Overview
Propecia is approved by the U.S. Food and Drug Administration (FDA) for the treatment of androgenetic alopecia in men only, according to the drug’s prescribing label. Propecia is also known by its drug name, finasteride.

Propecia is a 5-alpha-reductase inhibitor. It works by blocking the enzyme 5-alpha-reductase, which converts testosterone into dihydrotestosterone (DHT). DHT is a hormone linked to hair loss, so reducing its levels can help slow hair loss and promote regrowth.

How do I take it?
Prescribing information states that Propecia is taken by mouth as a tablet, once daily. It may be taken with or without food. Daily use for three months or more is generally needed before benefit is observed. Propecia should be taken exactly as prescribed by a healthcare provider.

Side effects
Common side effects of Propecia include decreased libido (sex drive), erectile dysfunction (trouble getting or keeping an erection), and ejaculation disorder. 

Rare but serious side effects may include allergic reactions such as rash, itching, hives, and swelling of the lips and face. Propecia causes a decrease in serum prostate-specific antigen (PSA) levels, which may affect the detection of prostate cancer. There is also an increased risk of high-grade prostate cancer associated with 5-alpha-reductase inhibitors.

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Label: Propecia — Finasteride Tablet, Film Coated — DailyMed