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Dutasteride vs. Finasteride for Hair Loss

Knox Beasley, MD

Reviewed by Knox Beasley, MD

Written by Rachel Sacks

Published 09/17/2017

Updated 01/18/2024

Hair today, gone tomorrow can make any man rush to their healthcare provider for a solution to regain their once-full head of hair. But with so many treatment options out there, how’s a guy supposed to know which ones grow hair the fastest and which ones are too good to be true?

While hair loss treatments can be a bit of trial-and-error, there are well-studied, effective treatments — two of which are the medications finasteride and dutasteride. But is dutasteride better than finasteride? Or should you be using finasteride and dutasteride together? 

While finasteride and dutasteride work the same way to promote hair regrowth, there are some medical and legal differences you should know about finasteride vs dutasteride before you consider using either medication.

Keep reading for the breakdown of dutasteride vs finasteride to see which hair loss treatment wins the battle.

Dutasteride vs Finasteride: How They Work

Before we get into whether you should use finasteride or dutasteride, let’s cover some basic information about these medications — namely, how they slow down male pattern baldness.

Finasteride and dutasteride belong to a class of medications called 5-alpha reductase inhibitors, or 5-ARIs. They prevent the conversion of testosterone into a different type of androgen hormone called dihydrotestosterone, or DHT — a process that’s driven by an enzyme called 5-alpha reductase.

DHT is strongly linked to hair loss, with research showing that it’s the main hormone responsible for androgenetic alopecia, or male pattern baldness.

If you drew the genetic short stick and are predisposed to male pattern baldness, DHT can bind to androgen receptors in your scalp and cause your hair follicles to gradually stop producing new hairs. Over time, this can result in a receding hairline, thinning of your hair around the crown (the area at the top of your head) and near-total hair loss.

This is where finasteride and dutasteride come in — 5-alpha reductase inhibitors work by blocking the effects of the enzyme that converts testosterone into DHT.

Although they’re usually not a cure for baldness, these medications can slow down, stop or even reverse the negative effects that DHT can have on your hair growth cycle by blocking 5 alpha-reductase and reducing DHT levels throughout your body. 

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Comparing Finasteride vs Dutasteride

Although finasteride and dutasteride work similarly, there are a few differences between the two medications regarding effectiveness, adverse effects and legal availability.

We’ve listed these below, along with more information on how each medication works and what you can expect from each hair loss treatment, such as potential side effects.

Finasteride Was Developed First

Finasteride was initially approved by the Food and Drug Administration (FDA) to treat benign prostatic hyperplasia (BPH), which is an enlarged prostate gland. By lowering DHT levels, finasteride helps to reduce prostate enlargement.

The oral tablet version of finasteride was developed in the 1970s, patented in the 1980s and FDA-approved in 1992 for BPH under the brand name Proscar®. The drug then approved male pattern hair loss under the brand name Propecia® in 1997.

When used for hair loss, finasteride is prescribed at a lower daily dosage (1mg per day) than the stronger 5mg version used to treat BPH.

Dutasteride, on the other hand, received its FDA approval as a treatment for BPH in 2001, under the brand name Avodart®.

Only Finasteride is FDA-Approved to Treat Hair Loss

Although research shows that dutasteride is effective at treating hair loss, it hasn’t yet received approval from the FDA as a hair loss treatment.

Dutasteride is approved by the FDA, but only as a treatment for BPH. This means that it’s gone through the FDA’s rigorous testing and research process, but solely as a drug marketed with the intended purpose of prostate volume reduction.

But if only finasteride is approved to treat hair loss, why are we even talking about dutasteride for hair loss?

Dutasteride may not be approved by the FDA for this type of use, but it’s still effective at preventing male pattern baldness (we’ll talk about this effectiveness in more detail soon).

However, since the FDA has yet to approve it for this specific purpose, it can only be prescribed as an “off-label” treatment for hair loss in the United States.

Finasteride and Dutasteride Are Both Proven to Treat Hair Loss

While only finasteride is approved by the FDA as a treatment for hair loss, studies have largely shown that both finasteride and dutasteride are effective at cutting DHT production and treating male pattern hair loss.

One study from 2006 compared the effects of finasteride and dutasteride on 416 men between 21 to 45 years old who received either dutasteride, finasteride or a placebo treatment.

They noted that both finasteride and dutasteride were successful at increasing scalp hair growth over a 24-week period, and that side effects were similar among both groups.

It’s worth noting that although finasteride and dutasteride were both effective at treating hair loss and promoting hair growth, the researchers found that the men who took dutasteride had thicker hair — and a higher average hair count — after 24 weeks than the men who used finasteride. The finasteride dosage was also five times the FDA-approved amount for hair loss.

In other words, the efficacy of dutasteride for pattern hair loss may be higher than that of finasteride, at least based on this study.

A review published in the journal Clinical Interventions in Aging, which featured data from three studies comparing dutasteride and finasteride as treatments for male pattern baldness, came to a similar conclusion.

The researchers concluded that although both medications are effective at treating hair loss in men, dutasteride “seems to provide a better efficacy compared with finasteride,” with a broadly similar rate of potential side effects.

In short, while both medications work for the treatment of hair loss, there’s some evidence that dutasteride may be slightly more effective.

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Dutasteride Blocks More DHT Than Finasteride

One reason that dutasteride may be a slightly more effective treatment than finasteride is that it appears to prevent more testosterone from being converted into DHT.

A 2004 review comparing dutasteride and finasteride found that while finasteride was more selective in the types of 5-alpha reductase enzyme it blocked, dutasteride reduced DHT significantly more.

Why does dutasteride seemingly have more of an effect on DHT than finasteride? One theory is that dutasteride has a longer half-life, meaning it stays in the body longer than finasteride after it’s taken. 

Dutasteride’s half-life is approximately five weeks, meaning one dose of dutasteride can remain in the body for more than a month.

Finasteride, on the other hand, has a half-life of approximately five to six hours. This means that each dose of finasteride lasts for a significantly shorter period of time in your body than a typical dose of dutasteride.

Of course, this doesn’t mean finasteride isn’t effective at stopping hair loss in men. Several studies have found that finasteride reduces hair loss and, for many men, leads to serious improvements in hair growth.

A 2003 review of studies on men with mild to moderate hair loss who used finasteride found that many saw hair regrowth and experienced no adverse effects from the medication.

Another study carried out in Japan, which looked at the effects of finasteride over a 10-year period, also found that it was effective at treating male pattern baldness.

In this study, 99.1 percent of balding men who used finasteride over a 10-year period reported that their hair loss stopped during treatment, while 91.5 percent of the men experienced improvements in hair growth.

In general, most men with hair loss who use finasteride report that their hair loss either slows down, stops or reverses with long-term treatment.

While there is study data that suggests dutasteride may increase hair growth in men more than finasteride, this doesn’t mean that dutasteride is necessarily better to use as a hair loss treatment.

Dutasteride vs Finasteride Side Effects

So, finasteride and dutasteride both work by inhibiting the 5-alpha reductase enzyme and reducing the amount of DHT in your body. Does this mean they have similar side effects?

The most common side effects of finasteride are:

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

  • Gynecomastia (male breast tissue growth)

  • Decreased ejaculation volume

  • Sexual side effects, like reduced sexual desire

  • Testicular pain or discomfort

Finasteride may also cause or contribute to psychological effects, including an increased risk of depression.

The most common side effects of dutasteride are very similar:

  • Erectile dysfunction

  • Decrease in sex drive

  • Problems ejaculating

  • Gynecomastia

In clinical trials of Avodart, a common version of dutasteride used to treat BPH, a slightly higher percentage of men reported sexual side effects, such as erectile dysfunction, during the first six months of treatment vs. those using the placebo.

Although uncommon, 5-alpha reductase inhibitors such as finasteride and dutasteride may also cause more serious side effects. These include:

  • Swelling of the breasts and nipples

  • Lumps, pain and discomfort of the breasts

  • Discharge from the nipples

  • Difficulty breathing and/or swallowing

  • Rash, itching, hives and swelling of the face and lips

  • Peeling skin

These reactions are rare, but may be signs of a serious problem. It’s important to contact your healthcare provider as soon as possible for medical advice if you experience any of these side effects after taking either finasteride or dutasteride. 

Although finasteride may lower overall prostate cancer risk for men, some research suggests that it may be associated with an increased risk of high-grade prostate cancer in older men.

Overall, studies show that for the majority of men, finasteride is a safe medication and side effects are rare, reversible and generally not permanent. 

Likewise, research suggests that dutasteride has good long-term efficacy and long-term safety, even at the higher doses used for prostate gland volume reduction in men with BPH.

Side effects and adverse events from dutasteride are rare, often transient in nature and usually go away after you stop treatment.

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Dutasteride vs Finasteride: Final Thoughts

Hair loss can leave many men feeling dejected, and the wide world of hair loss treatments can be overwhelming. You might be left wondering which treatment you should choose — finasteride or dutasteride?

  • Finasteride and dutasteride are both 5-alpha reductase inhibitor medications that stop your body from converting testosterone into DHT, a hormone that causes male pattern hair loss.

  • While both medications work similarly, only finasteride is approved by the FDA to treat hair loss, while dutasteride is only approved to treat benign prostatic hyperplasia. Healthcare providers may prescribe dutasteride off-label for hair loss.

  • Both are effective at reducing hair loss, although some studies suggest dutasteride is more effective at blocking DHT and encouraging thicker hair growth.

  • Like many medications, side effects are possible with either finasteride or dutasteride. Both cause similar side effects, such as erectile dysfunction, reduced libido and decreased sex drive.

Since it’s the only FDA-approved option to treat hair loss out of the two, finasteride is the obvious choice if you’re looking for an effective and readily available medication to prevent your hair loss from worsening.

We offer finasteride online, along with other hair loss treatments, following a consultation with a licensed healthcare provider who will determine if a prescription is appropriate.

But finasteride isn’t your only FDA-approved hair loss treatment option. Minoxidil is a topical solution that is thought to stimulate hair growth. This medication is applied to the scalp as either a minoxidil foam or a liquid minoxidil solution.

We also offer finasteride and minoxidil in our Hair Power Pack, as well as a topical finasteride & minoxidil spray that allows you to apply both hair-loss medications directly to your scalp.

16 Sources

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  2. Ho, C.H., Sood, T., Zito, P.M. Androgenetic Alopecia. [Updated 2022 Oct 16]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK430924/
  3. Kinter, K.J., Amraei, R., Anekar, A.A. Biochemistry, Dihydrotestosterone. [Updated 2023 Jul 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Retrieved from https://www.ncbi.nlm.nih.gov/books/NBK557634/
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  8. Dutasteride. (2016, February 15). MedlinePlus. Retrieved from https://medlineplus.gov/druginfo/meds/a603001.html
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  11. Zhou, Z., Song, S., Gao, Z., Wu, J., Ma, J., & Cui, Y. (2019). The efficacy and safety of dutasteride compared with finasteride in treating men with androgenetic alopecia: a systematic review and meta-analysis. Clinical interventions in aging, 14, 399–406. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6388756/
  12. Nickel J. C. (2004). Comparison of clinical trials with finasteride and dutasteride. Reviews in urology, 6 Suppl 9(Suppl 9), S31–S39. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1472914/
  13. HIGHLIGHTS OF PRESCRIBING INFORMATION These highlights do not include all the information needed to use AVODART safely and effec. (n.d.). accessdata.fda.gov. Retrieved from https://www.accessdata.fda.gov/drugsatfda_docs/label/2020/021319s032lbl.pdf
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  15. 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 https://www.researchgate.net/publication/337105943_Long-term_10-year_efficacy_of_finasteride_in_523_Japanese_men_with_androgenetic_alopecia
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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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