What is metformin?
Metformin is a widely used, inexpensive prescription drug for type 2 diabetes that lowers blood sugar mainly by reducing how much sugar the liver releases.
Think of your liver as a sugar warehouse that keeps shipping sugar into your blood. Metformin turns down the shipping rate, so less sugar floods the bloodstream.
Why it matters for aging
Metformin has been used for decades and has a long safety record. Common side effects are stomach upset and, over the long term, lower vitamin B12 levels, which doctors can check.
Longevity researchers became interested because it activates AMPK, the cell's fuel gauge, and because of early data suggesting people with diabetes on metformin lived surprisingly long. A large trial to test it as an anti-aging drug has been planned for years. Until then, its anti-aging role is unproven.
A common myth
Metformin is a proven anti-aging drug that everyone should take.
It's a proven diabetes drug. Its longevity reputation rests largely on one observational study that a later analysis didn't confirm, and in older adults it blunted the fitness benefits of exercise training.
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Updated Nov 9, 2026 · All terms