I have a condition called PCOS (poly-cystic ovarian syndrome) and metformin is commonly used to help treat it (for a couple of reasons but one includes that those with PCOS are higher risk for diabetes). Well, I'm not really overweight but I wanted to lose about 10 more pounds that weren't coming off with diet and exercise - my doctor gave me metformin to see if it would help. For the record it didn't really, but since I wasn't overweight to start with, that might have been why.