Metformin

The cheap diabetic drug with a complicated longevity narrative.

For a decade, Metformin was the darling of the anti-aging community based on retrospective epidemiological data suggesting diabetics on Metformin lived longer than non-diabetics, and even longer than matched non-diabetic controls.

Mechanism

Metformin acts as a mild mitochondrial toxin, inhibiting Complex I of the electron transport chain. This decreases ATP production, increasing the AMP/ATP ratio, which activates AMPK (the cellular energy sensor). AMPK activation mimics fasting, shutting down mTOR and promoting autophagy.

The Changing Consensus

Recent data has tempered enthusiasm for Metformin in young, metabolically healthy individuals:

• Exercise Blunting: Studies have shown Metformin blunts the hypertrophic (muscle-building) and aerobic adaptations to exercise. If you lift weights to build muscle, Metformin works against you.
• ITP Results: Metformin showed very modest (and sex-specific) lifespan extensions in the ITP, nowhere near Rapamycin.

The TAME Trial

The Targeting Aging with Metformin (TAME) trial aims to establish clinical endpoints for aging itself. While scientifically important, many clinicians have already moved on from Metformin as a primary longevity agent for non-diabetics.

Verdict

Excellent for those with insulin resistance or pre-diabetes. Likely net-negative for metabolically healthy individuals who exercise vigorously.