Continuing Part 1, here are four more 2025 human studies of the Nrf2 activator astaxanthin, starting with a randomized, double-blind, placebo-controlled trial of its effects on reducing oxidative stress and inflammatory responses following eccentric exercise:
“This study investigated effects of astaxanthin supplementation on plasma MDA and HMGB1 levels following acute eccentric exercise in recreationally active male students. Fifty-four students were assigned to receive either 12 mg/day of natural astaxanthin (AST, n = 27) or placebo (PLA, n = 27) for 14 days.
A key consequence of eccentric-induced muscle damage is overproduction of reactive oxygen species (ROS). When ROS production exceeds the capacity of endogenous antioxidant systems, lipid peroxidation can occur. Malondialdehyde (MDA) is a stable end-product of lipid peroxidation and serves as a widely recognized biomarker for oxidative stress and cell membrane damage.
In parallel, muscle cell damage results in release of damage-associated molecular patterns (DAMPs) into the extracellular space. Among these, High Mobility Group Box-1 (HMGB1) plays a central role in inflammation when passively released from the nucleus. HMGB1 acts as a potent pro-inflammatory signal by activating innate immune receptors, recruiting immune cells, and upregulating cytokines such as IL-6 and TNF-α.
This heightened immune activity contributes to delayed-onset muscle soreness, which typically peaks 24–72 hours post-exercise, and is associated with impaired recovery. Sustained elevations in oxidative and inflammatory biomarkers, including MDA and HMGB1, may further impair recovery and contribute to long-term muscle pathology.
Astaxanthin’s antioxidant effects are mediated through both direct and indirect mechanisms. Structurally, astaxanthin is a xanthophyll carotenoid with a unique polar–nonpolar–polar configuration that enables it to span the phospholipid bilayer of cell membranes. This positioning allows it to neutralize ROS both at the membrane surface and within the lipid bilayer.
In addition, astaxanthin enhances endogenous antioxidant defenses by upregulating enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx) through activation of the Nrf2–ARE signaling pathway. This dual mode of action provides both immediate and sustained protection against oxidative stress during and after exercise.
The placebo group showed substantial increases in MDA and HMGB1 after exercise, whereas the astaxanthin group experienced attenuated rises (~22% and ~27% smaller, respectively) and faster recovery toward baseline within 24 hours. These findings suggest that astaxanthin supplementation can be incorporated into recovery strategies for athletes and active individuals, especially during periods of heavy training or repeated bouts of intense eccentric exercise. By reducing oxidative damage and inflammation, astaxanthin may shorten recovery time, limit performance loss, and support overall training adaptations—benefits that are particularly valuable in sports requiring frequent high-intensity efforts.
Several limitations should be acknowledged in this study.
- Sample size was relatively small and limited to recreationally active young males, which may restrict generalizability of findings to other populations such as females, older adults, or elite athletes.
- Supplementation period was limited to 14 days; although this duration is sufficient to achieve plasma saturation of astaxanthin, longer interventions may produce different or more pronounced effects.
- Only two biomarkers were assessed (MDA and HMGB1), which provide important but incomplete insights into broader oxidative stress and inflammatory response. Including additional markers such as enzymatic antioxidants, cytokine profiles, and muscle damage indicators (e.g., creatine kinase) could yield a more comprehensive understanding.
- Dietary intake and physical activity outside the intervention were self-reported and not strictly controlled, which may have introduced variability in results.”
https://tmfv.com.ua/journal/article/view/3664/1922 “Taking Astaxanthin Supplementation Attenuates MDA and HMGB1 Following Eccentric Exercise: A Randomized Controlled Trial in Recreationally Active Students”
A clinical trial investigated astaxanthin’s effects with exercise in diabetic women:
“This study examined whether combined aerobic and resistance training (CT) and astaxanthin (AST) supplementation synergistically improve oxidant and inflammatory status as well as metabolic indices in T2DM, focusing on the mediatory role of Humanin (HN) and microRNAs (miRNA-122, miRNA-126-3p, and miRNA-146a).
Ninety women with T2DM were randomly assigned to six groups (n = 15 each):
- Control (C), placebo (P), AST supplementation (S), combined training (CT), CT + placebo (CT + P), and CT + AST supplementation (CT + S).
- CT, CT + P and CT + S groups underwent an 8-week training program (eight exercises, three sessions per week).
- S and CT + S groups received 8 mg/day of AST.
This study only enrolled female participants age between 30 and 60 years old to minimize inter-individual biological variability arising from sex differences in hormone regulation, fat distribution, and gene expression related to inflammation and oxidative stress. Oxidative stress (OS) markers, inflammatory cytokines, HN levels, miRNAs expression, fasting blood glucose (FBG), insulin resistance (HOMA-IR), lipid profile, and hemoglobin A1c (HbA1c) were assessed.
HN is a member of a class of novel mitochondrial-derived peptides released during mitochondrial dysfunction. HN reduces ROS production, enhances antioxidant protein expression, maintains redox balance, and suppresses TNF-α, IL-1β, and IL-6 to inhibit inflammation. Furthermore, resistance and endurance training has shown to increase HN expression in patients with prediabetes. Exercise – aerobic and endurance – has been shown to increase circulating and skeletal muscle levels of HN, correlating with improved insulin sensitivity and mitochondrial function.
Our results showed:
- CT and AST supplementation both improved antioxidant defense and reduced inflammation, and their combination was more effective than either intervention alone.
- CT and AST supplementation increased blood concentration of HN, and their combination showed greater effects than AST supplementation, but not CT.
- CT and AST supplementation increased blood levels of miRNAs-126-3p, and -146a and decreased miRNA-122, with their combination being slightly more effective in decreasing miRNA-122.
- Both interventions improved lipid profile, with their combination being more effective in improving HDL and TG levels, although not total cholesterol.
- FBG, HOMA-IR, and HbA1c were reduced by CT but not by AST supplementation.
Our data suggest that combining exercise with AST supplementation might improve oxidative status and inflammation through mechanisms involving HN and miRNAs 122, 126-3p, and 146a. Alleviating OS and inflammation could, in turn, lead to improvements in lipid profiles (e.g., TG, and HDL), IR, and reductions in HbA1c and FBG, as observed in our study. Furthermore, the combined approach seems to be more effective at improving cholesterol and TG levels.“
https://www.nature.com/articles/s41598-025-23914-y “Redox-sensitive miRNAs and Humanin could mediate effects of exercise and astaxanthin on oxidative stress and inflammation in type 2 diabetes”
A meta-analysis of randomized controlled trials reported until May 2025 assessed astaxanthin’s effects on lipid profiles. Neither of the two trials covered here nor the three trials covered in Part 1 were included in this meta-analysis.
“Astaxanthin, a xanthophyll carotenoid, has garnered significant interest due to its benefits with regard to dyslipidemia. This multifaceted functional food ingredient modulates several key enzymes associated with lipid regulation, including HMG-CoA reductase, CPT1, ACCβ, and acyl-CoA oxidase. It influences key antioxidant molecular pathways like Nrf2, limiting dyslipidemia occurrence and regulating liver cholesterol uptake through modulation of liver lipid receptors.
Astaxanthin daily doses and durations of analyzed studies: 12 mg for 8 weeks; 12 mg for 4 weeks; 20 mg for 12 weeks (two trials); 12 mg for 12 weeks; 8 mg for 8 weeks; 6 mg and 12 mg for 12 weeks; 6 mg, 12 mg, and 18 mg for 12 weeks.
This meta-analysis concludes positive effects of astaxanthin (6–20 mg/d) on HDL-C and triglyceride levels. Astaxanthin (6–20 mg/d) does not appear to significantly influence LDL-C and total cholesterol levels.
Regarding HDL-C, improvements were observed from 55 ± 8 mg/dL (pre-intervention) to 63 ± 8 mg/dL (post-intervention) (p < 0.01) in the 12 mg/d of astaxanthin groups. In triglyceride levels, results show a decrease from 151 ± 26 mg/dL (pre-intervention) to 112 ± 40 mg/dL (post-intervention) (p < 0.01) for 18 mg/d astaxanthin supplementation.
Further research is necessary to fully harness the potential of astaxanthin, which includes assessing astaxanthin in different subsets of patients, and in combination with other nutraceuticals to understand the compound’s effectiveness with regard to varying health conditions, genetic and epigenetic factors, and synergistic effects with other compounds.”
https://www.mdpi.com/1424-8247/18/8/1097 “Assessing the Effects of Moderate to High Dosage of Astaxanthin Supplementation on Lipid Profile Parameters—A Systematic Review and Meta-Analysis of Randomized Controlled Studies”
This same group of researchers assessed that in nine RCTs, astaxanthin had no effects on either body weight or BMI per https://www.mdpi.com/1424-8247/18/10/1482 “Therapeutic Potential of Astaxanthin for Body Weight Regulation: A Systematic Review and Meta-Analysis with Dose–Response Assessment”





































