Finasteride blocks an enzyme called 5-alpha-reductase, which is necessary to change testosterone to another hormone that causes the prostate to grow. As a result, the size of the prostate is decreased. The effect of finasteride on the prostate lasts only as long as the medicine is taken. If it is stopped, the prostate begins to grow again.
Finasteride also is used by some balding men to stimulate hair growth. If hair growth is going to occur with the use of finasteride, it usually occurs after the medicine has been used for about 3 months and lasts only as long as the medicine continues to be used. The new hair will be lost within 1 year after finasteride treatment is stopped.
For more information on Propecia (Finasteride), click here.
This medication requires a prescription.