How Does Finasteride Work? Uses and Benefits

Published February 15th, 2021 by Erik Rivera
Fact Checked by
Camille Freking
Medically Reviewed:
Dr. Gerardo Sison
Updated Date: Jun 23rd, 2022

As much as everyone hates to hear it, the reality is that the vast majority of men will experience hair loss resulting from male pattern baldness at some point during their lifetime. 

According to the American Hair Loss Association, male pattern baldness is responsible for more than 95 percent of hair loss in men.

Also called androgenic alopecia, male pattern hair loss is a hereditary condition that causes thinning hair, receding hairline, and a lack of hair regrowth particularly on the crown of the head.  

Men of any age can experience male pattern baldness after hitting puberty.

An estimated one out of every four men who suffer from male pattern baldness begin experiencing appreciable hair loss before the age of 21, and about two-thirds notice significant hair loss before the age of 35.

By the age of 50, 85 percent of men are affected. No matter what time hair loss occurs, it can be very distressing, but it increases in likelihood as men age. 

Fortunately, men do not have to live with male pattern baldness and just accept losing their hair.

Finasteride is a popular prescription medication that is sold under the brand name Propecia, and it has been found to be extremely effective for the majority of men. 

If you’re looking for a way to stop hair loss in its tracks and promote hair growth, finasteride could be a viable option for you. So, how does finasteride work?

What is finasteride?

Finasteride is a prescription medication that is approved by the U.S. Food and Drug Administration (FDA) for the treatment of male pattern baldness and benign prostatic hyperplasia (BPH), or an enlarged prostate, in men. 

Many people are familiar with finasteride, which is the generic form of the brand-name drug Propecia or Proscar, but few are aware of how it actually works and how it can treat hair loss. 

The drug was originally developed as a treatment for benign prostatic hyperplasia, but during clinical trials, researchers noticed that it seemed to slow hair loss and promote hair growth in men suffering from male pattern baldness.

The effect of the drug was particularly pronounced on the crown of the head, which is where hair thinning first begins for many men. 

Since the initial studies were conducted, additional research has continued to show finasteride’s ability to treat male pattern baldness, also known as androgenetic alopecia.

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How does finasteride work?

Finasteride works by targeting the cause of male pattern baldness at the source.

Male pattern baldness has genetic origins, but the condition begins to appear in men as levels of a hormone called dihydrotestosterone (DHT) in the body begin to rise, which usually occurs as men age.

The body uses an enzyme called 5-alpha-reductase to convert testosterone into androgen DHT.

When this enzyme becomes overactive, DHT levels in the body rise.

DHT can cause hair loss by shrinking the hair follicle, which leads to shorter, thinner hair strands. DHT also causes the prostate to become enlarged, which is why finasteride can be used to treat benign prostatic hyperplasia. 

Finasteride tablets belong to a class of drugs called 5-alpha reductase inhibitors, which work by blocking the action of the enzyme that converts testosterone into DHT, 5α-reductase.

The medication has been shown to reduce the level of DHT in the scalp by up to 60 percent

Is finasteride effective?

Since finasteride’s ability to stop hair loss was first discovered by accident during a clinical trial, the medication has been repeatedly shown to be effective at reducing hair loss and promoting hair growth in men with male pattern baldness. 

In one study, 48 percent of study participants who took 1 mg of finasteride per day, the current recommended dose, saw increased hair growth after one year of treatment, while 66 percent of participants experienced hair growth over a treatment period of two years.

After two years, 83 percent of participants receiving finasteride showed no further hair loss, while only 28 percent of people receiving the placebo drug showed no further hair loss.

Although finasteride is extremely effective when used on its own, it can also be used in conjunction with topical minoxidil (brand name Rogaine) in order to boost results.

What are the benefits of using finasteride to treat hair loss?

There are many benefits of using finasteride to treat hair loss. 

Finasteride is effective for the vast majority of men suffering from hair loss when taken over a period of several years because it treats hair loss at the source of the problem, i.e. increased levels of DHT in the body.

Most men will see improvement in their hair thickness and density while using finasteride, which can help boost the confidence of many who are suffering from male pattern baldness. 

Finasteride is also well-tolerated by most men and does not cause many side effects compared to the average prescription medication.

It is effective at a relatively low dosage of mg per day, which means that even men who are older and may have difficulty processing other medications are likely to be able to process the drug.

If mild side effects are experienced, they typically last for just a few days or weeks as your body adjusts to the medication.

One significant benefit of finasteride is that the medication is easy to incorporate into your daily routine. Unlike topical solutions, which can be messy and inconvenient, using oral finasteride is as simple as taking a pill.

Finasteride is also available in a topical solution, which effectively lowers the levels of DHT in the scalp but not in the rest of the body.

Men who are not able to tolerate the oral version of finasteride might be able to use topical finasteride with no issues.

Finasteride is also very cost effective and is available for a price of one dollar per day or less from most pharmacies and may be available for less through online telehealth services.

Although a prescription is required for the use of finasteride, it can easily be obtained online through telehealth providers like Keeps, Hims, or Roman.

Are there any side effects associated with finasteride?

For the most part, most men are able to tolerate finasteride with few side effects when taken at the recommended dosage of 1 mg per day. 

Some mild side effects may be experienced when using oral finasteride for the treatment of male pattern baldness or benign prostatic hyperplasia; however, the side effects are not associated with topical finasteride. 

Mild side effects associated with finasteride include:

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

Men who experience mild side effects of finasteride usually find that their side effects go away or reduce in intensity after the first few days or weeks of taking the medication. 

When side effects are experienced for an extended period of time, are severe in intensity, or take the form of an allergic reaction, men should seek medical advice from their healthcare professional to discuss alternative options or discontinuing the medication.

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.

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


Men who are suffering from male pattern baldness are able to obtain a convenient, effective, and well-tolerated effective treatment in the form of prescription finasteride.

This oral medication has been repeatedly proven to be effective in stopping hair loss and promoting hair growth in men experiencing male pattern baldness, and it can also be used for the treatment of benign prostatic hyperplasia. 

Finasteride is not approved for use in women or pregnant women, but there are ongoing studies about the possibility that may result in the drug’s availability for women in the future.

Finasteride is not currently recommended for those with high risk of prostate cancer, as it can lower the levels of prostate-specific antigen (PSA) in the body. 

As with all prescription or over-the-counter medications, you should seek professional medical advice before starting finasteride.

Finasteride does require a prescription, but the medication is inexpensive and can be obtained at any local pharmacy with a doctor’s prescription or through an online telehealth service.

Research, Studies and Sources:

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