Metformin (drug for blood sugar) might make you smarter

I track my reaction time daily, and I was surprised to find that I got faster after I started taking metformin (brand name: Glucophage) for pre-diabetes. Reaction time is known to be correlated with cognitive ability, so it's possible that metformin may have nootropic properties. The drug is also reported to have other benefits, such as increasing longevity and preventing neurodegenerative diseases.