The apparent reductions in mortality from all causes put together in diseases of aging,

associated with metformin use,

suggests that the drug metformin could be extending life and health spans by acting as a

gyrot protective or anti-aging agent.

What might the downsides be?

Gastrointestinal side effects such as flatulence, indigestion,

abdominal discomfort, relatively common.

More than half, starting metformin, report diarrhea, for example,

and a quarter experienced nausea or vomiting.

About 10% unknowingly taking the placebo will report similar symptoms, though, so the actual

proportion of people suffering such symptoms due to the drug is probably more like one

and three.

Most of these effects tend to be transient, though, and can be minimized by taking metformin with food and starting

at a suboptimal dose, increasing gradually to target over a period of weeks.

Once a day, extended release versions also tend to be more tolerable.

The most dreaded side effect, though, is lactic acidosis, the potentially fatal build-up

of acid in the blood.

I mean, poisoning of the mitochondria is kind of the whole point.

That's what activates AMPK, but it's supposed to be a mild mitochondrial poison, but sometimes

it evidently poisons a bit too much.

Thankfully, metformin-induced lactic acidosis is extremely rare.

It has a fatality rate of 50%, but only occurs at a rate of about 0.03 cases per thousand patient years.

...