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Propecia is a prescription drug used for the treatment of male-pattern hair loss (androgenetic alopecia). It is the only oral prescription medication approved by the U.S. Food and Drug Administration for this purpose.

Last Modified: November 21, 2022
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Although baldness affects the majority of older men in the United States, the U.S. Food and Drug Administration has approved just two drug treatments, Propecia (finasteride) and Rogaine (minoxidil). Propecia and its generic versions are the only oral prescription drugs approved for treatment of male-pattern baldness. Rogaine is a topically applied, over-the-counter treatment.

Coincidentally, both treatments for hair loss were originally developed for other conditions. The active ingredient in Rogaine was initially developed to treat high blood pressure, while the active ingredient in Propecia was first used to treat symptoms of an enlarged prostate gland, or benign prostatic hyperplasia (BPH), in a product marketed as Proscar.

After receiving FDA approval in 1997, the new formulation of finasteride marketed as Propecia was introduced as a treatment for hair loss. At the time, manufacturer Merck & Co. said it had invested $450 million in research to develop the new finasteride application. Merck said this investment justified the need to charge three times the price it was getting for Proscar, the higher-dose version of finasteride used to treat enlarged prostates.

In 1988, nearly a decade before FDA approval of Propecia, Rogaine (minoxidil) was approved to treat baldness in men. It became available to women in 1991 and started being sold over the counter for men in 1998.

The dearth of approved baldness treatments is not for lack of trying. Over the years, both legitimate researchers and con artists have looked for and sold a variety of baldness products, from wax injections and blood treatments to electricity and surgery. Snake-oil baldness treatments were common in the United States until 1938, when the industry came under the regulation of the FDA.

It’s little wonder the demand for hair loss treatments is so high. Male-pattern baldness affects more than 50 million men in the United States, making them an attractive market. The hair growth industry generates about $3.6 billion in sales each year.

One sign of how baldness affects the view of men in the United States is the fact that we have had just five bald presidents: John Adams, John Quincy Adams, Martin Van Buren, James Garfield and Dwight Eisenhower. President Donald Trump’s doctor has said he takes Propecia.

In 2014, 1.2 million prescriptions of finasteride were written for hair loss and 8.2 million were written for prostate issues. In 2011, Propecia was generating $400 million in yearly revenue for its maker, Merck.

What Is Propecia?

Propecia (finasteride) is part of a class of drugs known as 5-alpha-reductase inhibitors (5-ARIs). It is approved only for use in men because it can cause ambiguous genitalia in developing male fetuses.

Drugs in the 5-ARI class include finasteride, marketed under the brand names Proscar (5 mg) and Propecia (1 mg); and dutasteride, marketed as Avodart and Jalyn (in combination with tamsulosin).

Proscar, Avodart, and Jalyn are approved to treat symptoms of an enlarged prostate gland, or benign prostatic hyperplasia (BPH). Proscar and Avodart are also approved to reduce the risk of urinary retention or the need for BPH-related surgery.

Propecia is the only 5-ARI approved to treat male-pattern hair loss. Dutasteride is not formally approved for treating hair loss, but it may be used off-label for this purpose.

Millions of Prescriptions
Approximately 5 million male patients received a prescription for a 5-ARI between 2002 and 2009.

In order to be effective, finasteride must be taken indefinitely, as discontinuation results in the return of hair loss. While patients are expected to take finasteride over an extended period, little is known about the long-term effects of drugs in this class.

How it Works

Baldness is caused when an enzyme changes testosterone into something called dihydrotestosterone (DHT). The enzyme that transforms testosterone into DHT is known as 5-α-reductase (5-α-R). DHT, in turn, affects some hair follicles that are sensitive to the enzyme, binding to the follicles and causing them to shrink and produce thinner, shorter hairs. Eventually the follicles will stop hair production entirely.

Propecia (finasteride) stops the production of DHT in the body and helps slow hair loss in about 88 percent of men who take the drug, according to the American Academy of Dermatology.

The drug’s label instructs users to take one 1 milligram tablet once daily, with or without meals.

Within 24 hours of taking a dose of Propecia, the concentration of DHT drops by 65 percent. The full effects of daily Propecia use can take three months or more to appear. Stopping treatment leads to reversal of effect within 12 months, according to the label.

Decreased Sex Drive, Depression & Other Side Effects

According to Merck, the most common side effects of using Propecia include decreased sex drive, trouble getting or keeping an erection and a decrease in the amount of semen.

The manufacturer says the following side effects have also been reported:

  • Breast tenderness and enlargement
  • Depression
  • Decrease in sex drive that continues even after patients stop taking Propecia
  • Allergic reactions such as rash, itching, hives, or swollen lips, tongue, throat and face
  • Problems with ejaculation that continue after stopping Propecia
  • Pain in the testicles
  • Infertility
  • Male breast cancer (rare)
  • Prostate cancer

According to a 2016 research review, several large studies found no increase in prostate cancer, a possible increase of aggressive cancer, and no change in survival rate in patients who took 5-alpha-reductase inhibitors. It also found no direct link between 5-alpha-reductase inhibitors and depression, although the results of several small studies led to depression being listed on the label as a side effect. Sexual effects – such as erectile dysfunction and decreased libido – were reported in 3.4 to 15.8 percent of men.

In 2022, the FDA announced a requirement to disclose suicide risk as a potential effect of anti-baldness drugs.

Other Hair Loss Treatments in Development

Medical researchers continue to explore alternative treatments for hair loss.

For example, cyclosporine, originally used for transplant patients and people with autoimmune diseases, has been found to stimulate hair growth.

On a different front, platelet-rich plasma (PRP) therapy is being investigated to treat baldness. The therapy is used to hasten healing in a variety of medical fields, including dentistry and orthopedics. In PRP therapy, a person’s own blood is placed into a centrifuge to separate the red blood cells from the plasma. The plasma, containing growth factors, is then injected back into the patient. When PRP therapy is used for hair loss treatment, the plasma is injected directly into the patient’s hair follicles.

Another team of researchers is developing a device they are describing as a flexible, wearable photostimulator that has demonstrated the ability to grow hair on mice.

In Texas, researchers are looking at a protein known as KROX20 that purportedly tells skin cells to become hair and then to produce a protein that plays an important role in pigmentation of the hair.

Researchers elsewhere are examining possible genetic treatments, as well as treatments to generate stem cells.

Buyer Beware

Experts advise patients to be wary of companies peddling treatments that are more likely to separate money from your bank account than to restore hair. Among the treatments patients should be wary of are brushes, magnets and massagers that purport to stimulate blood circulation to the hair follicles. These claims are not supported by any reliable evidence.

The same holds for a variety of herbal supplements.

Bottom line: Talk to your doctor before trying any medical treatments for hair loss.

Please seek the advice of a medical professional before making health care decisions.
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