polycystic ovary syndrome
"I was diagnosed with PCOS in 2013 but did not start taking Metformin seriously until late 2014.  I am also prediabetic, which is what has jump started my desire to seriously lose weight.  I cannot speak for blood sugar levels as I have not had them rechecked, nor have I gotten my cycle back, but I also have a significant amount of weight to lose first.  I definitely experience upset stomach and pretty intense diarrhea; however, this only seems to happen if I do not watch my carb and/or sugar intake.  If I eat sensibly, I have little to no issues in the side effect department.  I am losing weight and moving more, and hope to one day not need medication anymore."