Finasteride for Hair Loss: Does It Work?

Published February 4th, 2021 by Chris Riley
Fact Checked by
Camille Freking
Medically Reviewed:
Gerardo Sison
Updated Date: Jun 22nd, 2022

Male pattern baldness might seem inevitable, but that doesn’t make it any less frustrating and embarrassing for many men, particularly at a young age.

The American Hair Loss Association reports that 95 percent of hair loss in men is caused by androgenic alopecia, or male pattern hair loss which is a genetic condition that causes a receding hairline and thinning hair on the crown of the head. 

Male pattern baldness occurs at a younger age than many people realize, with two thirds of all American men experiencing appreciable hair loss by the age of 35 and approximately 85 percent of men experiencing significant hair loss by the age of 50.

An estimated 25 percent of men who experience male pattern baldness begin losing their hair before the age of 21. 

With most men desperate to reverse their hair loss, a number of different treatments and medications have popped up in recent decades that promise to address the problem.

Taking finasteride for hair loss is one of the most common recommendations to help stop balding, but does it work?

What is finasteride?

Finasteride, brand name Propecia, is an FDA-approved prescription drug that is used for the treatment of enlarged prostate (benign prostatic hyperplasia) and male pattern baldness or hair loss.

Oral finasteride is sold as a tablet and topical spray and is available in both brand name and generic forms.

The medication was originally studied as a treatment for benign prostatic hyperplasia, but researchers noted that one of the side effects of the medication seemed to be a regrowth of hair and a slowing of hair loss in men suffering from male pattern baldness, especially in the vertex area of the scalp.

Since then, numerous studies have been conducted that demonstrate finasteride’s ability to treat male pattern baldness, also known as androgenetic alopecia.

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How does finasteride work?

Finasteride is a 5-alpha-reductase inhibitor; 5-alpha-reductase is an enzyme that is responsible for the conversion of testosterone into androgen dihydrotestosterone (DHT).

DHT contributes to baldness because it can cause the hair follicle to shrink and become smaller, which can eventually cause baldness; it also causes the prostate to increase in size.

Androgenetic alopecia, also known as male pattern baldness, is attributed to DHT in men who are predisposed to the condition.

Finasteride lowers the level of DHT in the scalp by up to 60 percent, which prevents the shrinking of scalp hair follicles.

Currently, lowering the levels of DHT in the scalp is the only clinically proven way to stop hair loss. 

Does finasteride work for hair loss? 

Finasteride has been clinically proven to be effective in stopping hair loss and encouraging hair regrowth.

A study conducted in 1999 found that taking 1 mg of finasteride orally each day promotes hair growth and prevents further hair loss in 48 percent of study participants in one year and up to 66 percent in two years.

After two years, 83 percent of participants receiving finasteride showed no further hair loss compared to 28 percent of those receiving the placebo. 

The medication is generally well tolerated, making it a popular choice for men suffering from male pattern baldness.

Clinical trials have also shown that it's generally safe to take topical minoxidil (brand name Rogaine) alongside finasteride to tackle both hair loss prevention and hair regrowth. 

Are there any side effects associated with finasteride?

One of the benefits of finasteride is that it is generally well tolerated when taken at the recommended dose of 1 mg per day.

However, some side effects are associated with use of the medication regardless of whether it is used to treat benign prostatic hyperplasia or male pattern baldness. Mild side effects associated with finasteride include:

  • Sexual side effects such as:
  • Skin rash
  • Breast enlargement and breast tenderness

Mild side effects resulting from the use of finasteride generally disappear over the course of a few days or a few weeks as your body adjusts to the medication.

Patients who experience these side effects in a severe form or for an extended period of time should seek medical advice from their healthcare professional to discuss alternative options or discontinuation.

Some serious side effects can potentially be life threatening. Patients experiencing any of the following side effects should contact a doctor right away and should contact 911 if their symptoms feel life threatening.

  • Swelling of your lips, tongue, throat, or face
  • Lumps or pain in your breasts
  • Depression
  • Nipple discharge

Are there any potential risks associated with the use of finasteride?

Finasteride is generally well tolerated, but it does come with several warnings for adverse effects.

Finasteride can cause severe allergic reactions associated with symptoms such as trouble breathing, hives, and swelling of the throat or tongue.

Patients experiencing any of these symptoms should call 911 or go to the nearest emergency room for treatment. 

Although finasteride is an oral medication, it can be transmitted through the skin. Women who are pregnant or are planning to become pregnant soon should not touch finasteride, as the drug can cause birth defects in women who are pregnant.

Finasteride is generally not recommended for use in women who are able to become pregnant, and it should never be used during pregnancy because of its ability to cause birth defects. Similarly, women who are breastfeeding should never use finasteride. At this time, it is unknown whether or not the medication passes through breast milk. 

Finasteride may also be dangerous for people at risk of developing high grade prostate cancer.

Finasteride can cause prostate cancer to grow faster and is also associated with the development of irregular forms of prostate cancer.

People who have prostate cancer, have had prostate cancer previously, or have a strong family history of prostate cancer should speak to their doctors about their medical history before using finasteride. 

People with liver disease should also use caution when taking finasteride, as the medication is processed in the liver.

People with liver disease may process the medication more slowly than others, which can increase the risk of experiencing side effects and can increase the severity of side effects. Your doctor may choose to lower your dose of finasteride to minimize the possibility. 

Can finasteride be used to treat hair loss in women?

Finasteride has been shown to be an effective treatment for hair loss in men, and it is typically given at a dose of 1 mg per day.

The medication does not recommend the medication for the treatment of hair loss in women, but some studies have been done examining the effectiveness of finasteride when used to treat female hair loss. 

Postmenopausal women often experience a thinning of their hair due to hormonal changes, and with relatively few treatment options on the market for women experiencing hair loss, researchers conducted a study in 2000 to determine if finasteride might be an effective treatment for women’s hair loss.

Unfortunately, the study of 137 postmenopausal women between the ages of 41 and 60 concluded that taking 1 mg per day of finasteride, the typical male dose, for 12 months neither increased hair growth or slowed the progression of hair thinning. 

While finasteride is not typically recommended for women who have not yet undergone menopause due to its ability to cause birth defects, researchers decided to conduct further studies on the treatment in order to determine if it might work for premenopausal women and postmenopausal women at different dosages. 

A more recent clinical study found that treating women with hair loss for 3 months with 2.5 mg per day resulted in at least some improvement for 95 percent of study participants.

Approximately 30 percent of women treated with the dosage showed slight improvement in hair count, while 65 percent showed significant improvement.

Few if any side effects were experienced during the study. 

An observational study examined what would happen if women took 5 mg of finasteride per day to treat hair loss.

While the dose was found to improve hair thickness and density, it also contributed to excess hair growth on other parts of the body and other side effects, such as decreased libido and breast tenderness. Overall, the 2.5 mg dose achieved similar hair regrowth results with fewer side effects.


Finasteride is an effective oral prescription medication treatment for hair loss that results from male pattern baldness in men.

Although finasteride is not officially approved for use in women, studies have shown that women who take a 2.5 mg dose of the medication can slow hair loss and regrow hair.

Finasteride is available in both brand name and generic forms of the drug and can easily be purchased at your local pharmacy with a doctor’s prescription.

Research, Studies and Sources:

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