I've been on metformin for 4 months, and haven't lost any weight- how many mg are you on? I take 1000mg/day. I haven't gained any weight either, which is good, but I wouldn't have minded a loss ;) We're ttc, so maybe it has something to do with the clomid. I've had some bad side effects to the metformin- I take one dose at night, with the idea of sleeping through it, but a few times I've woke up with nausea and gotten sick.