This question is not exactly about Diabetes, but because metformin HCL is used in Diabetes treatment, I would like to know of any of you has experience with this medicine. Can you tell me about its side effects? Recently I went for a checkup and my doctor gave me Metformin for weight loss (It suddently went up to 99 kg though I was at 85 before and was following a strict diet plan). I don't have diabetes and I haven't been diagnosed with PCOS, and I think Metformin is generally used for these two issues. So I'm concened whether I should really be Metformin. Can it mess up my insulin system?