Hi @timide, welcome to the community. I caution about using statements like "this is not true" without knowing the full background. Everyone is different.

By the same token, @queenie2030, a drug that might be dangerous for one person, might be very safe for someone else.

I found useful information from Harvard Medical School that underlines how you can both be right. 🙂

- Is metformin a wonder drug? https://www.health.harvard.edu/blog/is-metformin-a-wonder-drug-202109222605

See specifically this excerpt:
"The safety profile for metformin is quite good. Side effects include nausea, stomach upset, or diarrhea; these tend to be mild. More serious side effects are rare. They include severe allergic reactions and a condition called lactic acidosis, a buildup of lactic acid in the bloodstream. The risk for this is higher among people with significant kidney disease, so doctors tend to avoid prescribing metformin for them."

So people with kidney disease should be aware of the contraindication. For others, metformin is the drug that works.

Timide, how long have you been taking metformin? Do you tolerate it without side effects?