Unilateral Gynecomastia Induced by Treatment With 1 mg of Oral Finasteride
 March 2001   
in “
 Archives of Dermatology 
”
 
      
   TLDR  Finasteride can cause one-sided breast enlargement, which disappears after stopping the drug.   
  This document reports on four cases of unilateral gynecomastia induced by treatment with 1 mg of oral finasteride, a drug commonly used to treat male pattern hair loss. The breast enlargement disappeared between 2 to 10 months once use of the drug was discontinued. The authors suggest that new studies are needed for better knowledge of the real incidence of this adverse effect of the drug.
    
  