I've been on metformin (1500mg per day) for about 8 months. After getting off the pill I had no periods for 3 months before my doctor gave me provera to induce my period before starting metformin. I bled almost immediately after starting to take it and after about 3 months my cycles have been consistently 45 days. Not perfect, but at least it's fairly consistent.It did make me pretty nauseous when I first started and I had diarrhea a few times but the nausea eventually subsides and the diarrhea was usually due to dehydration. Stay hydrated and don't take it on a completely empty stomach.I'm still waiting on a bfp but ovulation is becoming easier to actually predict. Changing my diet and lowering my stress probably helps, too. Good luck!