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Finasteride for Hair Loss: Side Effects, Dosage & More

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by Geoffrey C. Whittaker

Published 09/14/2017

Updated 04/01/2024

If you’ve been looking into Propecia or its generic finasteride, for hair loss, you probably have many questions. Good news! As you might expect from the headline, we’re here to answer a lot of them at once. The first thing to know? Finasteride is a popular and safe medication for hair loss that is effective for many men with few adverse effects.

Oral finasteride does two things: it prevents further hair loss due to androgenic alopecia by protecting follicles and promotes hair growth on the scalp. It’s one of the few treatments for male pattern baldness on the market today that have been proven effective.

How it works, how much to take and what side effects to expect — that’s what we’ll dive into below.

The truth about finasteride for hair loss

You may have heard of finasteride, a generic medication also sold as Propecia® or Proscar®. Propecia is a brand name that’s used to market finasteride sold by the pharmaceutical company Merck & Co. Finasteride, whether a generic or brand name, is used to treat androgenetic alopecia, or male pattern baldness.

Originally, finasteride was FDA-approved as medication for benign prostatic hyperplasia, or BPH — a form of non-cancerous prostate enlargement — under the brand name Proscar.

Several years later, it was approved for hair loss and sold as Propecia. Today, both versions of finasteride — the higher-dose version used to treat an enlarged prostate gland and the lower-dose version used for hair loss — are available as generics and under various brand names.

Finasteride comes in tablet form and is designed for daily use, according to an article published in the book StatPearls. It’s typically prescribed at 1mg per day as a treatment for hair loss.

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Finasteride tablets belong to a class of medications called 5 alpha-reductase inhibitors, or 5-ARIs. It works by inhibiting the action of the 5 alpha-reductase enzyme, which is involved in converting testosterone into the hormone dihydrotestosterone (DHT).

DHT plays a central role in male pattern baldness. If you’re genetically prone to hair loss, DHT can bind to receptors in your hair follicles and cause them to miniaturize, resulting in a gradual loss of hair around your hairline, crown or across your scalp.

Our guide to DHT and male hair loss discusses the effects of DHT on your hair follicles in more detail.

By inhibiting the 5 alpha-reductase enzyme, finasteride significantly reduces the amount of DHT in your bloodstream, shielding your hair follicles from DHT-related damage.

Research shows that using finasteride as recommended lowers serum DHT levels (the amount of DHT in your bloodstream) by more than 70 percent.

This reduction in DHT can slow, or even stop, your hair loss. Many men even notice a significant degree of hair regrowth in areas of the scalp affected by male pattern baldness after starting treatment with finasteride.

So, does finasteride produce results? For most men, absolutely.

Research shows that finasteride works, often very well. In long-term, placebo-controlled clinical trials published in the Journal of Investigative Dermatology Symposium Proceedings, 90 percent of men with hair loss who used finasteride either maintained their hair or saw improvements in hair growth.

In comparison, 75 percent of men who used a non-therapeutic placebo experienced worsening hair loss over the same period.

In one study published in the Journal of the American Academy of Dermatology that involved two one-year clinical trials, researchers found that finasteride produced a more than 15 percent increase in hair count at the vertex scalp (the crown or area at the top of the scalp) in men with male pattern baldness.

Another study from Japan, which covered ten years of finasteride use, found that more than 90 percent of men with androgenetic hair loss who use finasteride experience improvements.

In short, finasteride works, with most men experiencing improvements in their hair growth and density with treatment.

It’s common and normal to experience a little bit of hair loss daily. Most guys shed 50 and 100 hairs per day, even if they aren’t affected by male androgenetic alopecia, or male pattern baldness.

If you’re one of the many men with male pattern baldness, however, the hair loss you see is due to the effects of a hormone — an androgen — killing off their hair follicles.

Currently, finasteride is FDA-approved to treat male pattern baldness, the most common type of hair loss in men.

However, male pattern hair loss isn’t the only type of hair loss. Other types of hair loss that can affect you include:

  • Telogen effluvium. This is a temporary form of hair loss caused by severe stress, infections, surgery, illnesses that cause fever, nutritional deficiencies, hormonal changes and certain types of medication.

  • Alopecia areata. This is a form of autoimmune hair loss, in which your hair can fall out in small, round patches. Experts aren’t entirely sure what triggers this type of hair loss, although it may be related to stress, infections and certain medications.

  • Tinea capitis. Also referred to as scalp ringworm, this type of fungal infection can cause patchy hair loss.

Since DHT doesn’t cause these types of hair loss, finasteride isn’t effective at slowing them down, stopping them or reversing their effects.

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Like almost all medications, finasteride can cause side effects. Most side effects of finasteride for hair loss are generally mild, although some may impact your quality of life.

Potential side effects of finasteride include:

  • Decreased libido

  • Inability to get or maintain an erection (erectile dysfunction)

  • Pain or discomfort that affects the testicles

  • Ejaculation disorders or problems, such as decreased ejaculatory volume

  • Changes in mood or depression

Sexual side effects — such as erectile dysfunction, difficulty ejaculating and a weaker sex drive — can sound alarming, and they can happen. But there are also a variety of things you can do to counteract this effect.

If you would like more information, we have a more in-depth article that goes over the link between ED and hair loss.

Although it’s uncommon in the low-strength version of finasteride used to treat hair loss, some men who use Proscar also report side effects such as breast tenderness and skin rashes. If you experience breast tenderness or nipple discharge, report these side effects to a healthcare provider, as they may be a sign of breast cancer.

Although the risk is low, finasteride is also associated with an increased risk of getting a more severe form of prostate cancer called high-grade prostate cancer.

In men over 55 years old, the risk of developing high-grade prostate cancer increases from 1.0 percent to 1.8 percent with the use of 5mg finasteride.

It’s important to note that this incidence of this severe side effect is from a far higher dosage of finasteride (5 mg tablet vs. 1 mg) than the dose that’s used to treat hair loss.

We also have some more good news about side effects — per the FDA label for finasteride, no significant drug interactions are associated with this medication.

Be sure to seek medical advice and tell a healthcare professional about all your current medications, supplements and health risks before using finasteride.

Are Finasteride Side Effects Serious?

It’s important to look at these side effects in context before you write off finasteride as a hair loss treatment.

Even in studies of Proscar, the high-strength 5mg version of finasteride, only a small percentage of men report these side effects.

For example, in clinical studies of finasteride for BPH, just over eight percent of men reported an effect on their erections, with 6.4 percent and 3.7 percent of men reporting decreases in libido and a reduced ejaculation volume, respectively.

Other finasteride side effects, such as breast tenderness and rash, were reported by less than one percent of men who used finasteride in clinical trials.

In clinical trials involving the 1mg per day dose used to treat hair loss, sexual dysfunction from finasteride was far less common, with just 1.8 percent of men reporting a weakened libido and 1.3 percent reporting erectile dysfunction.

It’s worth noting that many men who took a non-therapeutic placebo also reported these side effects.

How Often Do Side Effects of Finasteride Last?

As with many other medications, some side effects of finasteride may fade away or become less severe with long-term use.

Although this is uncommon, a small percentage of men may continue to experience adverse events after discontinuing the use of finasteride.

Our guide to the side effects of finasteride looks at this data in more detail and provides some additional information on what you should expect while using finasteride for hair loss.

Finasteride is typically sold in two dosages. As a treatment for male pattern baldness, it’s used at a dosage of 1 mg per day.

This is the dose of finasteride you’ll find in most generic versions of finasteride for hair loss, as well as the brand-name medication Propecia.

As a treatment for benign prostatic hyperplasia (BPH), finasteride is used at a dosage of 5 mg per day.

This dose can be found in generic forms of finasteride and the brand-name medication Proscar.

People who are breastfeeding, pregnant women, people with liver disease and those taking medications like dutasteride should consult their healthcare provider before taking finasteride.

If you experience an allergic reaction, stop taking finasteride and contact a healthcare provider.

Finasteride is effective, but there’s one catch: it doesn’t work overnight. To get consistent results from finasteride, you’ll need to have a long-term outlook and take it consistently for several months.

On average, it takes three to four months to see new hair or any other improvements from finasteride.

This isn’t because the medication isn’t working. In fact, finasteride starts reducing DHT levels as soon as your body absorbs it.

But your hair takes time to grow, meaning you’ll need to be patient before the effects of finasteride become visible.

Data from clinical trials shows that most guys experience improvements from finasteride after a year of consistent use.

In short, once you start using finasteride, you can expect to see some change in your hair after a few months.

After one year of continuous use, you should be able to see more “final” results from finasteride.

For most men, finasteride is an effective option for treating and preventing hair loss from male pattern baldness.

However, it’s not the only hair loss treatment that’s available. Other affordable and effective hair loss treatment options include:

  • Minoxidil. Minoxidil, a topical medication, helps improve blood flow to the scalp and stimulate hair growth. Research shows that minoxidil is particularly effective when it’s used at the same time as finasteride. We offer minoxidil solution and minoxidil foam online. You can also purchase finasteride and minoxidil together in our Hair Power Pack.

  • Hair loss prevention shampoo. Many shampoos, including those that contain active ingredients such as saw palmetto and ketoconazole, are formulated to prevent excess hair shedding and promote optimal hair growth. Our Hair Thickening Shampoo uses saw palmetto to target DHT at the scalp level and boost volume and moisture.

Is finasteride hair growth the most efficient way to treat hair loss? It’s hard to say. But we know that there are countless men out there who will try just about anything they can to stop male pattern baldness instead of waiting the year for finasteride to work.

Unfortunately, many of the hair loss treatments currently on the market either don’t work or are effective but very expensive. These include:

  • Laser combs and other products. Often referred to as low-level laser therapy (LLLT), these products use laser light to stimulate the hair follicles. Research is mixed on their effectiveness, and many of these devices cost hundreds or thousands of dollars.

  • Hair oils. Several essential oils are marketed as treatments for pattern hair loss. While some have been shown to have mild benefits in small studies, none are as effective as FDA-approved hair loss treatments such as finasteride and minoxidil.

  • Corticosteroids. These medications are used to reduce inflammation, which can cause hair loss in certain situations. While they may be useful for some non-hormonal forms of hair loss, there’s no evidence that they prevent or slow down pattern hair loss. In addition, topical corticosteroids may be prescribed for certain inflammatory scalp conditions, but they’re not used for male pattern baldness.

  • Hair transplant surgery. Although hair transplant surgery is effective, it’s an expensive option. The cost of a hair transplant can vary from a few thousand to tens of thousands of dollars, depending on the extent of your hair loss and the number of grafts required.

Out of all the hair loss remedies, only two offer a good combination of affordability and efficacy — oral finasteride and topical minoxidil.

Hair loss treatments, delivered

Finasteride is popular for a reason — more than any other hair loss medication, it’s effective at slowing down, stopping and even reversing the effects of male pattern baldness.

Losing your hair is never easy, but fortunately, hair loss isn’t something you have to live with. If you’re one of the tens of millions of men in the United States affected by this condition, taking early action can help you to enjoy a fuller, thicker head of hair throughout your life.

We offer finasteride and other proven, science-based hair loss medications online, following a consultation with a healthcare provider who will determine if a prescription is appropriate.

13 Sources

  1. Bistas, et al. (2021, March 27). Finasteride. StatPearls. Retrieved from
  2. Ho, et al, P.M. (2021, May 5). Androgenetic Alopecia. StatPearls. Retrieved from
  3. Kaufman, K.D., et al. (1998, October). Finasteride in the treatment of men with androgenetic alopecia. Finasteride Male Pattern Hair Loss Study Group. Journal of the American Academy of Dermatology. 39 (4 Pt 1), 578-89. Retrieved from
  4. 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
  5. Do You Have Hair Loss or Hair Shedding? (n.d.). Retrieved from
  6. Hughes, E.C. & Saleh, D. (2021, June 8). Telogen Effluvium. StatPearls. Retrieved from
  7. Lepe, K. & Zito, P.M. (2021, January 7). Alopecia Areata. StatPearls. Retrieved from
  8. Finasteride. (2018, January 15). Retrieved from
  9. PROPECIA® (finasteride) tablets for oral use. (2012, April). Retrieved from
  10. FDA Drug Safety Communication: 5-alpha reductase inhibitors (5-ARIs) may increase the risk of a more serious form of prostate cancer. (2011, June 9). Retrieved from
  11. Badri, et al. (2021, April 13). Minoxidil. StatPearls. Retrieved from
  12. Hu, R., et al. (2015, September-October). ​​Combined treatment with oral finasteride and topical minoxidil in male androgenetic alopecia: a randomized and comparative study in Chinese patients. Dermatologic Therapy. 28 (5), 303-308. Retrieved from
  13. Shapiro, J., & Kaufman, K. D. (2015, December 16). Use of finasteride in the treatment of men with androgenetic alopecia (male pattern hair loss). Journal of Investigative Dermatology Symposium Proceedings. Retrieved March 31, 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. 





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