Metformin decelerates aging clock in male monkeys

Mechanisms and relation to diet

• Metformin is described as reducing liver glucose production, increasing insulin sensitivity, and raising GDF15, which suppresses appetite and caloric intake.
• Some argue its aging effects may largely mimic calorie restriction and weight loss rather than being unique.
• Others emphasize AMPK–mTORC1 inhibition, autophagy, and broader “starvation mimetic” effects beyond weight control.
• Several comments link high sugar/carbohydrate intake to metabolic and brain damage, with low‑carb or ketogenic diets cited as reversing type 2 diabetes in some individuals.

Evidence for/against longevity and aging effects

• The primate study is seen as promising because it addresses earlier doubts based on nematode/mouse data.
• Critics note mouse Interventions Testing Program results: weak or no lifespan benefit from metformin alone, versus strong effects from rapamycin.
• A twin-cohort human study is cited as finding no reduction in all‑cause mortality from metformin; earlier claims that diabetics on metformin outlive non‑diabetics are called implausible.
• Some stress that the new paper focuses on “aging clock” and brain atrophy, not proven lifespan extension.

Side effects and safety concerns

• Common reports: significant gastrointestinal distress (sometimes months), diarrhea, “emergency” bathroom needs; some find tolerance improves with gradual introduction.
• Mentioned risks: gastroparesis, metformin‑associated lactic acidosis (potentially high mortality), possible male genital birth defects when taken around conception, and possible cognitive/mood effects in some users.
• Routine monitoring is described as important due to potential accumulation.

Dosing, trials, and access

• Monkey dose ~20 mg/kg/day is mapped to common human doses (up to ~2,000 mg/day) already used for diabetes.
• The TAME aging trial is discussed; it has regulatory green lights but funding problems, allegedly because metformin is off‑patent and not very profitable.
• Users on high‑dose generic metformin report low cost and good access; concern exists that “longevity hype” could affect pricing, but others note it is old and easy to manufacture.

Comparisons to rapamycin, GLP‑1 drugs, fasting

• Several argue low‑dose, intermittent rapamycin/rapalogs are more potent and better‑supported mTORC1 inhibitors with strong mouse longevity data.
• GLP‑1 agonists are framed as powerful, scalable obesity and addiction treatments, with debate over societal implications and psychological side effects.
• Intermittent fasting is linked mechanistically to mTOR/autophagy, but a cited (not peer‑reviewed) abstract claiming higher cardiovascular mortality with short eating windows is viewed as likely confounded and methodologically weak.

Healthspan vs lifespan and philosophy of aging

• Many distinguish “living longer” from “aging slower,” emphasizing preserved cognition, function, and delayed disease over mere extra years.
• The primate finding of reduced brain aging is seen as especially important given dementia concerns.
• A long subthread debates whether extending life is desirable: some want more time to experience and learn; others, influenced by seeing severe dementia, prioritize a clean, timely death.
• Some frame extended healthy life as a continuation of civilization’s longstanding effort to transcend “natural” mortality, while critics raise concerns about resource competition, inequality, and extended years of work.

Methodological and species concerns

• Participants note contradictions between species (mice vs monkeys vs humans) and caution against over‑generalizing.
• Small sample sizes (e.g., ~12 monkeys), heavy bioinformatics, and lack of large randomized human trials are cited as reasons for skepticism.
• One commenter flags a general need for caution with studies originating from specific countries, including China.

Open questions and unresolved points

• Whether metformin’s main benefit for aging is through metabolic disease reduction, direct mTOR/AMPK effects, or other pathways remains unclear.
• It is unknown if metformin offers net longevity/healthspan gains in non‑diabetics, especially given mixed human and mouse data.
• Fasting/time‑restricted eating as a metformin alternative or complement is discussed but not resolved; evidence is viewed as mixed and confounded.
• A patient with neuroendocrine tumors asks about combining metformin with everolimus based on a cancer paper; no concrete structures or tools for patient‑organized trials are provided in the thread.