Just search Hacker News for metformin: it is actually discussed quite a lot, and there are tons of posts about this effect (whether it is actually true or not I

Just search Hacker News for metformin: it is actually discussed quite a lot, and there are tons of posts about this effect (whether it is actually true or not I don't know, but like: the citations you seek are extremely easy to find if you just take a few seconds to look).