This 2020 meta-analysis subject was DHEA:
“Twenty-four qualified trials were included in this meta-analysis. Statistically significant increases in serum IGF-1 levels were found only in participants who were:
- Women; or
- Supplementing 50 mg/d; or
- Undergoing intervention for > 12 weeks; or
- Without an underlying comorbidity; or
- Over the age of 60 years.
DHEA supplementation led to an overall increase of ~16 ng/ml in serum IGF-1 levels, as well as increases of ~23 [women] and ~20 ng/ml [age > 60]. Diseased and healthy subjects ages ranged from 20 to 72 years old.”
Discussion section explanations of the above:
- “Women are more susceptible to biochemical and clinical shifts caused by DHEA supplementation.
- The majority of investigations tested DHEA at a dose of 50 mg/d.
- The majority of studies were performed for > 12 weeks.
- Participants with no comorbidities were also older in many studies.
- Older patients have a natural decline in the production of IGF-1 and DHEA.
Additional rigorous RCTs are warranted to better define whether and to what extent changes in IGF-1 levels caused by DHEA supplementation are relevant for health benefits.”
https://www.sciencedirect.com/science/article/abs/pii/S0531556520302977 “Impact of dehydroepian[d]rosterone (DHEA) supplementation on serum levels of insulin-like growth factor 1 (IGF-1): A dose-response meta-analysis of randomized controlled trials” (not freely available)
More on IGF-1 from The influence of zinc supplementation on IGF-1 levels in humans: A systematic review and meta-analysis which was cited for “Previous studies have demonstrated that IGF-1 levels can be affected by several factors.”
“IGF-1 is a growth factor synthesized in the liver, and elicits a myriad of effects on health due to its participation in the GH-IGF-1 axis, where it:
- Is involved in tissue homeostasis;
- Has anti-apoptotic, mitogenic, anti-inflammatory, antioxidant and metabolic actions;
- Contributes to skeletal muscle plasticity, maintenance of muscle strength and muscle mass;
- Neural and cardiovascular protection;
- Development of the skeleton;
- Possesses insulin-like effects, and
- Is a key factor in brain, eye and lung development during fetal development.
IGF-1 plays important roles in both growth and development, and its levels vary depending on age, with peaks generally observed in the postnatal period and at puberty. IGF-1 levels influence the release of GH [growth hormone] from the hypophysis [pituitary gland] via a negative feedback loop.
A rapid decrease in IGF-1 levels is registered during the third decade of life. Levels gradually decrease between the third and the eighth decade of life.”
The Group 3 “> 12 weeks” finding was reinforced by perspectives such as:
- Eat broccoli sprouts for your hair! “The potential benefit of taking a geroprotector may come after a long period.” and
- Reviewing clinical trials of broccoli sprouts and their compounds “Biomarkers of effect need more time than biomarkers of exposure to be influenced by dietary treatment.”
Group 4 “with no comorbidities” was narrowly defined. All of us have degrees of diseases in progress. Consider aging effects:
- Aging as a normal disease “Aging and its diseases are inseparable, as these diseases are manifestations of aging. Instead of healthy aging, we could use the terms pre-disease aging or decelerated aging.”
- Aging as an unintended consequence “Epigenetic ageing begins from very early moments after the embryonic stem cell stage and continues uninterrupted through the entire lifespan. Ageing is an unintended consequence of processes that are necessary for development of the organism and tissue homeostasis thereafter.”
- Organismal aging and cellular senescence “If we assume that aging already starts before birth, it can be considered simply a developmental stage, required to complete the evolutionary program associated with species-intrinsic biological functions such as reproduction, survival, and selection.”
- An environmental signaling paradigm of aging “The age-phenotype of a cell or organ depends on its environment and not its history. Organisms, organs, and their cells can be reset to different age-phenotypes depending on their environment.”
These perspectives are less important than what each of us choose to do about our own problems. Take responsibility for your one precious life.