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Metformin

Metformin is an established type 2 diabetes drug. Its diabetes outcomes do not establish healthy-human lifespan, healthspan, cognition, or muscle benefit, and randomized geroscience trials have been null or unfavorable on their primary claims.

tier D · focus · 0.001 m/s MET-PREVENT walking-speed difference

verdict

UKPDS supports selected long-term outcomes in overweight people with newly diagnosed type 2 diabetes. MASTERS, MET-PREVENT, and METFORAGING do not establish a general healthy-aging benefit.

the core tension

Metformin has important diabetes evidence and familiar pharmacology. Diabetes outcomes do not establish general healthy aging, and the direct randomized muscle, function, and aging-biomarker trials do not repair that claim gap.

what it is

US tablets contain metformin hydrochloride, whose mass differs from metformin free base. Immediate-release tablets and extended-release products are not interchangeable exposure records, and fixed combinations add another active drug.

what it does

Metformin lowers hepatic glucose production, decreases intestinal glucose absorption, and improves insulin sensitivity without stimulating insulin secretion. Those glucose-lowering actions do not prove slower biological aging.

origin

The current immediate-release label was revised April 2026 and covers glycemic control in type 2 diabetes, not lifespan, healthspan, cognition, dementia prevention, or prophylactic use in healthy people.

does it work

For its diabetes indication, yes. In geroscience-oriented trials, metformin blunted resistance-training hypertrophy in MASTERS, had a null walking-speed endpoint and worse tolerability in MET-PREVENT, and had a null week-96 epigenetic-age endpoint in METFORAGING.

key facts

  • molecular formula: C4H11N5 free base; C4H12ClN5 hydrochloride
  • molecular weight: 129.16 g/mol free base; 165.62 g/mol hydrochloride
  • amino acids: n/a (small-molecule biguanide)
  • half-life: about 6.2 h in plasma and 17.6 h in blood in the immediate-release label record
  • type: metformin free base with a distinct hydrochloride drug-substance mass
  • CAS: 657-24-9 free base; 1115-70-4 hydrochloride
  • 109 / 94 MASTERS randomized and analyzed populations
  • 0.001 m/s MET-PREVENT primary walking-speed difference
  • 40 / 35 METFORAGING randomized and per-protocol populations

frequently asked questions

Is metformin approved for longevity?

No. The April 2026 immediate-release label covers type 2 diabetes and does not include lifespan, healthspan, or healthy-aging use.

What did MASTERS show?

MASTERS randomized 109 and analyzed 94 after a 2-week drug-only ramp plus 14 weeks of resistance training. Metformin blunted hypertrophy, and its corrigendum did not change the lean-mass conclusion.

Was MET-PREVENT positive?

No. MET-PREVENT had a null walking-speed primary endpoint, 108 versus 77 adverse events, and hospitalizations in 12/35 versus 3/36 participants, supporting a worse tolerability boundary.

Did every METFORAGING participant take the study drug twice daily?

No. Exposure began once daily, and 11 metformin participants taking dolutegravir remained once daily. The primary per-protocol analysis used 35 of 40 randomized participants.

Did METFORAGING slow epigenetic aging?

Its week 96 primary PhenoAge endpoint was not significant in a specific HIV population, and drug-free follow-up remains ongoing. It did not establish lifespan or clinical healthspan benefit.

related peptides

  • Rapamycin: The metformin evidence cited on this page does not establish rapamycin's identity, mTOR pharmacology, mouse lifespan result, or human aging outcomes.

reptides grades the research record and cites the literature behind every call. research reference only; not medical advice.