Acne and Propecia
At first, researchers thought that Propecia might help with acne. This is because Propecia blocks the enzyme Type II 5α-reductase. This enzyme is responsible for converting the male hormone testosterone into dihydrotestosterone (DHT). DHT is an important cause of some acne. However, the oil glands responsible for acne have a different type of this enzyme (Type I) that is not blocked by Propecia.
Propecia has not been shown to be effective for treating acne and is not approved for this use.
It is impossible for your healthcare provider to know whether you will develop acne (or whether your acne might improve) while taking Propecia. Also, if a person does develop acne, it is difficult to know whether the symptoms are caused by other problems or Propecia itself.
However, if you develop acne while on Propecia, talk to your healthcare provider. He or she can talk to you about possible acne treatment options for your particular situation.