Proscar (finasteride) can cause gynecomastia
Physicians are being alerted that Proscar (finasteride) can cause gynecomastia.
In fact, FDA staffers say that breast enlargement is the MOST frequently reported adverse effect they receive for Proscar. The risk is about 4 cases per 1000.
Gynecomastia can occur within a few weeks of therapy...or years later. It's probably caused by an imbalance between testosterone and estrogen.