Metformin for longevity
Clinical reviewer: Jacob Moore, MD · Last checked September 22, 2026
What is metformin used for in longevity?
Metformin for longevity refers to using metformin, a biguanide FDA-approved only for type 2 diabetes, off-label in hopes of slowing aging. The idea traces to observational studies showing diabetics on metformin sometimes outlived people without diabetes, prompting researchers to propose a dedicated aging trial. Whether that protective effect holds in people who do not have diabetes remains actively disputed.
What is metformin FDA-approved for?
Metformin is a biguanide "indicated as an adjunct to diet and exercise to improve glycemic control in adults and pediatric patients 10 years of age and older with type 2 diabetes mellitus" [1]. It carries a boxed warning for lactic acidosis [1]. FDA has not approved metformin for slowing aging or extending lifespan in people without diabetes; any such use is off-label.
Why do some researchers study metformin for longevity?
A 2016 paper notes metformin "has demonstrated protective effects against several age-related diseases in humans" and describes plans to test it "in the TAME (Targeting Aging with Metformin) trial, as the initial step in the development of increasingly effective next-generation drugs" [2]. That is why an already-approved drug is discussed as a candidate for aging research, despite having no such approval itself.
Is metformin's anti-aging effect settled?
No. A 2025 review concludes that after re-examining the early influential findings and their replication attempts, the field shows "an emerging uncertainty in the anti-aging potential of metformin" [3]. Supporting that caution, a randomized trial in adults around 62 years old (27 on metformin, 26 on placebo) found that during 12 weeks of aerobic exercise training, "metformin attenuated the increase in whole-body insulin sensitivity and VO2 max," and also blunted the usual exercise-driven rise in skeletal muscle mitochondrial respiration [4].
Related terms
Sources
- Metformin Hydrochloride Tablets Prescribing Information, DailyMed
- Barzilai N et al. Metformin as a Tool to Target Aging. Cell Metabolism, 2016.
- Keys MT et al. Emerging uncertainty on the anti-aging potential of metformin. Ageing Research Reviews, 2025.
- Konopka AR et al. Metformin inhibits mitochondrial adaptations to aerobic exercise training in older adults. Aging Cell, 2019.
This entry is for education and is not medical advice. Talk with a licensed clinician about your own situation before starting, stopping, or changing any treatment.
