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Finasteride for Male Hair Loss


Generic Name Brand Name
finasteride Propecia

Finasteride is a pill that is taken once a day.

How It Works

Finasteride lowers the level of androgens, a class of hormone that affects hair loss.

Why It Is Used

Finasteride was originally used to treat enlarged prostate glands (benign prostatic hyperplasia). In a much lower dose, it is now also used to treat inherited hair loss in men (androgenetic alopecia), the most common cause of hair loss.

Finasteride is not effective in postmenopausal women.1 It is not approved for women by the U.S. Food and Drug Administration (FDA). Women and children should not use finasteride.

How Well It Works

Finasteride is recognized as a successful therapy for inherited hair loss for men. Research reports that it slows hair loss on the scalp and helps regrow hair.2 But bald spots may not be completely covered, and visible results may take from a few months to a year.

Side Effects

All medicines have side effects. But many people don't feel the side effects, or they are able to deal with them. Ask your pharmacist about the side effects of each medicine you take. Side effects are also listed in the information that comes with your medicine.

Here are some important things to think about:

  • Usually the benefits of the medicine are more important than any minor side effects.
  • Side effects may go away after you take the medicine for a while.
  • If side effects still bother you and you wonder if you should keep taking the medicine, call your doctor. He or she may be able to lower your dose or change your medicine. Do not suddenly quit taking your medicine unless your doctor tells you to.

Call911or other emergency services right away if you have:

Call your doctor if you have:

Common side effects of this medicine include:

  • Reduced sex drive.
  • Difficulty getting an erection.
  • Ejaculation problems.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

Finasteride is for men only. Women and children should not use it.

Women who are or may become pregnant should not take or handle crushed or broken tablets because finasteride can cause birth defects.

Finasteride must be taken daily. If you stop taking finasteride, any regrown hair will gradually be lost, and within 6 to 12 months your scalp will most likely appear the same as before treatment.

If you are having a prostate screening, tell your doctor you are taking finasteride because it may affect the results of your test.

Taking medicine

Medicine is one of the many tools your doctor has to treat a health problem. Taking medicine as your doctor suggests will improve your health and may prevent future problems. If you don't take your medicines properly, you may be putting your health (and perhaps your life) at risk.

There are many reasons why people have trouble taking their medicine. But in most cases, there is something you can do. For suggestions on how to work around common problems, see the topic Taking Medicines as Prescribed.


Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.


  1. Unger WP, et al. (2010). Androgenetic alopecia. In MG Lebwohl et al., eds., Treatment of Skin Disease: Comprehensive Therapeutic Strategies, 3rd ed., pp. 36–38. Edinburgh: Saunders Elsevier.

  2. Habif TP (2010). Hair diseases. In Clinical Dermatology: A Color Guide to Diagnosis and Therapy, 5th ed., pp. 913–935. Edinburgh: Mosby Elsevier.

By Healthwise Staff
Primary Medical Reviewer Adam Husney, MD - Family Medicine
Specialist Medical Reviewer E. Gregory Thompson, MD - Internal Medicine
Last Revised May 29, 2012

WebMD Medical Reference from Healthwise

Last Updated: May 29, 2012
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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