Finasteride sexual side effects: can they last?
Finasteride can lower sex drive and cause erection problems. The UK leaflet warns these can continue after stopping. It's called post-finasteride syndrome.
SIDEfxHUB is a patient charity. We are not health professionals, and this does not replace medical advice. Don't start, stop or change any medicine because of what you read here. Talk to your doctor first.
If you are in crisis:116 123 Samaritans (UK)988 Lifeline (US)Find a helpline
Finasteride can lower your sex drive and cause problems with erections and ejaculation. The UK patient leaflet warns that these have continued in some men after they stopped taking it, a condition patients call post-finasteride syndrome (PFS).
The NHS page says so too. Neither mentions something many men with PFS describe: a penis that has lost its feeling.
The story in 3 lines
1. In the trials, a few men on finasteride had sexual side effects, and they usually cleared up (US label).
2. The UK leaflet warns that sexual problems have continued after stopping (leaflet).
3. Nobody has measured how often (2022 criteria). Patients call it PFS.
Press: contact@sidefxhub.com
Matt took finasteride for three years and noticed nothing. Then, quite suddenly, the feeling in his genitals went. He’s turning 30 this year, and he hasn’t felt an orgasm since he was 24.
At first, Matt and his dermatologist agreed finasteride probably wasn’t the cause. Stopping it didn’t bring the feeling back, he says, and new symptoms began in the weeks after. In 2024 the UK medicines regulator, the MHRA, said finasteride’s lasting sexual side effects were “not well known by prescribers and patients”.
How common are finasteride’s sexual side effects?
In the trials of the 1 mg hair-loss tablet, about 4 in 100 men had a sexual side effect in the first year, against 2 in 100 on a dummy tablet. A lower sex drive came top. The problems cleared up in the men who stopped, says the US label, and in most who kept going.
Those trials may have missed some. A 2015 review of the hair-loss trials found that none of them reported side effects properly, and that sexual ones were probably undercounted.
Worry may play a part too. In a 2007 trial of men taking finasteride for an enlarged prostate, those who were told it might affect their sex life reported far more sexual side effects than those who weren’t.
Can finasteride side effects last after you stop?
Yes, in some men. The UK leaflet lists “persistent difficulty having an erection after discontinuation of treatment”, along with a lasting drop in sex drive and ejaculation problems. How often that happens is marked “frequency unknown”.
Finasteride leaves the body within days. So when problems last for years, the drug has long gone.
In almost half of the UK reports of sexual problems on finasteride, the MHRA says, the outcome was recorded as “not recovered”. For some men it has lasted years after stopping. Nobody knows yet who will be affected, or whether it will ease.
In 2012 the US regulator, the FDA, said it was “not aware of any additional controlled clinical studies” into the cause of these problems, or how long they last.
Does finasteride cause genital numbness?
Many men with PFS say it did, though the UK leaflet and the US label don’t mention it. In one Italian study of men with lasting symptoms, almost 9 in 10 said their penis had lost sensation. That was more common than severe erection problems, and it’s how Matt’s problems began.
The doctors and researchers behind the 2022 diagnostic criteria list less feeling in the genitals and in orgasm among the common signs of PFS. In a small Milan study, tests on the nerve that carries feeling from the genitals came back abnormal in men with PFS and severe erection problems.
Doctors don’t all agree that PFS is a condition of its own. Dr Maria Uloko, a US urologist, told colleagues in 2023 that it’s controversial in urology. She also urged them to take their patients’ concerns seriously.
What can I do?
Finasteride helps many men keep their hair. If you have side effects, that’s a decision for you and your prescriber. The MHRA makes one exception: if you get low mood or suicidal thoughts on the 1 mg tablet, it says to stop straight away and contact your doctor.
If your doctor doesn’t believe you. Many people say it took time to be taken seriously. Bring the leaflet line: “persistent difficulty having an erection after discontinuation of treatment”. You can report it without a doctor agreeing.
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?
Does finasteride shrink the penis? No label mentions it, but some men with lasting symptoms say theirs has got smaller. In a small US study of men with PFS, some reported a loss of length. Nobody measured them before they took finasteride, so it isn’t known how often this happens, or why.
Can a short course cause lasting problems? Some men say it did. Sumair used topical finasteride four times and went on to have numbness and erection problems. In one US records study, though, young men who took it for longer were more likely to have erection problems that lasted.
Is PFS only sexual? No. The 2022 criteria say finasteride can also affect cognition and mood, with or without sexual problems. Our page on post-finasteride syndrome lists the other symptoms, and our article on finasteride’s serious side effects covers mood.
Matt stopped taking finasteride, and the feeling didn’t come back. If your story sounds like his, a report puts it on the record.
If you’re struggling with your mental health, you can call Samaritans free on 116 123 in the UK, at any hour. In the US, call or text 988.
Sources
Every source below was checked on 10 October 2026.
- Propecia (finasteride 1 mg), US prescribing information and patient information, DailyMed. Prescribing information revised August 2022, patient information November 2023. The trial figures are from the three year-long 1 mg trials: 36 of 945 men on finasteride (3.8%) and 20 of 934 on placebo (2.1%) reported a drug-related sexual side effect.
- Propecia 1 mg tablets, patient information leaflet, revised May 2026, section 4, and summary of product characteristics, text revised 29 June 2026, section 5.2 (half-life about 5 to 6 hours in men aged 18 to 60). Electronic Medicines Compendium.
- NHS, Side effects of finasteride, last reviewed 2 August 2023.
- MHRA, Finasteride: reminder of the risk of psychiatric side effects and of sexual side effects (which may persist after discontinuation of treatment), Drug Safety Update, 29 April 2024. Of 426 Yellow Card reports of sexual dysfunction with finasteride 1 mg and 5 mg up to 5 April 2024, almost half were recorded as “not recovered” or “not resolved”.
- US Food and Drug Administration, Questions and answers: finasteride label changes, 11 April 2012 (archived).
- 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. On how often it happens: “The incidence of these conditions is unknown.” On how often function returns: “has never been properly investigated”.
- Belknap SM, Aslam I, Kiguradze T and colleagues. Adverse event reporting in clinical trials of finasteride for androgenic alopecia: a meta-analysis. JAMA Dermatol 2015;151(6):600-6. 34 trials; none had adequate safety reporting.
- Mondaini N, Gontero P, Giubilei G and colleagues. Finasteride 5 mg and sexual side effects: how many of these are related to a nocebo phenomenon? J Sex Med 2007;4(6):1708-12. 107 men with an enlarged prostate, all on 5 mg; 43.6% of those told about sexual side effects reported one, against 15.3% of those not told. No placebo group.
- Chiriacò G, Cauci S, Mazzon G, Trombetta C. An observational retrospective evaluation of 79 young men with long-term adverse effects after use of finasteride against androgenetic alopecia. Andrology 2016;4(2):245-50. 87% reported loss of penis sensitivity. Men recruited at a Trieste clinic and through a website, with no comparison group.
- Melcangi RC, Santi D, Spezzano R and colleagues. Neuroactive steroid levels and psychiatric and andrological features in post-finasteride patients. J Steroid Biochem Mol Biol 2017;171:229-35. 16 men, tested only after finasteride.
- Khera M, Than JK, Anaissie J and colleagues. Penile vascular abnormalities in young men with persistent side effects after finasteride use for the treatment of androgenic alopecia. Transl Androl Urol 2020;9(3):1201-9. 9 of 25 men reported loss of penile length.
- 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; among 4,284 men aged 16 to 42 on the hair-loss dose, those who took it for more than 205 days had a higher risk of erectile dysfunction lasting at least 90 days after stopping. Funded by the US National Institutes of Health, with a gift from the Post-Finasteride Syndrome Foundation.
- Uloko M. Common drug-induced sexual dysfunction in men, Perspectives in Urology, 10 March 2023. Grand Rounds in Urology.
- Videos: Moral Medicine, Matt’s film, 6 April 2026; Grand Rounds in Urology, Dr Maria Uloko, 20 July 2023.
- Photo: Kristoferb, Propecia box and tablet, public domain, via Wikimedia Commons, served from this site.
This information does not replace medical advice. Talk to your doctor before you make any decision about your treatment.
610+ people have joined the community.
Join them, then report your side effects.
Free. Sign up takes 2 minutes.