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Metformin (Glucophage)
A first-line type-2-diabetes drug (Glucophage) studied as a geroprotector and the basis of the TAME longevity trial. The human longevity case rests on diabetic-population epidemiology and one large meta-analysis; it is genuinely contested — including evidence it can blunt exercise adaptations. A prescription drug taken off-label, not a supplement.
Prescription medication — not a dietary supplement
Metformin is a prescription (or investigational) drug, not a supplement. It is included here for reference because people research and discuss it (often used off-label) — not as a recommendation. Take it only under a qualified clinician's supervision and only as prescribed; do not source it from grey-market vendors, where identity, purity, and dosing are unverified. The evidence below reflects its clinical trials.
What the evidence says
Metformin doesn't have enough studies with structured effect-size data yet to pool a verdict. Browse the studies below for individual findings.
Most evidence is from high-quality meta-analyses and randomised trials published 1998–2026 with a typical study size of 753 participants.
Based on 1,002 studies · 352 meta-analyses · 555 RCTs · 753 total participants
Confidence
High confidenceBy outcome
Metformin is a safe, effective diabetes drug with plausible aging mechanisms and supportive epidemiology, but its longevity benefit in non-diabetics is unproven (TAME has not reported) and genuinely contested — including randomized evidence that it can blunt exercise adaptations — so the geroprotector case stays emerging.
2,299 randomised trials
78% were about Metformin in an audit of 50 of them
Every randomised or controlled trial of Metformin indexed in PubMed, not a hand-picked subset. Meta-analyses and systematic reviews are deliberately excluded from this count: most of them cover many compounds at once, so counting them would inflate it.
PubMed · as of Sep 2026
370 trials ongoing or recruiting · NaN completed on ClinicalTrials.gov
685 of the completed trials have posted results
Registered trials show research momentum for Metformin, not proof of effect — a registration is a plan, and posted results are sponsor-reported, not peer-reviewed. They are never counted toward the evidence rating above.
Browse these trials on ClinicalTrials.govClinicalTrials.gov · as of Nov 2026
Showing the 1004 most recent of 2689 studies.
Metformin is a biguanide and the most-prescribed type-2-diabetes drug in the world.
Its appeal as a geroprotector comes from biology and epidemiology: it activates AMPK, mildly inhibits mitochondrial complex I, reduces hepatic glucose output, lowers insulin/IGF-1 signaling, and improves insulin sensitivity — all pathways linked to aging.
Some observational studies found diabetics on metformin had lower all-cause mortality than non-diabetics, and a frequently-cited meta-analysis reported reduced all-cause mortality and age-related disease.
This generated the landmark TAME (Targeting Aging with Metformin) trial concept — a proposed RCT to test whether metformin delays multiple age-related diseases in non-diabetics.
The honest picture is that the longevity case is contested and unproven in non-diabetics: the epidemiology is confounded (metformin-treated diabetics differ from comparators), TAME has not reported, and several lines of evidence temper enthusiasm — most notably randomized data that metformin can blunt the cardiorespiratory and muscle-hypertrophy adaptations to exercise training, and signals that it may attenuate some benefits of exercise in older adults.
As a drug it is well tolerated; the main issues are GI upset, vitamin B12 depletion over time, and (rarely) lactic acidosis in renal impairment. Metformin is a prescription drug; using it off-label for longevity in a non-diabetic is reasonable to discuss with a clinician but not evidence-established.
The score reflects strong drug-level data and plausible mechanisms against genuinely contested, unproven human longevity benefit and a real exercise-interference trade-off.
Metformin activates AMP-activated protein kinase, the cellular energy sensor, shifting metabolism toward catabolism/maintenance — overlapping with caloric-restriction signaling.
Mild inhibition of mitochondrial complex I raises the AMP:ATP ratio and reduces hepatic gluconeogenesis, lowering blood glucose and insulin.
Improved insulin sensitivity and lower circulating insulin reduce IGF-1-axis signaling, a pathway whose reduction extends lifespan in models.
How Metformin works — from molecular targets to health outcomes. Click an edge to see supporting research.This visualization is in beta — pathways are being refined and expanded.
Weigh the exercise-blunting evidence — metformin may attenuate training adaptations.
Dose-reduce or avoid; contraindicated below eGFR 30.
Discuss with a clinician — benefit is unproven.
Hold around contrast imaging in renal impairment — lactic-acidosis risk.
Heavy alcohol raises lactic-acidosis risk.
Tip: Contact your treating team about the symptom and follow the product-specific instructions. Do not reduce, split, stop or restart prescribed treatment solely to continue this experiment.
Tip: Monitor B12 on long-term use; supplement if low.
Tip: Avoid in significant renal impairment; very rare with normal kidney function.
Metformin has an evidence score of 4/10 — emerging evidence based on 2673 indexed studies, including 1 meta-analysis. A first-line type-2-diabetes drug (Glucophage) studied as a geroprotector and the basis of the TAME longevity trial. The human longevity case rests on diabetic-population epidemiology and one large meta-analysis; it is genuinely contested — including evidence it can blunt exercise adaptations. A prescription drug taken off-label, not a supplement. Representative study: PMID 28802803.
Dosing for Metformin: Off-label longevity use mirrors diabetes dosing (commonly 500–1500 mg/day of extended-release with meals) under a clinician. Not an approved longevity regimen, and unnecessary in well-controlled non-diabetics without a clear rationale. (a usual diabetes range, no cited trial states the dose it used). Individual needs vary, so check the right dose for you with a healthcare provider.
The best time to take Metformin is with meals. Take it with food. Taking with meals reduces GI upset; extended-release once daily improves tolerability.
Metformin should be used with caution — talk to a healthcare provider before taking it. Reported side effects include lactic acidosis, GI upset (diarrhea, nausea), vitamin B12 depletion. How often they occur is not established for all of them. Use caution if any of these apply to you: Severe renal impairment (eGFR < 30); Acute metabolic acidosis; Conditions predisposing to lactic acidosis (severe hypoxia, decompensated heart failure).
CoQ10
Likely helpsA lipid-soluble antioxidant central to mitochondrial energy production, with the strongest trial support for fertility/IVF outcomes and heart failure.
Berberine
Likely helpsActivates AMPK to regulate blood sugar, improve insulin sensitivity, and support lipid metabolism. Its only head-to-head trial with metformin cited here was a 36-person pilot, which does not show it can replace metformin.
Alpha Lipoic Acid
Likely helpsUniversal antioxidant that works in both water and fat, supporting blood sugar control, nerve health, and cellular energy.
Red Yeast Rice
Likely helpsFermented rice containing natural statins that effectively lower LDL cholesterol — the original statin.
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Reviewed by Dr. Baher Al Hakim · Last reviewed June 2026 · evidence from 2,689 studies · how we score · editorial policy
This information is for educational purposes only. It is not a substitute for professional medical advice. Always consult a qualified healthcare provider before starting, stopping, or changing any supplement or medication.
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