Dutasteride side effects: can they last?

Dutasteride (Avodart) can lower sex drive and cause erection and ejaculation problems. The UK leaflet warns these may continue after you stop taking it, a condition known as post-finasteride syndrome, or PFS.

The condition is named after finasteride, an older drug that works in a similar way. The NHS website has a medicines page on finasteride but not on dutasteride, so the leaflet in your pack is where you’ll find the warning.

Matt used dutasteride on his scalp for about eight months. Near the end, sexual side effects began, and he stopped using it.

Play video: Topical Dutasteride Left Me With Persistent Sexual Side Effects | Short Patient Testimonial

They didn’t ease. He says they “have progressively gotten worse” in the five months since he stopped, and the worst is the genital numbness. “I wish I never took this medication.”

Can dutasteride side effects last after stopping?

For some men, yes. The UK leaflet names erection problems, a lower sex drive and difficulty with ejaculation as common side effects. Each one comes with the same line: “this may continue after you stop taking Avodart”.

There’s no reliable figure for how often it happens. One US study of medical records found about 1 in 70 men who took finasteride or dutasteride had erection problems that lasted at least three months after stopping. Records like these can’t prove the drugs were the cause.

For some people it has lasted years after stopping. Nobody knows yet who will be affected, or whether it will ease.

Patients call the condition post-finasteride syndrome. The official term regulators use for reports names the whole drug group instead: Post 5-alpha-reductase inhibitor syndrome. Dutasteride’s leaflet says it belongs to that group.

Mark Moyad, a US doctor, says he’s “very glad that we have this agent” for men with an enlarged prostate. He also says the loss of sex drive “could be long lasting”, while adding that this isn’t proven.

Play video: How Avodart and Proscar Affect Libido | Mark Moyad, MD, MPH & Mark Scholz, MD | PCRI

How common are dutasteride side effects?

Common, says the UK leaflet. In the trials behind the US label, about 5 in 100 men on dutasteride had erection problems in the first six months, against about 2 in 100 on a dummy pill. These were older men with an enlarged prostate, the only use dutasteride is licensed for in the UK.

Younger men take it too. A 2022 review says doctors are increasingly prescribing it off-label for hair loss, and Japan has approved it for that.

In one small trial of men taking it for hair loss, run by its maker, sexual side effects were more common than on a dummy pill. In the dutasteride group, they had all cleared by the end of the study, some while the men were still taking it.

Could it just be dutasteride still in my body?

For the first few months, it could be. Dutasteride leaves the body very slowly. Its US label says it can still be found in the blood up to 4 to 6 months after the last capsule.

Years later is a different matter. Doctors and researchers who proposed criteria for PFS in 2022 say dutasteride, like finasteride, “can trigger an enduring sexual dysfunction”.

One sign they list is a lasting drop in genital feeling. Matt describes that numbness five months after he stopped. Nobody can say yet whether his will ease.

Dutasteride after the last capsule

Last capsule

The drug starts to leaveSlowly, over months.

First months

Still in the bloodSide effects may simply carry on.

Six months

Men can give blood againThe US label's wait, so the drug isn't passed on.

Years later

The drug is long goneFor some men, the symptoms remain.

What can I do?

These medicines help many people. If you have side effects, that’s a decision for you and your prescriber.

The MHRA says to contact your doctor if you have sexual problems on dutasteride. If you develop depression or suicidal thoughts, contact them as soon as possible. The Samaritans are on 116 123, free, at any hour.

If the problems haven’t lifted since you stopped, tell your GP and give your dates: “Avodart, one capsule a day, from January 2023. Last capsule March 2024.”

Many people say it took time to be taken seriously. Bring the leaflet line. You can report it without a doctor agreeing, and our page on post-finasteride syndrome explains the symptoms.

Report it: it helps everyone

A doctor’s note helps you. A report to the medicines regulator helps everyone else: it is how patterns get noticed.

• No proof needed. A suspicion is enough, even years after stopping.
• Where: the Yellow Card scheme in the UK, MedWatch in the US.
• Use the right words. If symptoms continued after stopping, write Post 5-alpha-reductase inhibitor syndrome (MedDRA 10082430).

Our reporting guide walks you through it

What else do people ask?

Can dutasteride affect your mood? The UK leaflet lists depression as a side effect, but can’t say how often it happens. It also warns that suicidal thoughts have been reported with another medicine of the same kind, which the MHRA names as finasteride. The MHRA added this warning in 2026 as a precaution, because the data for dutasteride was very limited.

Is dutasteride on the scalp safer? Not necessarily. The UK prescribing information says dutasteride “is absorbed through the skin”, which is why women and children mustn’t touch a leaking capsule. Matt put his on his scalp, and his symptoms began while he was still using it.

How is dutasteride different from finasteride? Both lower DHT, a hormone made from testosterone, by blocking an enzyme called 5-alpha reductase. A 2022 review says dutasteride blocks both main forms of it and finasteride mainly one, so dutasteride lowers DHT further. Our summary of a review of long-term use covers other possible effects of both drugs.

Matt says he’s “scared about the future”. If your symptoms have outlasted your last capsule, report it under the term that covers dutasteride too.

Sources

Every source below was checked on 10 October 2026.

1. Avodart 0.5 mg soft capsules, patient information leaflet, Electronic Medicines Compendium (EMC 6758), last revised March 2026. Section 1: a 5-alpha reductase inhibitor, for an enlarged prostate. Section 2: mood changes and depression reported with “another medicine from the same therapeutic class (5-alpha reductase inhibitor) by mouth”. Section 4: common side effects (“up to 1 in 10 men”), each sexual one followed by “this may continue after you stop taking Avodart”.
2. Avodart 0.5 mg soft capsules, UK summary of product characteristics, revised 11 August 2026. Section 4.1: licensed for benign prostatic hyperplasia. Section 4.4: “Dutasteride is absorbed through the skin”, and mood alterations. Section 4.8: “These adverse events may persist after treatment discontinuation. The role of dutasteride in this persistence is unknown.”
3. Avodart (dutasteride), US prescribing information and patient information, revised October 2023. DailyMed, US National Library of Medicine. Section 6.1, Table 1: impotence in months 0 to 6 in 4.7% of 2,167 men on dutasteride and 1.7% of 2,158 on placebo. Its footnote covers persistence. Section 5.5: no blood donation until at least 6 months after the last dose. Section 12.1: inhibits type 1 and type 2 5-alpha reductase. Section 12.3: half-life about 5 weeks; detectable in serum for up to 4 to 6 months after stopping. Patient information: “Some of these events may continue after you stop taking AVODART.”
4. MHRA, Finasteride and dutasteride: updated safety warnings for psychiatric side effects and sexual dysfunction, Drug Safety Update volume 19, issue 10, 11 May 2026. Dutasteride “works in a similar way to finasteride”. The mood warning was added “as a precaution”, and “The data for dutasteride was very limited”. Advice to patients on sexual side effects, depression and suicidal thoughts.
5. NHS, Medicines A to Z, checked 10 October 2026: pages for finasteride and tamsulosin, none for dutasteride. Dutasteride is named on the NHS prostate enlargement treatment page.
6. Kiguradze T, Temps WH, Yarnold PR and colleagues. Persistent erectile dysfunction in men exposed to the 5α-reductase inhibitors, finasteride, or dutasteride. PeerJ 2017;5:e3020. Northwestern Medicine records: 167 of 11,909 men (1.4%) had erectile dysfunction lasting at least 90 days after stopping, median 1,348 days. Single-group design; association, not proof of cause.
7. Gupta AK, Talukder M, Williams G. Comparison of oral minoxidil, finasteride, and dutasteride for treating androgenetic alopecia. J Dermatolog Treat 2022;33(7):2946-62. Off-label use for hair loss is increasing. Approved for male hair loss in Japan and South Korea. Dutasteride inhibits type I and II, finasteride type II; “Thus, dutasteride suppresses DHT levels more than finasteride in the serum and scalp.”
8. Tsai TF, Choi GS, Kim BJ and colleagues. Prospective randomized study of sexual function in men taking dutasteride for the treatment of androgenetic alopecia. J Dermatol 2018;45(7):799-804. Sponsored by GSK. 117 men aged 23 to 50. Sexual adverse events in 16% on dutasteride and 8% on placebo over 24 weeks. Those on dutasteride all resolved, during treatment or 2 to 6 weeks after the last dose; one that began after placebo was still resolving when that man left the study. Follow-up lasted up to 24 weeks after the last dose.
9. Healy D, Bahrick A, Bak M and colleagues. Diagnostic criteria for enduring sexual dysfunction after treatment with antidepressants, finasteride and isotretinoin. Int J Risk Saf Med 2022;33(1):65-76. Section 5, post-finasteride syndrome: criteria include prior treatment with a 5-alpha reductase inhibitor and an enduring reduction in genital and orgasmic sensation, present for at least 3 months after stopping.
10. Moral Medicine, Topical Dutasteride Left Me With Persistent Sexual Side Effects, Matt, 26 August 2026, quoted from YouTube’s automatic captions. “Have progressively gotten worse” at 0:28 (“That was 5 months ago”); “The worst is the genital numbness” at 0:39; “I wish I never took this medication” at 1:06; “I’m scared about the future” at 1:09.
11. Prostate Cancer Research Institute, How Avodart and Proscar Affect Libido, Mark Moyad and Mark Scholz, 3 May 2021, quoted from YouTube’s automatic captions. Moyad from 1:24; “very glad that we have this agent” at 2:39; “perhaps it’s not proven but perhaps it could be long lasting” at 2:53.
12. MedDRA term and code: Post 5-alpha-reductase inhibitor syndrome, 10082430.
13. Images: Editor182, Avodart, public domain; melvil, Dutasteride (ZAGALLO Capsules), 2016, CC BY-SA 4.0. Both via Wikimedia Commons, served from this site.