Frequently Asked Questions

Straight answers about male pattern hair loss (MPHL) and PROPECIA.

Is hair loss in my future?

Mild to moderate male pattern hair loss affects about 50% of men in the United States by age 50.

Hair loss is a common problem with many men. In fact, in a nationwide survey of single, balding men, the biggest appearance-related concern was hair loss. So, if you’re worried about it, you’re not alone. Hair loss can begin in your teens, 20s, or 30s, and by the time you notice it, 50% of your hair already may be gone.

What causes MPHL?

Scientists believe DHT and family history are key factors in hair loss.

What is DHT? It’s a substance in your body that can shrink the hair follicle until it no longer produces visible hair. In men with a family history of hair loss, DHT is believed to contribute to the progressive shrinking of hair follicles and a decrease in the number of visible hairs.

In short, if you have a family history of hair loss on either side of your family, you may have an increased risk for male pattern hair loss.

See how DHT shrinks hair follicles

How does PROPECIA work?

PROPECIA significantly reduces DHT, a key cause of hair loss, by blocking the formation of DHT in your scalp.

Lowering DHT appears to inhibit the further shrinking of affected hair follicles.

The good news is that PROPECIA helps regrow visible hair and reduces further hair loss. PROPECIA is, in fact, the first and only FDA-approved pill proven to treat male pattern hair loss on the vertex (top of head) and anterior mid-scalp area (middle front of head) in men. (See Figure 1.)

The effectiveness of PROPECIA was demonstrated in studies of men, aged 18 to 41, with mild to moderate hair loss at the top and middle front of the head. There is not sufficient evidence that PROPECIA works for receding hairlines at the temples.

PROPECIA is for MEN ONLY and should NOT be taken by women or children.

When should I start PROPECIA?

Five years of clinical data with PROPECIA show that the sooner you start, the better.

If you have MPHL, the sooner you get started on PROPECIA, the more hair you may have later. In fact, in the longest reported controlled study of MPHL ever conducted, men who were treated with a placebo (sugar pill) and then switched to PROPECIA 1 year later never caught up to the men who took PROPECIA for the full 5 years.

If you stop taking PROPECIA, you will likely lose any hair you have gained within 12 months of stopping treatment.

In the first year of the study, 86% (584 of 679) of the men on PROPECIA maintained hair or increased the number of visible hairs vs 42% (282 of 672) of the men on placebo.

PROPECIA is the first and only FDA-approved pill used for the treatment of male pattern hair loss on the vertex (top of head) and anterior mid-scalp area (middle front of head). There is not sufficient evidence that PROPECIA works for receding hairlines at the temples. PROPECIA is for use by MEN ONLY and should NOT be used by women or children.

In clinical studies for PROPECIA, a small number of men experienced certain sexual side effects, such as less desire for sex, difficulty in achieving an erection, or a decrease in the amount of semen. Each of these side effects occurred in less than 2% of men and went away in men who stopped taking PROPECIA because of them.

How much does PROPECIA cost?

PROPECIA is available by prescription only. Because prices vary among pharmacies, including those on the Internet, we encourage you to shop around when you fill your prescription. See a list of US-licensed online pharmacies. Ask your doctor about PROPECIA today. Also ask your doctor about PROPAK^®, a convenient 90-day supply of PROPECIA.

Is there scientific evidence that PROPECIA works?

A 5-year clinical study demonstrated the effectiveness of PROPECIA.

• 9 of 10 men who took PROPECIA had visible results (either regrowth of hair, 48% [134 of 279], or no further hair loss, 42% [117 of 279]) vs 25% (4 of 16) who took placebo (sugar pill), according to an assessment of photographs by an independent panel of dermatologists.
• 2 of 3 men who took PROPECIA regrew hair, as measured by hair count. All men in the study who were not taking PROPECIA lost hair.
• A majority of men who took PROPECIA were rated as improved by doctors—77% (210 of 271) vs 15% (2 of 13) with placebo.
• A majority of men who took PROPECIA reported that their bald spot got smaller, their hair loss slowed down, and the appearance of their hair improved.

What’s more, in the first year of the study, 86% (587 of 679) of men who took PROPECIA maintained hair or increased the number of visible hairs vs 42% (282 of 672) who took placebo.

PROPECIA is for MEN ONLY.

Further treatment is unlikely to help if the drug has not worked within 12 months. If you stop taking PROPECIA, you will likely lose the hair you have gained within 12 months of stopping treatment.

Read about a 4-year story and additional clinical studies

How effective is PROPECIA at regrowing hair?

2 of 3 men who took PROPECIA regrew hair, as measured by hair count.

Simply put, all men who took the placebo (sugar pill) lost hair by the end of the 5-year study.

On the other hand, most men (2 of 3) who took PROPECIA gained hair at the end of the 5-year study.

By the end of the study, there was an average difference of 277 hairs in a test spot (1-inch circle on top of head) between men who took PROPECIA and men who took a placebo.

Throughout the 5-year study, the difference between the 2 groups increased. The maximum increase in hair count with PROPECIA occurred in the first 2 years of the study.

See additional results of this study

In clinical studies for PROPECIA, a small number of men experienced certain sexual side effects, such as less desire for sex, difficulty in achieving an erection, or a decrease in the amount of semen. Each of these side effects occurred in less than 2% of men and went away in men who stopped taking PROPECIA because of them.

Will there be a visible difference if I stay on PROPECIA?

9 of 10 patients who took PROPECIA had visible results (maintenance or improvement), according to photographic assessments by an independent panel of dermatologists.

An expert panel of dermatologists determined that 90% (251 of 279) of men who took PROPECIA at 5 years had improvement or no visible hair loss vs 25% (4 of 16) who took placebo (sugar pill).

Further treatment is unlikely to help if the drug has not worked within 12 months.

See Before and After photos

Will I grow natural-looking hair?

A study showed that hair grew in thicker, faster, or both.

PROPECIA grows natural hair, not just “peach fuzz.”

At the end of a 4-year study, there was an increase in the weight of hair samples taken from the men who took PROPECIA compared with hair samples taken from the men who took a placebo (sugar pill).

The effectiveness of PROPECIA was demonstrated in studies of men, aged 18 to 41, with mild to moderate hair loss at the top and middle front of the head. There is not sufficient evidence that PROPECIA works for receding hairlines at the temples.

How fast can PROPECIA work, and how long should I continue taking it?

You may see less hair loss in as little as 3 months.

You will need to take PROPECIA for as long as you want to grow or maintain your hair.

If you stop taking PROPECIA, you will likely lose the hair you have gained within 12 months of stopping treatment.

See the timeline for results

If my wife and I conceive a child while I’m taking PROPECIA,
     does PROPECIA pose a risk to the child’s development? If my wife and I have
     intercourse after she is pregnant, does PROPECIA pose a risk to the baby?

Available data indicate that the level of PROPECIA in the semen of a man taking PROPECIA does not pose a risk to an unborn child. Accordingly, a man can take PROPECIA while conceiving a child with his partner, or have sexual intercourse with his partner if she is already pregnant.

PROPECIA is for the treatment of male pattern hair loss in MEN ONLY and should NOT be used by women or children.

Women who are or may potentially be pregnant must not use PROPECIA and should not handle crushed or broken tablets of PROPECIA because the active ingredient may cause abnormalities of a male baby’s sex organs. If a woman who is pregnant comes into contact with the active ingredient in PROPECIA, a doctor should be consulted. PROPECIA tablets are coated and will prevent contact with the active ingredient during normal handling, provided that the tablets are not broken or crushed.

What are the side effects of PROPECIA, and how often do they occur?

Clinical studies showed that side effects were uncommon and did not affect most men.

A small number of men had sexual side effects, with each occurring in less than 2% of men. These included less desire for sex, difficulty in achieving an erection, and a decrease in the amount of semen. These side effects went away in men who stopped taking PROPECIA because of them. In addition, these side effects decreased to 0.3% or less by the fifth year of treatment.

In 3 controlled clinical trials for PROPECIA of 12-month duration, 1.4% of patients who took PROPECIA (n=945) were discontinued due to adverse experiences that were considered to be possibly, probably, or definitely drug related. 1.6% of patients who took a sugar pill (placebo; n=934) were discontinued due to adverse experiences.

In general use, the following side effects have been reported: allergic reactions including rash, itching, hives, and swelling of the lips and face; problems with ejaculation; breast tenderness and enlargement; and testicular pain. You should promptly report to your doctor any changes in your breasts such as lumps, pain, or nipple discharge. Tell your doctor about these or any other side effects.

Is there a number that I can call to learn more about PROPECIA?

Call 1-800-830-7375, Monday through Friday, 8:30 AM to 7:00 PM (ET). A Merck customer representative will answer your questions, send you product information, and explain special offers that may be available.

Additional Information
Hear what men are saying about their hair loss and PROPECIA
See questions for you to ask your doctor

Know the facts. PROPECIA is available by prescription only, so the best thing to do is talk with your doctor.

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch, or call 1-800-FDA-1088.

Know the facts. PROPECIA is available by prescription only, so the best thing to do is talk with your doctor.