Metformin Offers No Strength Training Benefits for Seniors, Study Shows

A study in Aging Cell found the diabetes drug metformin did not help exercising seniors build muscle mass, reports ScienceDaily . Older adults who took metformin while engaged in rigorous resistance training had smaller increases in muscle mass compared to a placebo group. University of Kentucky Professor Charlotte Peterson said metformin's anti-inflammatory properties made it seem a logical choice, as chronic inflammation in muscles may influence the ability to increase muscle mass. "In older adults age 65 and up who have lost significant muscle mass and function over prior decades, we thought metformin might combat muscle inflammation and thereby boost the muscle regrowth response to resistance training," explained University of Alabama at Birmingham Professor Marcas Bamman. "Instead, metformin impaired the adaptations such that the placebo group experienced greater increases in muscle mass and muscle quality than the metformin group." It was originally theorized that metformin would alter macrophage metabolism into a reparative phenotype by triggering a kinase called AMPK, but Peterson noted AMPK also represses mTORC1, a key muscle growth regulator. "Metformin's inhibition of that pathway is likely the reason that the metformin group did not see the same gains in muscle mass as the control group," she concluded.