Dealing with hair loss or thinning?

Chat with our Care Team

Start now

Propecia: Uses, Side Effects and Dosage

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by Steph Coelho

Published 08/09/2021

Updated 04/26/2024

If you’re starting to lose your hair and want to stop it from getting worse, your healthcare provider may suggest using Propecia® — either on its own or with a topical treatment like minoxidil. What is Propecia, though?

Propecia is a research-backed, FDA-approved prescription hair loss treatment. It contains the active ingredient finasteride and works by stopping testosterone from converting into the hormone dihydrotestosterone (DHT), which causes hair loss or a receding hairline in men.

Numerous studies show that the medication can slow down, stop and even reverse the effects of male pattern baldness.

Read on to learn more about Propecia for men, including how it works as a treatment for pattern hair loss. You’ll also find answers to questions about generic Propecia, a rundown of common side effects, how to access the medication, how to use it and more.

What is Propecia? How Propecia Works and How to Use It

Propecia is a prescription medication that treats androgenetic alopecia (the clinical term for male pattern baldness). Currently, Propecia is only available in tablet form. Each tablet contains 1 milligram (mg) of finasteride.

What is Propecia used for? The FDA (U.S. Food and Drug Administration) approved Propecia in 1997. Before that, healthcare providers prescribed the active ingredient finasteride to treat benign prostatic hyperplasia (BPH or enlarged prostate). 

A happy side effect? The medication also helped with androgenetic hair loss (aka male pattern hair loss or baldness). So now finasteride is used for this purpose as well.

Finasteride is available in 1-milligram and 5-milligram tablets. But the typical Propecia dosage for male pattern hair loss in men is 1 milligram daily. 

If you miss a dose, take it as soon as you remember on the same day as the missed dose. But don’t take a double dose if you forgot to take your tablet yesterday. In that case, just take your next scheduled dose.

Buy finasteride

more hair... there's a pill for that

Propecia’s active ingredient finasteride is part of a class of medications known as 5-alpha reductase inhibitors (or 5ARIs). As mentioned, it prevents your body from converting testosterone into the more potent androgenic hormone DHT.

How does this help with male pattern baldness? Let’s first dig into why this type of hair loss occurs in the first place. 

You don’t get pattern hair loss from wearing a hat that’s too tight, washing your hair too often or using too many styling products. Male pattern baldness happens thanks to a combination of genetic factors and the effects of DHT.

Your body produces DHT by converting a small percentage of its freely circulating testosterone — via an enzyme called 5 alpha-reductase. 

If you’re genetically predisposed to male pattern baldness, the DHT created from this process can bind to receptors in your scalp and gradually cause your hair follicles to shrink and stop producing new hairs.

Not everyone is equally sensitive to the effects of DHT. This is why some guys go bald in their 20s or 30s, while others maintain a full head of hair well into older adulthood.

How does finasteride fit into this? As a 5-alpha reductase inhibitor, it prevents your body from converting testosterone into DHT.

This lowers the amount of DHT that can bind to receptors in your scalp and protects your hair follicles from DHT-related damage.

Learn more about DHT and its effects on your hair follicles in our full guide to DHT and male pattern baldness.

Propecia — or, more specifically, its active ingredient, finasteride — has been the focus of research for decades. Several studies have found that it can slow down, stop and even reverse the effects of male pattern baldness. 

More recent studies have looked at the effects of finasteride on hair growth and male pattern baldness over an even longer period.

In a 2019 study published in the journal Clinical Research and Trials, a team of researchers in Japan examined the effects of finasteride in men who’d been using the medication for 10 years.

Over 99 percent of participants showed no worsening of hair loss over the entire decade of using finasteride. Even more impressively, 91.5 percent showed improvements in hair growth.

The researchers concluded finasteride showed “high efficacy and safety” as a treatment for male pattern hair loss.

Will you join thousands of happy customers?

4.5 average rating

Before/after images shared by customers who have purchased varying products, including prescription based products. Prescription products require an online consultation with a healthcare provider who will determine if a prescription is appropriate. These customers’ results have not been independently verified. Individual results will vary. Customers were given free product.

The finasteride in Propecia starts blocking DHT right away, but it can take several months to produce any noticeable changes in your hair.

Most people start to see results from Propecia after three to four months of daily use. As the medication starts to work, you may notice:

  • Your hair loss slows down, with fewer stray hairs visible on your pillowcase or in the shower drain

  • Improvements in your hair’s thickness and density, especially around the hairline or crown (the area at the top of your head)

Though Propecia is effective for most guys, it won’t completely stop your hair from falling out.

Your hair goes through a natural multi-phase hair growth cycle, and it’s common and normal to shed some hair even if you’re taking Propecia for hair loss. 

Make sure to take finasteride every day, even if you don’t notice any change in your hair during the first few months of treatment.

Propecia is an oral medication, so as long as you don’t mind swallowing pills, it’s pretty easy to use. The tablets are typically taken once a day, with or without food. As with any medication, it’s usually best to take it around the same time each day.

That said, you’ll want to follow your healthcare provider’s instructions for using this medication to make sure you’re taking it as prescribed.

Yes. Propecia was protected by a patent through the 1990s and 2000s, but like many established medications, that patent has since expired. The point is, finasteride, its active ingredient, is now available in generic form.

Generic finasteride is available in the same 1-milligram tablet dosage as brand-name Propecia. It’s equally effective at treating hair loss, making it an option worth considering if your budget is a concern.

You can get generic finasteride online, following a consultation with a licensed healthcare professional who’ll determine if a prescription is appropriate. 

Learn more in our blog on Propecia versus finasteride.

If you’ve searched online for information about Propecia hair loss medication, you may have seen references to a similar medication called Proscar®. 

Proscar is a medication for benign prostatic hyperplasia. It contains the same active ingredient as Propecia but at a higher dosage (each tablet of Proscar has 5 milligrams of finasteride versus 1 milligram for each Propecia tablet).

Your healthcare provider will likely prescribe Proscar or its generic equivalent if you have an enlarged prostate. Proscar isn’t typically used as a treatment for male pattern baldness.

Millions of men in the United States and around the world use Propecia to treat pattern hair loss, and most don’t experience significant issues. 

However, like all medications, Propecia can potentially cause side effects. 

The most common side effects of Propecia include sexual issues like:

  • Erectile dysfunction (ED)

  • Ejaculation disorder (a decreased amount of semen, or ejaculate)

  • Changes in sex drive

According to the FDA’s documentation for Propecia, these common side effects were reported by 1.2 to 1.8 percent of men who used the medication in clinical trials.

Although uncommon, other adverse effects have been reported with Proscar (the prostate enlargement medication). This includes male breast enlargement (gynecomastia) and breast tenderness or pain, which could create a male breast cancer risk.

Finasteride has also been linked to testicular pain, depression and infertility.

It’s important to keep in mind that these issues affect only a tiny percentage of people who use Propecia, Proscar or generic finasteride. 

In rare cases, Propecia can cause allergic reactions. If you experience any of the following symptoms, seek medical care as soon as possible:

  • Skin rash, itching or hives

  • Swelling on the lips or face

  • Difficulty breathing or swallowing

  • Breast changes, such as growth, pain, lumps or nipple discharge

Propecia and other medications containing finasteride might cause finasteride drug interactions when taken with certain other medications. 

Be sure to let your healthcare provider know about all medications you currently take or have recently taken before using Propecia for hair regrowth.

Another safety note: Propecia is only approved for use in men. Research has found that finasteride can contribute to birth defects when taken during pregnancy. 

Pregnant women shouldn’t take Propecia or other medications that contain finasteride — or touch broken or crushed Propecia tablets.

Propecia is only available with a valid prescription. This means you’ll need to talk to a healthcare professional to buy and use it — you can’t get it over the counter.

If you’ve noticed early signs of male pattern baldness and want to use Propecia prescription medication to prevent further hair loss, it’s best to talk to your healthcare provider.

You can buy generic finasteride online from Hims, following a virtual consultation with a licensed healthcare professional.

Hair loss treatments, delivered

Now that you have an idea of what Propecia is and what it’s used for, you might be wondering if it’s right for you.

Here’s what to keep in mind:

  • Propecia — which contains finasteride — is an effective medication for male pattern baldness that can slow, stop or even reverse hair loss.

  • Consider using finasteride with the topical hair loss medication minoxidil (which comes as a foam or liquid solution) and other science-based hair loss treatments.

  • You can also use a two-in-one product, like our topical finasteride & minoxidil spray.

  • For optimal results in your quest for hair regrowth, it’s best to connect with a healthcare professional to learn more about your individual hair needs and get medical advice on effective hair loss treatment options.

Still need help weighing your options? Check out our guide to Propecia cost for pricing and insight into insurance coverage.

7 Sources

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references.

  1. Propecia® (finasteride). (2010, December). FDA. Retrieved from
  2. Propecia® Highlights of Prescribing Information. (2012, April). FDA. Retrieved from
  3. Ho, C.H., et al. (2021, May 5). Androgenetic Alopecia. StatPearls. Retrieved from
  4. Zito, P.M., Bistas, K.G. & Syed, K. (2021, March 27). Finasteride. StatPearls. Retrieved from
  5. Yanagisawa, M., et al. (2019, January). Long-term (10-year) efficacy of finasteride in 523 Japanese men with androgenetic alopecia. Clinical Research and Trials. 5, 1-5. Retrieved from
  6. Finasteride. (2018, January 15). Retrieved from
  7. National Cancer Institute at the National Institutes of Health. (2014, February 19). NIH study confirms risk factors for male breast cancer. National Cancer Institute at the National Institutes of Health. Retrieved May 12, 2022, from
Editorial Standards

Hims & Hers has strict sourcing guidelines to ensure our content is accurate and current. We rely on peer-reviewed studies, academic research institutions, and medical associations. We strive to use primary sources and refrain from using tertiary references. See a mistake? Let us know at [email protected]!

This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment. Learn more about our editorial standards here.

Knox Beasley, MD

Dr. Knox Beasley is a board certified dermatologist specializing in hair loss. He completed his undergraduate studies at the United States Military Academy at West Point, NY, and subsequently attended medical school at Tulane University School of Medicine in New Orleans, LA. 

Dr. Beasley first began doing telemedicine during his dermatology residency in 2013 with the military, helping to diagnose dermatologic conditions in soldiers all over the world. 

Dr. Beasley is board certified by the American Board of Dermatology, and is a Fellow of the American Academy of Dermatology.

Originally from Nashville, TN, Dr. Beasley currently lives in North Carolina and enjoys spending time outdoors (with sunscreen of course) with his wife and two children in his spare time. 





Read more