The most commonly reported effects are mild: lightheadedness or headache, slight swelling of the ankles or feet, unwanted hair growth on the face or body, and a temporary increase in shedding during the first weeks as follicles cycle. A small percentage of men taking finasteride report sexual side effects such as decreased libido or erectile difficulty, which usually resolve after stopping. Mood changes and breast tenderness or lumps should be reported to your clinician promptly. Review the full Important Safety Information before starting.