisol, Epigenetics, Immune system, Memory, Neurochemicals, Stress Control group, DNA methylation, Genetic factors

A 2025 human study investigated effects of long-term exercise:

“Exercise has well-established health benefits, yet its molecular underpinnings remain incompletely understood. We conducted an integrated multi-omics analysis to compare effects of acute vs. long-term exercise in healthy males.

Acute exercise induced transient responses, whereas repeated exercise triggered adaptive changes, notably reducing cellular senescence and inflammation and enhancing betaine metabolism. Exercise-driven betaine enrichment, partly mediated by renal biosynthesis, exerts geroprotective effects and rescues age-related health decline in mice.

Betaine binds to and inhibits TANK-binding kinase 1 (TBK1), retarding the kinetics of aging.

Betaine effectively alleviated senescence phenotypes by reduced senescence-associated β-galactosidase (SA-β-Gal)-positive cells, decreased p21 expression, lowered DNA damage indicator γ-H2A.X, and elevated heterochromatin mark H3K9me3. Betaine treatment also enhanced cellular antioxidant capacity, as evidenced by increased NRF2 phosphorylation and reduced ROS accumulation.

These findings systematically elucidate the molecular benefits of exercise, and position betaine as an exercise mimetic for healthy aging.”

https://doi.org/10.1016/j.cell.2025.06.001 “Systematic profiling reveals betaine as an exercise mimetic for geroprotection” (not freely available) Thanks to Dr. Weimin Ci for providing a copy.

Nrf2 activators and transcriptomic clocks

May 18, 2025May 18, 2025 gettingwell4 2-3 stars Required further work, Epigenetics, Stress Brain neurons, Control group, DNA methylation, Embryo development, Genetic factors, Neurodegenerative disease

Two preprint studies looked at making transcriptional aging clocks using Nrf2 activators. Let’s start with a 2025 nematode study that used constant exposure to sulforaphane at different concentrations:

“To explore the potential of sulforaphane as a candidate natural compound for promoting longevity more generally, we tested the dose and age-specific effects of sulforaphane on C. elegans longevity, finding that it can extend lifespan by more than 50% at the most efficacious doses, but that treatment must be initiated early in life to be effective. We then created a novel, gene-specific, transcriptional aging clock, which demonstrated that sulforaphane-treated individuals exhibited a “transcriptional age” that was approximately four days younger than age-matched controls, representing a nearly 20% reduction in biological age.

The clearest transcriptional responses were detoxification pathways, which, together with the shape of the dose-response curve, indicates a likely hormetic response to sulforaphane. The hormetic, stress-pathway inducing properties of sulforaphane may indicate that many beneficial dietary supplements work in a fairly generic fashion as mild toxins rather than being driven by the biochemical properties of the compounds themselves (e.g., as antioxidants).

These results support the idea that robust longevity-extending interventions can act via global effects across the organism, as revealed by systems level changes in gene expression.”

https://www.biorxiv.org/content/10.1101/2025.05.11.653363v1 “The broccoli derivative sulforaphane extends lifespan by slowing the transcriptional aging clock”

There are difficulties in researchers translating nematode studies to mammals and humans. Nematodes lack a homolog to the Keap1 protein, which is sulforaphane’s main mammalian target to activate Nrf2.

A 2024 study developed various mammalian epigenetic clocks:

“A unified transcriptomic model of mortality that encompasses both aging and various models of lifespan-shortening and longevity interventions (i.e., mortality clocks) has been lacking. We conducted an RNA-seq analysis of mice subjected to 20 compound treatments in the Interventions Testing Program (ITP).

We sequenced the transcriptomes of a large cohort of ITP mice subjected to various neutral and longevity interventions, expanded the dataset with publicly available gene expression data representing organs of mice and rats across various strains and lifespan-regulating interventions, connected these models with survival data, and performed a meta-analysis of aggregated 4,539 rodent samples, which allowed us to identify multi-tissue transcriptomic signatures of aging, mortality rate, and maximum lifespan.

Aging and mortality were characterized by upregulation of genes involved in inflammation, complement cascade, apoptosis, and p53 pathway, while oxidative phosphorylation, fatty acid metabolism, and mitochondrial translation were negatively associated with mortality, both before and after adjustment for age.

Utilizing the aggregated dataset, we developed rodent multi-tissue transcriptomic clocks of chronological age, lifespan-adjusted age, and mortality. While the chronological clock could distinguish the effect of detrimental genetic and dietary models, it did not show a decrease in biological age in response to longevity interventions. In contrast, clocks of lifespan-adjusted age and mortality both captured aging-associated dynamics and correctly predicted the effect of lifespan-shortening and extending interventions.

Transcriptomic biomarkers developed in this study provide an opportunity to identify interventions promoting or counteracting molecular mechanisms of mortality, and characterize specific targets associated with their effects at the level of cell types, intracellular functional components, and individual genes. Our study underscores the complexity of aging and mortality mechanisms, the interplay between various processes involved, and the clear potential for developing therapies to extend healthspan and lifespan.”

https://www.biorxiv.org/content/10.1101/2024.07.04.601982v1.full “Transcriptomic Hallmarks of Mortality Reveal Universal and Specific Mechanisms of Aging, Chronic Disease, and Rejuvenation”

This second study’s references included an ITP study curated in Astaxanthin and aging, which stated:

“Despite the fact that the average diet contained 1840 ppm astaxanthin (only 46% of the target), median lifespans of male UM-HET3 mice were significantly improved. Amounts of dimethyl fumarate (DMF) in the diet averaged 35% of the target dose, which may explain the absence of lifespan effects.”

So screw-ups in making both astaxanthin and DMF mouse chows ended up with study data that didn’t measure the full lifespan impacts of activating transcription factor Nrf2. I’ll assert that such faulty data may have deviated this second study by downplaying Nrf2 activation’s impact on aging, chronic disease, and rejuvenation.

Sponsors may be less likely to be presented sulforaphane and other Nrf2 activator candidates for future aging and chronic disease studies as this first study suggests, thinking that these have already been studied in mammals. Well, maybe these compounds haven’t been accurately studied. There’s no effective way to fix a rodent study’s missing DMF Nrf2 data and faulty astaxanthin Nrf2 data to train an epigenetic clock in this second study.

I could be wrong about this second study using faulty astaxanthin Nrf2 data. It was cited as Reference 27 in the Introduction as an ITP study, but not specifically cited in the Method section. I don’t know how findings such as one of Nrf2’s target genes (“Remarkably, one of the top genes positively associated with maximum lifespan and negatively associated with chronological age and expected mortality was Gpx1, encoding the selenoprotein glutathione peroxidase 1″) and a Nrf2 specific pathway (Phase II) (“Pathways positively associated with lifespan and negatively with mortality, both before and after adjustment for age, included..xenobiotic metabolism..”) were made without Reference 27. Neither of the above studies has been peer reviewed yet.

The third phase of reversing aging and immunosenescent trends

May 11, 2025May 24, 2025 gettingwell4 5+ stars Premium, Brain development, Epigenetics, Immune system Control group, DNA methylation, Embryo development, Genetic factors, Neurodegenerative disease

Here’s a 2025 interview with Dr. Greg Fahy:

“We found that we could statistically demonstrate thymic regeneration morphologically on single individuals at single time points. MRI changes really are detecting shifts from the fatty tissue infiltration state of the involuted thymus to the regenerated thymus with functional thymic epithelial cells.

When you go through puberty your thymus involutes so you don’t have much left even when you’re 40. Essentially the process consists of loss of functional thymic mass and replacement of that functional thymic mass with adipose tissue, that’s what thymic involution is. It continues throughout life, but you retain a small amount of functional thymic mass all the way out to the age of 107.

The function of the thymus is to essentially manufacture half of your immune system. You have precursor cells arise from the bone marrow. They either go into the meiotic lineage and turn into the innate immune system, or you have the lymphocytic cells for what turns into T cells that enter the thymus and are educated in the thymus to grow up into newborn T cells and they’re released into the bloodstream.

The thymus has two jobs. It manufactures these lovely T cells without which you die but it also has a secondary finishing school. In the thymus cortex you manufacture all these lovely T cells but in the thymus medulla the T cells go to the medulla and if they don’t pass the second examination that they have to pass before they release into the body they’re all killed off. That second examination is: Do you reject self? As we get older, the thymus weakens in both the functions of making the T cells and screening out the ones that attack self. It stands to reason as we get older and the thymus’ influence wanes, we’re going to get more autoimmune disorders.

It took people a while to catch on to the fact that this involution problem is really a significant issue because the T cells that you made when you were 12, and even 20 and 40, they’re probably lasting until you’re 60. But at some point they don’t get replaced as fast as they’re going out of existence, and then your immune system goes off the cliff. Between the ages of 62 and 78 you lose 98% of your ability to recognize foreign antigens, and you still have a lot of capacity left.

We had nine guys in the first trial. Second trial we had 18 men 6 women and 2 controls that happen to be contemporaneous with that group. We have some more controls now that are either finished or or nearing completion. The second population was older than the first population by about nine years, but based on the epigenetic clocks that we looked at, they were starting off biologically younger.

On this last data analysis for Triim XA we looked at 21 different aging clocks. One aspect of the noise that we’re talking about is that biological aging as measured by some of these clocks is circadian. If you measure your age at 4:00 a.m. versus 11:00 a.m. you’re going to get a different result. It’s dynamic and there’s a trend and over time you change in a certain direction, but over any short period of time you can bounce around a little bit. The clocks predict your probability of cognitive dysfunction, they predict your probability of having impairments in your daily life, and they also predict your mortality.

We’re pretty much wrapping up that second clinical trial and going into the third. As we look at more data we understand more and more things and we see more and more things that we previously were not aware of. We began to look at a phenomena that may be responsible for limiting the magnitude of responses that we’re seeing limiting the aging reversal.

Triim-XD which is the next flavor of Triim-X is going to be looking at shifting biochemical pathways in such a way that it optimizes effects of these three medications that we’re giving people [human growth hormone, DHEA, and metformin] and prevents contradictions between them and prevents side effects of each one of these things. That’s about all I can tell you right now.”

Charts regarding the discussed item of how long effects may last are covered in The next phase of reversing aging and immunosenescent trends which was the last time I curated this research effort.

2025 α-ketoglutarate research

March 31, 2025 gettingwell4 4-5 stars Advanced knowledge, Dopamine, Epigenetics, Glutamate, Hippocampus, Immune system, Limbic system, Memory, Neurochemicals, Serotonin, Stress Brain neurons, Control group, DNA methylation, Genetic factors, Neural plasticity

I haven’t mentioned α-ketoglutarate for a while, although I’ve taken it twice a day for several years. Here are four 2025 papers on α-ketoglutarate, starting with a review of its role in bone health:

“α-Ketoglutarate (α-KG) serves as a pivotal intermediate in various metabolic pathways in mammals, significantly contributing to cellular energy metabolism, amino acid metabolism, and other physiological processes. α-KG may be a therapeutic target for a variety of bone-related diseases, such as osteoporosis, osteoarthritis, and rheumatoid arthritis, because of its role in maintaining metabolic balance of bone.

α-KG, as a rate-determining mitochondrial intermediate, is crucial in cell energy metabolism because it connects intracellular carbon and nitrogen metabolism between isocitrate and succinyl coenzyme A. Additionally, α-KG is closely involved in the amino acid cycle. As a precursor of amino acids such as glutamine and glutamic acid, α-KG plays a direct role in energy production and a wide range of cellular chemical reactions. α-KG provides an energy source, stimulating protein synthesis, inhibiting protein degradation in muscle, and serving as a significant metabolic fuel for gastrointestinal cells.

α-KG promotes osteogenic differentiation of stem cells, increases activity of osteoblasts to promote osteogenesis, and inhibits bone resorption activity of osteoclasts. α-KG in articular cartilage promotes differentiation and maturation of chondrocytes and formation of a cartilage matrix. The protective effect of α-KG on bone has practical value in treatment of abnormal bone loss symptoms in various bone tissue diseases.”

https://www.sciengine.com/ABBS/doi/10.3724/abbs.2025020 “Essential role of the metabolite α-ketoglutarate in bone tissue and bone-related diseases”

A rodent study explored adding α-KG to osteoarthritis treatment:

“Mesenchymal stem cell (MSC) therapy represents a promising treatment strategy for osteoarthritis (OA). Nevertheless, the therapeutic efficacy of MSCs may be attenuated under conditions of cellular senescence or when the available clinical quantity is insufficient. α-Ketoglutarate (AKG) exerts beneficial effects on skeletal tissues and activity of stem cells. The present study was designed to explore the potential of AKG in augmenting viability of MSCs and the potential of their combined utilization in treatment of OA.

AKG plays a crucial role in multiple biological processes. It is involved in regulating stem cell differentiation, exerts anti-apoptotic effects, modulates the body’s immune and inflammatory responses, contributes to muscle and bone development, and is essential for maintaining stability of the cartilage matrix.

Platelet-rich plasma (PRP) has been demonstrated to have protective effects on chondrocytes and can effectively repair damaged cartilage in OA. However, PRP has intractable problems in terms of product quality control and allogeneic application, and its long-term therapeutic effect gradually weakens.

Combining AKG’s regulation of cellular metabolism with the multi-directional differentiation and immunomodulatory functions of MSCs is likely to generate a synergistic effect. This combined treatment modality targets the complex pathological processes of OA, including cartilage damage, inflammatory responses, and extracellular matrix imbalance, in a more comprehensive manner than a single therapy.”

https://www.sciencedirect.com/science/article/pii/S2707368825000032 “The repair effect of α-ketoglutarate combined with mesenchymal stem cells on osteoarthritis via the hedgehog protein pathway”

A rodent study investigated whether α-KG has a role in determining frailty:

“Frailty is an age-related geriatric syndrome, for which the mechanisms remain largely unknown. We performed a longitudinal study of aging female (n = 40) and male (n = 47) C57BL/6NIA mice, measured frailty index, and derived metabolomics data from plasma samples.

We find that frailty related metabolites are enriched for amino acid metabolism and metabolism of cofactors and vitamins, include ergothioneine, tryptophan, and alpha-ketoglutarate, and present sex dimorphism. We identify B vitamin metabolism related flavin adenine dinucleotide and pyridoxate as female-specific frailty biomarkers, and lipid metabolism related sphingomyelins, glycerophosphoethanolamine and glycerophosphocholine as male-specific frailty biomarkers.

We were interested to observe whether metabolite abundance at any specific timepoint was associated with frailty at a future timepoint. Unfortunately, we didn’t observe any metabolites that showed an overall significant association with future FI (FI_f) or future devFI (devFI_f). When focusing only on the abundance of metabolites at the baseline time point (∼400 days), we found a single metabolite, alpha-ketoglutarate, was negatively associated with both FI_f and devFI_f.”

https://www.biorxiv.org/content/10.1101/2025.01.22.634160v1.full “Metabolomics biomarkers of frailty: a longitudinal study of aging female and male mice”

Wrapping up with a rodent study adding α-KG to exercise for its effects on depression and learning:

“aKG acts as a prophylactic and antidepressant to effectively counteract social avoidance behaviors by modulating BDNF levels in the hippocampus and nucleus accumbens. Exercise increases aKG levels in the circulation.

In mice, aKG supplementation prolongs lifespan and reduces aging-associated frailty. aKG supplementation also reverses aging in humans as measured by DNA methylation patterns.

aKG functions as a co-factor for epigenetic enzymes. Changes in the intracellular αKG/succinate ratio regulates chromatin modifications, including H3K27me3 and ten-eleven translocation (Tet)-dependent DNA demethylation. The ability of aKG to influence epigenetic status of cells may explain both its prophylactic and anti-depressant effects since transcriptional dysregulation and aberrant epigenetic regulation are unifying themes in psychiatric disorders. This may also explain its ability to differentially regulate BDNF expression in the hippocampus and NAc.

If exercise mediates its effects through aKG, aKG may be a pivotal component of an exercise pill along with lactate and BHB that can serve as both a prophylactic and antidepressant treatment for depression.”

https://www.sciencedirect.com/science/article/pii/S266717432500031X “α-ketoglutarate (aKG) is a circulatory exercise factor that promotes learning and memory recall and has antidepressant properties

Epigenetic clock analysis of a clinical trial

March 7, 2025 gettingwell4 4-5 stars Advanced knowledge, Epigenetics, Memory, Stress Control group, DNA methylation, Genetic factors, Neural plasticity

A 2025 paper performed post-hoc epigenetic clock analyses of a supplement and exercise clinical trial completed earlier this decade:

“We report results of a post hoc analysis among 777 participants of the DO-HEALTH trial on the effect of vitamin D (2,000 IU per day) and/or omega-3 (1 g (330 mg EPA plus 660 mg DHA from marine algae) per day) and/or a home exercise program (a strength-training exercise program performed for 30 min three times per week) on four next-generation DNA methylation (DNAm) measures of biological aging (PhenoAge, GrimAge, GrimAge2 and DunedinPACE) over 3 years. Omega-3 alone slowed the DNAm clocks PhenoAge, GrimAge2 and DunedinPACE, and all three treatments had additive benefits on PhenoAge.

Inclusion criteria were age 70 years and older, living at home, having no major health events (no cancer or myocardial infarction) in the 5 years before enrollment, having sufficient mobility to visit the study centers without help and having good cognitive function with a Mini-Mental State Examination score of at least 24. 777 provided consent for these analyses and had samples available after the application of the exclusion criteria. This group of individuals formed our analysis sample, which had the following characteristics: 59% were women; the mean age at baseline was 75 years; 30% had 25-hydroxyvitamin D (25(OH)D) levels of <20 ng ml−1; 53% were healthy agers as defined in the Nurses’ Health Study (free of major chronic diseases, disabilities, cognitive impairments and mental health limitations); and 88% were physically active (29% were active one to three times per week, and 59% were active more than three times per week). The Swiss participant subgroup represents a healthier and more active subgroup within the total DO-HEALTH population.

Overall, from baseline to year 3, standardized effects ranged from 0.16 to 0.32 units (2.9–3.8 months). In summary, our trial indicates a small protective effect of omega-3 treatment on slowing biological aging over 3 years across several clocks, with an additive protective effect of omega-3, vitamin D, and exercise based on PhenoAge.”

https://www.nature.com/articles/s43587-024-00793-y “Individual and additive effects of vitamin D, omega-3 and exercise on DNA methylation clocks of biological aging in older adults from the DO-HEALTH trial”

These epigenetic clock measurements of a subset of trial subjects was interesting, although I didn’t find it particularly relevant to what I do. I take twice as much Vitamin D and omega-3s everyday, do resistance exercises once or twice a week whenever I’ve recovered from the previous session, walk a few miles on the beach if the weather is nice, and other things.

I don’t bother with epigenetic clock measurements anymore because the free one (PhenoAge) is too variable to be personally accurate. For other clocks, it would be meaningless if all I got was a 2-3 month improvement over a three year period like this trial. Studies usually find that the most deficient subjects at the beginning are the ones that show the greatest improvements with effective treatments. Unhealthiness on any epigenetic clock parameter probably wouldn’t be my starting point, so I may not show even a one-month improvement over three years.

Dr. Goodenowe offered his opinion on the paper:

“DHA is a polyunsaturated fatty acid that is essential for maintaining youthful fluidity of the body’s membranes. While our bodies can make DHA from the essential omega-3 dietary fatty acid, as we get older, our ability to make DHA decreases and oxidative stress on our bodies increases. These two factors contribute to our membranes becoming stiffer and less pliable as we age, in other words, ‘older.’

Because getting older and losing function appear to go hand in hand, we equate aging with a loss of function. As such, we think that aging causes this loss of function, like a disease. Instead, the opposite is true, and it’s the loss of function that causes aging. To slow aging you need to focus on maintaining function.”

https://www.prevention.com/health/a63850396/vitamin-exercise-boost-longeivty-study/ “Scientists Find Taking This Vitamin Boosts Longevity, Add Years to Your Life”

Prevention magazine’s editors need to better proof their writers’ work before it gets published. Unlike the headline, the trial had nothing to do with adding years to human lifespan.

Failed aging paradigms

December 14, 2024 gettingwell4 2-3 stars Required further work, Brain development, Epigenetics, Memory Control group, DNA methylation, Embryo development, Genetic factors, Infants

A 2024 paper with 81 coauthors presented different views of aging:

“This article highlights the lack of consensus among aging researchers on fundamental questions such as the definition, causes, and onset of aging as well as the nature of rejuvenation. Our survey revealed broad disagreement and no majority opinion on these issues.

We obtained 103 responses (∼20% of which were submitted anonymously). The respondents included 29.8% professors, 25% postdoctoral fellows, 22.1% graduate students, 13.5% industry professionals, and 9.6% representing other categories (a total of eight additional groups).

When does aging begin? At 20 years (22%), gastrulation (18%), conception (16.5%), gametogenesis (13%), 25 years (11%), birth (8%), 13 years (5%), and 9 years (4%). Nobody chose the only remaining option (30 years).

It is clear from responses that aging remains an unsolved problem in biology. While most scientists think they understand the nature of aging, apparently their understanding differs. Where some may stress the importance of targeting underlying mechanisms, others focus on ameliorating the phenotypes.”

https://academic.oup.com/pnasnexus/article/3/12/pgae499/7913315?login=false “Disagreement on foundational principles of biological aging”

I’ll assert that these researchers were unable to incorporate information outside of their chosen paradigm. This would explain why only 18% understood the embryonic stage of gastrulation as aging’s start, although the 2022 paper Epigenetic profiling and incidence of disrupted development point to gastrulation as aging ground zero in Xenopus laevis provided epigenetic clock evidence that:

“It is not birth, marriage, or death, but gastrulation which is truly the most important time in your life.”

I’ve cited Josh Mitteldorf’s work about aging a few times. His paradigm of aging is in his 2017 book Cracking the Aging Code: The New Science of Growing Old – And What It Means for Staying Young that:

“Aging has an evolutionary purpose: to stabilize populations and ecosystems.”

However, there isn’t evidence of such causal inheritance mechanisms that would begin an organism’s aging during embryogenesis, i.e., that an embryo’s development of aging elements at gastrulation is causally affected by population and ecosystem factors.

Dr. Goodenowe recently had a casual conversation Episode 8 – Perpetual Health, Exploring The Science Behind Immortality where he asserted items such as:

“What we’re all fighting is entropy. Entropy is the tendency of all things to reach a level of randomness. Aging is not a disease. It’s just apathy and entropy. The body just doesn’t care – people don’t pay attention.

This notion that we are programmed for death is wrong. We’re not programmed to die. We actually teach ourselves to die. The body learns how to die, so as your function decreases, it adjusts. It appears to be programmed because of the association with chronological age.”

I haven’t seen any of his papers that put these and his other assertions up for review. For example, I doubt the entropy-caused randomness assertion would survive peer review per Stochastic methylation clocks?:

“Entropic theories of aging have never been coherent, but they are nevertheless experiencing a resurgence in recent years, primarily because neo-Darwinist theories of aging are all failing. I find this ironic, because the neo-Darwinist theories arose precisely because scientists realized that the Second Law of Thermodynamics does not apply to living systems.”

The funny thing about failed aging paradigms is that quite a few of their treatments improve healthspan, but not lifespan. If they don’t “target aging underlying mechanisms” they “ameliorate aging phenotypes.” None so far have positively affected both human healthspan and lifespan.

Activate Nrf2 to reduce biological age

September 22, 2024November 13, 2024 gettingwell4 4-5 stars Advanced knowledge, Anterior cingulate cortex, Brainstem, Cerebellum, Cerebrum, Epigenetics, Glutamate, Hippocampus, Immune system, Limbic system, Lower brain, Memory, Neurochemicals, Stress Control group, DNA methylation, Neural plasticity, Neurodegenerative disease, Prefrontal cortex

A 2024 primate study investigated effects of an off-patent drug on age-related changes:

“We evaluated geroprotective effects of metformin on adult male cynomolgus monkeys. The study encompassed a comprehensive suite of physiological, imaging, histological, and molecular evaluations, substantiating metformin’s influence on delaying age-related phenotypes at the organismal level.

Results highlighted a significant slowing of aging indicators, notably a roughly 6-year regression in brain aging. Metformin exerts a substantial neuroprotective effect, preserving brain structure and enhancing cognitive ability.

Geroprotective effects on primate neurons were partially mediated by activation of Nrf2, a transcription factor with anti-oxidative capabilities.”

https://www.cell.com/cell/abstract/S0092-8674(24)00914-0 “Metformin decelerates aging clock in male monkeys” (not freely available). Thanks to Dr. Pradeep Reddy for providing a copy.

From this study’s Nrf2 activation findings:

“Metformin treatment resulted in increased nuclear phosphorylated Nrf2, accompanied by up-regulation of Nrf2 target genes like HO-1, NQO-1, SOD3, GPX2, and GPX1, which were generally suppressed and typically down-regulated during human neuron senescence.

Genes pivotal for neuronal function, such as dendrite morphogenesis/extension and synapse assembly (e.g., GSK3B, GRID2, and NRG3), were down-regulated during aging in excitatory neurons (ExN), inhibitory neurons (InN), oligodendrocytes (OL), oligodendrocyte progenitor cells (OPC), microglia, and astrocyte but were restored by metformin treatment. By contrast, pathways that were up-regulated during aging, including activation of the immune response, complement activation, and regulation of the TGF-b receptor signaling pathway, were reset to lower levels by metformin treatment.

We verified that markers associated with brain aging and progression of neurodegenerative diseases were restored by metformin treatment to levels similar to those observed in young monkeys. Additionally, we observed that reduced myelin sheath thickness, a characteristic of aged monkeys, was rebuilt to a younger state following metformin treatment.

These findings align with the levels of nuclear-localized phosphorylated Nrf2, suggesting that Nrf2 pathway activation is a key mechanism in metformin’s role in delaying human neuronal aging and, by extension, brain aging. Consistent with our in vitro findings, Nrf2 pathway activation was also detected across multiple tissues in metformin-treated monkeys, including frontal lobe neurons.

At last count, I’ve curated 250+ papers this decade on cruciferous vegetables, and many of these explored relationships with Nrf2 activation. Basically, eating a clinically-relevant daily dose of 3-day-old cruciferous sprouts and taking off-patent metformin both induce Nrf2 activation effects.

Don’t expect to see many researchers highlighting this equivalency. They’d rather wait another decade to nitpick other studies with not-enough-subjects / not-exactly replicated / other nitpicks before expressing opinions urging caution from their nursing home beds.

But even then, they won’t get their facts straight. For example, a contemporaneous opinion article https://www.nature.com/articles/d41586-024-02938-w “The brain aged more slowly in monkeys given a cheap diabetes drug” attempted to summarize this study, and flubbed two points:

1. The study said: “We conducted a proof-of-concept study involving male cynomolgus monkeys (Macaca fascicularis) aged between 13 and 16 years, roughly equivalent to approximately 40–50 years in humans. Monkeys adhered to this regimen for a period of 1,200 days, approximately 3.3 years, which corresponds to about 10 years in humans.”

The opinion claimed: “Animals took the drug for 40 months, which is equivalent to about 13 years for humans.”

2. The opinion quoted a New York City researcher involved in a separate metformin study and employed at a medical school for:

“Research into metformin and other anti-ageing candidates could one day mean that doctors will be able to focus more on keeping people healthy for as long as possible rather than on treating diseases.”

This statement is a big break from the realities of medical personnel daily actions at least so far this decade, which is when I started to pay close attention:

Doctors have very little diet and exercise training in medical school. There’s no way they can give health advice. There’s no way that a “keeping people healthy” paradigm will emerge from the current medical system.
Fixing a disease doesn’t restore a patient’s health. Dr. (PhD) Goodenowe cites several examples in his talks, such as a study that compared colorectal cancer therapy with post-operation patient health.
If you listen to yesterday’s two-hour-long podcast, the currently injured person in the first hour gave plenty of contrary evidence of doctors’ focuses: behaviors of trying to blame and gaslight the patient, thinly-disguised punitive actions, CYA etc., all of which they will be sued for one day. The doctor in the second hour provided an example of the quoted researcher in her explanation of how doctors higher in the hierarchy either can’t see or can’t admit realities of doctor/patient interactions, and what therapies have actually benefited or harmed a patient.