Unveiling the Hidden Brain Effects of Long-Standing Diabetes Drug Metformin
Scientists have just rewritten what we know about one of the world’s most prescribed medications. Researchers at Baylor College of Medicine, working with international collaborators, have discovered that the diabetes drug metformin — trusted for over 60 years — also works directly in the brain to lower blood sugar, through a mechanism that had gone entirely unrecognized until now.
Published in the journal Science Advances, the study identified a small protein called Rap1, located in a region of the brain known as the ventromedial hypothalamus (VMH). The team found that metformin’s ability to lower blood sugar at clinically relevant doses depends on suppressing Rap1 activity in this area — activating specific neurons that help regulate glucose. Remarkably, even tiny doses of metformin injected directly into the brains of diabetic mice produced a marked reduction in blood sugar.
This finding has major implications. Most diabetes drugs do not target the brain at all, yet metformin appears to have been quietly doing so for decades. Scientists now believe this newly uncovered brain pathway could help explain the drug’s wide range of observed health benefits — including potential anti-aging effects on the brain itself.
“It’s not just working in the liver or the gut, it’s also acting in the brain,” said lead researcher Dr. Makoto Fukuda, associate professor of pediatrics and nutrition at Baylor College of Medicine. The research opens the door to more targeted diabetes therapies and could eventually lead to more potent, optimized versions of metformin.
Source: ScienceDaily – After 60 Years, Scientists Uncover Metformin’s Hidden Brain Effects (2026)