A Case of Unilateral Idiopathic Gynecomastia Aggravated by Low-Dose Finasteride (1 mg/Day, Propecia)
May 2004
TLDR Finasteride may cause breast enlargement in some men.
Low dose finasteride (1 mg/day, Propecia) was used as a treatment for male androgenetic alopecia, but a case was reported where it aggravated unilateral idiopathic gynecomastia. A 23-year-old man experienced painful enlargement of his right breast two months after starting the treatment. Upon discontinuation of finasteride, the symptoms disappeared after two months. This case highlighted a potential side effect of finasteride in the treatment of hair loss.