Dutasteride for Hair Loss: Results and Side Effects
Dutasteride is off-label for hair loss in the US. Trial results vs finasteride, side-effect rates from the prescribing information, and the half-life.
By Juan Montes
Updated October 19, 2026 · 11 min read
PrescribedRX is a telehealth platform; prescriptions are written by licensed clinicians and filled by licensed partner pharmacies.
Short answer: Dutasteride is a prescription pill related to finasteride for hair loss. In the US its prescribing information (Avodart) covers only an enlarged prostate, so using it for hair loss here is off-label, although it is approved for male pattern hair loss in South Korea and Japan. In a GSK-sponsored 24-week trial of 917 men, the authors reported that 0.5 mg of dutasteride increased hair count more than 1 mg of finasteride, with similar side effects across groups (JAAD, 2014). The Avodart prescribing information lists impotence, decreased libido and ejaculation disorders among side effects, and says men should not donate blood until at least 6 months after their last dose (Avodart prescribing information).
PrescribedRX does not offer dutasteride. This guide explains what the prescribing information and the trials say so you can have an informed talk with a clinician.
What is dutasteride, and is it approved for hair loss?
Dutasteride belongs to a group of drugs called 5-alpha reductase inhibitors. These block the enzyme that turns testosterone into dihydrotestosterone (DHT). Dutasteride blocks both type 1 and type 2 forms of the enzyme. Finasteride blocks only type 2 (Gubelin Harcha et al., 2014).
In the US, the Avodart (dutasteride 0.5 mg) prescribing information covers “the treatment of symptomatic benign prostatic hyperplasia (BPH) in men with an enlarged prostate.” The US prescribing information does not mention hair loss (Avodart prescribing information).
Other countries have gone further. Japan’s drug regulator, the PMDA, reviewed dutasteride for male androgenetic alopecia in 2015 under the brand name Zagallo, at 0.1 mg a day with an option to increase to 0.5 mg (PMDA review report). A 2022 Korean study notes that dutasteride was approved for hair loss in South Korea in 2009 (Choi et al., 2022).
Off-label means a licensed prescriber can choose to use a prescription drug for a condition its prescribing information does not cover.
Does dutasteride work for hair loss? What the trials report
Here are the main studies of oral dutasteride in men with pattern hair loss. GSK (GlaxoSmithKline) was involved in two of them, and we note that where it applies.
| Study | Men | Length | Comparison | Main result | Funding |
|---|---|---|---|---|---|
| Gubelin Harcha 2014 (randomized) | 917, aged 20 to 50 | 24 weeks | Dutasteride 0.02, 0.1 or 0.5 mg vs finasteride 1 mg vs placebo | Authors reported 0.5 mg exceeded finasteride on hair count, hair width and frontal photos; side effects similar | GSK-sponsored; 3 of 9 authors were GSK employees |
| Eun 2010 (randomized) | 153 Korean men, 18 to 49 | 6 months | Dutasteride 0.5 mg vs placebo | +12.2 vs +4.7 hairs per cm2 | Not stated in abstract |
| Zhou 2019 (meta-analysis) | 576 men, 3 trials | 24 weeks | Dutasteride vs finasteride | Authors reported a greater gain in total hair count with dutasteride; similar sexual side effects | Authors report no conflicts |
| Choi 2022 (chart review) | 600 Korean men | Long-term, observational | Dutasteride vs finasteride in clinics | Authors reported greater improvement in hair loss grade with dutasteride | GSK-funded |
The biggest trial. Gubelin Harcha and colleagues randomized 917 men. Hair count and width rose with dose. At 24 weeks, the authors reported that 0.5 mg of dutasteride outperformed 1 mg of finasteride on hair count (P = .003), hair width (P = .004) and expert ratings of frontal photos (P = .002). The number and severity of side effects were similar across groups. The trial was GSK-sponsored, and three of its nine authors worked for GlaxoSmithKline (JAAD, 2014).
A placebo-controlled trial. In 153 Korean men, hair counts rose by 12.2 per square centimeter with dutasteride 0.5 mg versus 4.7 with placebo over 6 months (P = .0319), with no major difference in side effects (Eun et al., 2010).
Pooled data. A meta-analysis of 3 trials and 576 men found a mean difference of 28.57 hairs in total hair count in favor of dutasteride (95% CI 18.75 to 38.39). Rates of sexual side effects were similar to finasteride (Zhou et al., 2019). The analysis covered only 24 weeks of treatment.
Real-world data. A Korean chart review of 600 men found greater improvement in hair loss grade with dutasteride. Among men on the recommended doses, side effects were reported in 7.6% of dutasteride users and 10.5% of finasteride users. This was not a randomized trial, and GSK funded it (Choi et al., 2022).
Limits of the evidence. The randomized trials ran for 6 months or less, and longer data come from chart reviews. The trials did not test what happens when men stop. For finasteride, the Propecia prescribing information says stopping “leads to reversal of effect within 12 months” (Propecia prescribing information), and it is reasonable to ask your clinician whether the same applies to dutasteride.
What are the side effects of dutasteride?
The most detailed side-effect numbers on this page come from the US Avodart prescribing information. They come from BPH trials in older men with enlarged prostates taking 0.5 mg daily, not from a hair-loss population (Avodart prescribing information).
Sexual side effects
The table shows the share of men reporting each side effect during each period of the 2-year BPH trials, dutasteride versus placebo.
| Side effect | Months 0 to 6 | Months 7 to 12 | Months 13 to 18 | Months 19 to 24 |
|---|---|---|---|---|
| Impotence | 4.7% vs 1.7% | 1.4% vs 1.5% | 1.0% vs 0.5% | 0.8% vs 0.9% |
| Decreased libido | 3.0% vs 1.4% | 0.7% vs 0.6% | 0.3% vs 0.2% | 0.3% vs 0.1% |
| Ejaculation disorders | 1.4% vs 0.5% | 0.5% vs 0.3% | 0.5% vs 0.1% | 0.1% vs 0.0% |
| Breast disorders | 0.5% vs 0.2% | 0.8% vs 0.3% | 1.1% vs 0.3% | 0.6% vs 0.1% |
Source: Avodart (dutasteride 0.5 mg) US prescribing information, BPH trials. Not a hair-loss population.
In the prescribing information table, sexual side effects were most common in the first 6 months, and by months 19 to 24 the rates were close to placebo. The hair-loss trials above reported side-effect rates similar to finasteride.
Breast tenderness or enlargement
“Breast disorders” in the prescribing information table include breast tenderness and enlargement. Rates were 0.5% to 1.1% with dutasteride versus 0.1% to 0.3% with placebo. The prescribing information also lists male breast cancer among reports received after approval. Talk to a licensed provider about any breast changes.
Prostate cancer and PSA tests
Dutasteride lowers PSA, a blood marker used to screen for prostate cancer, by about 50%. The prescribing information advises that after 3 months or more, a PSA result should be doubled when comparing it with men who are not taking the drug. The prescribing information says any confirmed rise from the lowest PSA on treatment should be evaluated (Avodart prescribing information).
In the REDUCE trial, high-grade prostate cancer (Gleason score 8 to 10) was found in 1.0% of men on dutasteride versus 0.5% on placebo (Avodart prescribing information). The practical point: talk to any clinician who orders a PSA test about dutasteride use. That includes the $69 hormone panel, which includes PSA, used for testosterone care.
Mood changes
The Avodart prescribing information lists “depressed mood” among reports received after the drug went on sale (Avodart prescribing information). These reports do not show how often it happens. Talk to a licensed provider about any mood changes. If you have thoughts of harming yourself, call or text 988 to reach the 988 Suicide and Crisis Lifeline.
Other reports after approval
The prescribing information also lists allergic reactions (including rash, itching, hives, swelling and serious skin reactions) and testicular pain and swelling among reports received after approval (Avodart prescribing information).
How long do sexual side effects last?
In the prescribing information data, most of the extra sexual side effects showed up in the first 6 months and became less common over time. But the prescribing information also says these sexual side effects “may persist after treatment discontinuation” and that “the role of dutasteride in this persistence is unknown” (Avodart prescribing information). It does not say how often that happens. Talk to a clinician if side effects persist.
Pregnancy and handling capsules
The prescribing information says Avodart “should not be used by women or children.” Capsules “should not be handled by women who are pregnant or may be pregnant,” because dutasteride can be absorbed through the skin, with a potential risk to a male fetus. The prescribing information says that if a pregnant woman touches a leaking capsule, she should wash the area right away with soap and water (Avodart prescribing information).
How long does dutasteride stay in your system?
The prescribing information gives a half-life of about 5 weeks at steady state, and blood levels stay detectable (above 0.1 ng/mL) for up to 4 to 6 months after stopping (Avodart prescribing information). Finasteride’s half-life is about 5 to 6 hours in men aged 18 to 60 (Propecia prescribing information).
Can you donate blood while taking dutasteride?
No. The prescribing information says men taking dutasteride “should not donate blood until at least 6 months have passed following their last dose.” The goal is to keep the drug from reaching a pregnant woman who receives a transfusion (Avodart prescribing information).
Topical dutasteride: does it avoid the side effects?
There is no brand-name topical dutasteride in the US. Topical versions and injected versions (mesotherapy, small injections into the scalp) are compounded.
The evidence is limited. A 2023 concise review of dutasteride mesotherapy was published in the European Journal of Dermatology (Rodríguez-Cuadrado et al., 2023). None of the studies cited here measured how much of a topical or scalp-injected dose reaches the rest of the body, so they do not show whether these forms avoid the side effects reported with the pill.
How does dutasteride compare with finasteride?
The Propecia (finasteride 1 mg) prescribing information covers male pattern hair loss in men (Propecia prescribing information). The US Avodart prescribing information does not cover hair loss. In the 24-week trials above, the authors reported greater hair counts with dutasteride 0.5 mg than with finasteride and similar side-effect rates. The prescribing information gives dutasteride a half-life of about 5 weeks versus about 5 to 6 hours for finasteride.
| Dutasteride | Finasteride | |
|---|---|---|
| Enzymes blocked | Type 1 and type 2 | Type 2 |
| US prescribing information covers hair loss | No (BPH only, as Avodart) | Yes (Propecia 1 mg) |
| Half-life | About 5 weeks | About 5 to 6 hours (ages 18 to 60) |
| Blood donation | Wait at least 6 months after last dose (Avodart prescribing information) | Ask your clinician |
| Where approved for hair loss | South Korea, Japan (not the US) | US (Propecia) |
For more, read our comparison of minoxidil vs finasteride and our overview of hair loss treatments for men.
When should you call a doctor?
Talk to a licensed provider about any of the following. Each comes from the Avodart prescribing information sections cited above.
- Signs of an allergic reaction, such as swelling or a serious skin reaction (listed among the prescribing information’s post-approval reports).
- Breast tenderness, enlargement or a lump (the prescribing information lists breast disorders and reports of male breast cancer).
- Low mood (the prescribing information lists depressed mood). For thoughts of self-harm, the 988 Suicide and Crisis Lifeline answers calls and texts at 988.
- Sexual side effects that persist (the prescribing information says they may persist after stopping).
- Testicular pain or swelling (listed among the prescribing information’s post-approval reports).
- A partner who is or may be pregnant has handled a broken or leaking capsule (the prescribing information says pregnant women should not handle capsules).
- An upcoming PSA test or prostate biopsy (the prescribing information says dutasteride lowers PSA by about 50%).
Our hair loss treatment safety information covers the treatments PrescribedRX offers.
How does PrescribedRX approach hair loss?
PrescribedRX does not offer dutasteride. Our hair loss treatment is Hair We Grow, our finasteride and minoxidil capsule. It combines both medicines in one daily capsule. Hair We Grow is compounded, and it does not contain dutasteride. Compounded medications are prepared by licensed pharmacies and are not FDA-approved.
You complete an online intake, and a licensed provider reviews it, typically within 48 hours, and decides whether it is appropriate for you. Your provider sets the dose. Plans are self-pay, priority shipping is included, and availability varies by state.
Prices as shown on prescribedrx.com in October 2026 (see what every PrescribedRX treatment costs):
| Plan | Price | Type |
|---|---|---|
| Hair We Grow, monthly | Monthly plan $90 a month | Compounded |
| Hair We Grow, 3 months | 3 month plan $220 · $73/mo · Billed every 3 months. Cancel anytime. | Compounded |
Frequently asked questions
Is dutasteride used for hair loss in the US?
Only off-label. In the US, the Avodart (dutasteride) prescribing information covers only symptoms of an enlarged prostate (BPH). Off-label means a prescriber can choose it for a condition its prescribing information does not cover. It is approved for male pattern hair loss in South Korea and Japan.
Do dutasteride side effects go away?
In the Avodart prescribing information data, impotence, low libido and ejaculation problems were most common in the first 6 months and close to placebo by months 19 to 24. The prescribing information also says sexual side effects may persist after stopping. Talk to a licensed provider about any that last.
Is topical dutasteride safer than oral?
The evidence is limited. Topical and injected dutasteride are compounded, and none of the studies cited here measured how much of a topical dose reaches the rest of the body.
How long does dutasteride stay in your system?
The Avodart prescribing information gives a half-life of about 5 weeks at steady state, and says the drug can still be detected in blood for up to 4 to 6 months after the last dose.
Can I donate blood on dutasteride?
Not while taking it. The Avodart prescribing information says men should wait at least 6 months after their last dose before donating blood. The prescribing information says this is to keep the drug from reaching a pregnant woman through a transfusion, because of a potential risk to a male fetus.
Questions about hair loss treatment? Talk to a licensed provider
A licensed provider can review your history and the options available in your state, and decides whether a treatment is appropriate for you. Explore prescription hair loss treatment online.
Hair We Grow combines finasteride and minoxidil in one daily capsule (compounded): 3 month plan $220 · $73/mo · Billed every 3 months. Cancel anytime. A licensed provider decides whether it is appropriate for you.
Related reading: dutasteride vs finasteride: what the trials compared
Sources
- DailyMed, National Library of Medicine. AVODART (dutasteride) capsules prescribing information (rev. 10/2023). dailymed.nlm.nih.gov. Accessed Oct 2026.
- DailyMed, National Library of Medicine. PROPECIA (finasteride) tablets prescribing information. dailymed.nlm.nih.gov. Accessed Oct 2026.
- Gubelin Harcha W, et al. A randomized, active- and placebo-controlled study of the efficacy and safety of different doses of dutasteride versus placebo and finasteride in the treatment of male subjects with androgenetic alopecia. J Am Acad Dermatol. 2014;70(3):489-498. PubMed. Accessed Oct 2026.
- Eun HC, et al. Efficacy, safety, and tolerability of dutasteride 0.5 mg once daily in male patients with male pattern hair loss: a randomized, double-blind, placebo-controlled, phase III study. J Am Acad Dermatol. 2010;63(2):252-258. PubMed. Accessed Oct 2026.
- Zhou Z, et al. The efficacy and safety of dutasteride compared with finasteride in treating men with androgenetic alopecia: a systematic review and meta-analysis. Clin Interv Aging. 2019;14:399-406. PMC. Accessed Oct 2026.
- Choi GS, et al. Long-term effectiveness and safety of dutasteride versus finasteride in patients with male androgenic alopecia in South Korea: a multicentre chart review study. Ann Dermatol. 2022;34(5):349-359. PMC. Accessed Oct 2026.
- Pharmaceuticals and Medical Devices Agency (Japan). Review Report: Zagallo (dutasteride) for androgenetic alopecia (2015). pmda.go.jp. Accessed Oct 2026.
- Rodríguez-Cuadrado FJ, Pinto-Pulido EL, Fernández-Parrado M. Mesotherapy with dutasteride for androgenetic alopecia: a concise review of the literature. Eur J Dermatol. 2023;33(1):72. PubMed. Accessed Oct 2026.
- 988 Suicide and Crisis Lifeline. 988lifeline.org. Accessed Oct 2026.
This article is for general information. It is not medical advice and it is not a recommendation for any particular treatment. Whether a treatment is appropriate for you is a decision for a licensed clinician who has reviewed your health history and current medications.
About the author
Juan MontesJuan Montes writes and reviews PrescribedRX's clinical content, covering testosterone replacement therapy, men's sexual health, weight management and hair loss. He trained as a Professional Nurse at the Colombian Red Cross in Cali, Colombia, and has worked in healthcare since 2011, roughly six of those years in direct emergency and critical care nursing. He served as Head Nurse in Emergency…
More from Juan →This article is for information only and is not medical advice. Treatment is prescribed solely at the discretion of a licensed provider following a clinical evaluation.
