Metformin (Glucophage) is currently a popular drug prescription for treating Type 2 Diabetes and Polycystic Ovary Syndrome. However 3 clinical trials from Chinese researchers suggest that Berberine, a substance found in several plants and historically used medicinally, is as good or better than Metformin. Summaries of the 3 studies and their references are listed below.
I came across this set of research articles investigating PCOS and thought it offered insight into the history of the research and some of the important findings. These articles are all freely available.