Metformin
"Started my period when I was 11, went through cycles like a normal pre-teen, and then when I was 13 my period stopped.  After a few months I mentioned it to my pediatrician, who referred me to an OBGYN, and then a pediatric endocrinologist.  Because I was so young, I chose to forgo BC and do metformin, started out at 500mg/day. Lost 40 pounds and felt great, periods came back to every 35-40 days.  However, after a while, the medication stopped working and I was put up to 1000mg, then eventually 1500mg.  Once I was older I switched to BC because the metformin stopped working.  Liked that I lost a lot of weight in the beginning, but then it just stopped.  I'm on it again now after 3 years to lower my free testosterone, and it's ok."