https://www.reddit.com/r/Futurology/comments/6w4bmy/we_might_all_be_taking_a_cheap_drug_called/ "He has maintained this confidence ever since he read a 2014 study that reviewed the fate of 90,400 type 2 diabetics taking either metformin or another medication. The metformin patients in the study not only outlived the diabetics taking the other drug—a not especially surprising result if metformin is a superior treatment—but also outlived the nondiabetics studied as a comparison." "My Grandma started metformin 10 years ago, she will be 85 next weekend while all her siblings have passed. She is sharp as a blade and completely independent and good health." "Good, approachable review of the spotty data here. Certainly, better than the worshipful tone of the cited text. The mode of action of Metformin is imperfectly known. Overview here. In the liver, it activates AMP-activated protein kinase. AMPK has a whole host of roles, but one is as the 'fuel gauge' monitoring system of cellular energy status. It plays a crucial role in protecting cellular functions under energy-restricted conditions. However, Metformin also has impacts on lipid metabolism, eg reversing hepatic steatosis. It both increases fat burning and reduces its synthesis in the liver, perhaps through AMPK, perhaps not. Quite separately, it seems to condition heart muscle cells to regenerate after ischaemia (blocked blood flow) and cardiac deaths are reduced in patients who take the drug. Interesting that aspirin also stimulates AMPK production."