This seems to require a prescription in the USA so may I assume you are not in the USA?

Or they just have a off-label prescription.

I have a prescription. I just asked my doctor and showed them a few papers I was reading and they wrote a prescription.

Because of its safety and cost, they didn’t really care.

I did the same. “Why? Sure, knock yourself out, hope it helps.”

Thanks, I was not aware this was possible.

Has it extended your life?

Yes?

I guess it hasn't killed him yet.

Or even caused any debilitating side effects.

They're still alive, so we can probably assume it's causal.

I suppose I’ll never really know since there’s not a me that’s not taking it.

But it’s less than a dollar a month and doesn’t have any negative effects so I’m comfortable risking it has no effect.

you are aware that metformin is used to treat type 1 diabetes?

Yes, of course.

It's mostly used for type 2 diabetes, not type 1.

Medicine is funny that way; if you allocute to taking some sort of medication then they will readily extrapolate that to a diagnosis. For example, my PCP had recently prescribed me some meds for no good reason. She had not ruled out other causes of a thing and she lied about the lack of side effects, so the prescription was written. Then when I entered the hospital within a few weeks, I informed them of the prescription and they immediately placed on my chart a diagnosis for the thing treated by that drug. I am confident that I do not have, and never had, the disorder they "diagnosed" me with. The hospital ran no tests and was frankly incapable of such a diagnosis on their own, so the only information they used was my verbal assertion that I was taking this drug. They didn't even see proof from my PCP. So be very careful about what you fill out in those medical histories, and be careful with your releases of HIPAA information, because they will get extrapolated and haunt you for a very, very long time.