Post-finasteride syndrome (PFS): what do regulators acknowledge, what do the studies show, and what does no one know yet?

Post-finasteride syndrome (PFS) is the collective name for complaints that remain even after stopping finasteride. Finasteride reduces DHT (dihydrotestosterone) production by inhibiting the 5-alpha reductase enzyme, and has been approved for treating male pattern hair loss since 1997.711 Per Pereira and Coelho's 2020 review, in recent years reports have emerged of side effects that persisted for at least three months after stopping, and the name post-finasteride syndrome was coined for this. The persistent complaints can be sexual, psychological and neurological (neuropsychiatric), and physical.7

In 2022, Healy and colleagues proposed diagnostic criteria for it. Per these, a common shared feature is reduced genital and orgasm sensation, decreased sexual desire and erectile dysfunction; emotional numbing and worsened cognition can also occur. The criteria were compiled from two public case collections and a panel of experts, and the authors write that they'll likely need revising in light of new data.9

What you can take from this: the name PFS describes a symptom pattern, and studies have so far neither confirmed nor disproven whether it's a distinct condition.7

Regulatory documents acknowledge that sexual dysfunction can persist after stopping finasteride, and describe its frequency as unknown. The FDA-approved Propecia label lists this among post-marketing experience: "sexual dysfunction that continued after discontinuation of treatment, including erectile dysfunction, libido disorders, ejaculation disorders, and orgasm disorders". It also states that these are voluntarily reported from a population of unknown size, so their frequency and causal relationship to the medication can't always be reliably estimated.1

The British Propecia summary of product characteristics (the regulator-approved professional description of the medication) states the same: sexual dysfunction, meaning decreased sexual desire, erectile dysfunction and ejaculation disorders, can persist after stopping treatment.2 The patient information leaflet places these in the "frequency not known" category.3 "Not known" means a rate can't be calculated from existing data: it doesn't say it's rare, nor that it's common.5

None of these documents use the name post-finasteride syndrome; they describe the symptom. What you can take from this: the regulator can be cited for the possibility of a persistent symptom, not for a frequency figure.

Mood-related side effects have been strengthened in the regulatory text in recent years, and in 2025 became a mandatory, uniform measure across the European Union. On the American (FDA) Propecia label, depression was already listed among post-marketing experience before 2012. The April 2012 revision added sexual dysfunction that continues after stopping treatment, and the July 2022 revision added suicidal ideation and behaviour.1 Per Al Saffar and colleagues' 2023 urology review, this was accompanied by patient reports, and a PFS patient organisation petitioned for the medication's withdrawal or a stronger warning. The authors state that most current evidence, mainly from the dermatology literature, suggests that depressive symptoms are more common in those taking a 5-alpha reductase inhibitor; in the absence of comprehensive randomised trials, though, they say the causal relationship between finasteride and suicidal ideation isn't established.11

In the European Union, the French medicines regulator (ANSM) initiated the review on 13 September 2024, and notice of the procedure's start was published in October.124 The European Medicines Agency's (EMA) safety committee, the PRAC, confirmed in May 2025 that suicidal ideation is a side effect of the 1 mg and 5 mg finasteride tablet. Per the assessment report, the PRAC confirmed a causal link between oral finasteride and suicidal ideation, and for the 1 mg tablet, still judged the benefit-risk balance to remain favourable together with the new measures.12 This is a development that came after the Al Saffar review. The coordination group of member states (CMDh) adopted the measures on 19 June 2025, and the European Commission made a decision binding on all member states on 22 August 2025.45

The CMDh adopted its position by majority vote.4 Belgium's and France's representatives filed a dissenting opinion: in their view, for the 1 mg tablet used for hair loss, the benefit-risk balance is negative, because for a benign, cosmetic condition the expected benefit doesn't outweigh the risk of psychiatric and sexual side effects, and in some patients the side effects can persist for years after stopping. They also argued that the proposed measures, including the revised leaflet, the patient card, and a letter to healthcare professionals, don't adequately prevent the risk of suicidal ideation. Per their argument, in France, reports of serious psychiatric and sexual side effects have kept coming in despite years of measures by the French regulator.13 The majority held that the balance remained favourable with the new measures.412 The 1 mg tablet's label now also warns that sexual dysfunction, a known side effect, may contribute to mood change, and a patient card is added to the box.5 The finasteride products' leaflet already warned about mood change, depression and suicidal ideation before this decision.5

What you can take from this: per the 2025 EU decision, a patient card is added to the 1 mg tablet's box, warning about mood-related and sexual symptoms and what to do.

The 325 cases are reports, and the number of reports doesn't tell you how many of those taking finasteride this happens to. The EMA's review found 325 relevant cases of suicidal ideation in EudraVigilance, the European database for suspected side-effect reports: 313 with finasteride, 13 with dutasteride, and one with both. These were judged probably or possibly linked to treatment, and most cases occurred in patients treated for hair loss.4

The regulator assessed this alongside estimated exposure: roughly 270 million patient-years for finasteride, and roughly 82 million for dutasteride. A patient-year is one person's worth of a year's use.4 The two numbers could be divided by each other, but the result wouldn't be a frequency: reporting is voluntary, comes from a population of unknown size, and a single report alone doesn't prove that the medication caused the complaint.1 Based on a combined assessment of the reported cases and the literature, the PRAC nonetheless confirmed the causal link for oral finasteride; what's not known is the frequency, because that can't be estimated from existing data.125

These 325 cases concern suicidal ideation. For the persistent sexual complaint, the EMA's assessment report cites an American analysis (Ali and colleagues, 2015): in the FDA's side-effect database (FAERS), of 4,910 reports between 1998 and 2013 about men aged 18 to 45 taking 1 mg, 577 concerned persistent sexual dysfunction.12 Its denominator is the number of reports, not the number of people taking the medication, so a frequency can't be stated from this either. What you can take from this: the 325 doesn't establish rarity or frequency either way, and the regulator itself can't calculate a rate from it.

PFS is addressed by case series, follow-ups and regulatory reports; I found no controlled study that measured the frequency of the persistent complaint among those taking finasteride. Michael Irwig's 2012 follow-up reassessed 54 men whose sexual complaint had persisted for at least three months after stopping finasteride. Per the inclusion criteria, they were otherwise healthy young men who had no sexual dysfunction, illness, or psychiatric condition before finasteride, and weren't taking any oral prescription medication.8

The follow-up assessment took place 9 to 16 months later, 14 months on average, with an 81 percent participation rate. In 96 percent of participants the complaint was still present, and per a questionnaire measuring sexual function, the ASEX scale, 89 percent met the definition of sexual dysfunction. Neither the duration of use nor how long the complaint had already lasted was linked to how the questionnaire score changed.8 I couldn't access the study's full text, and I'm working from its abstract.

The 96 percent is easy to misread. The denominator is 54 men who already had a persistent complaint at enrolment, so the figure shows that for them, the complaint was still there a year later. It doesn't show what percentage of those taking finasteride develop a persistent complaint, and there was no control group either.8 What you can take from this: in this study, once the complaint had already lasted months, it typically persisted long-term; it doesn't reveal who goes on to develop one.

The mechanism isn't established. Irwig writes that in several rat experiments, 5-alpha reductase inhibitors changed erectile function unfavourably, but whether these changes are permanent is still being researched.8 Per Pereira and Coelho, if the syndrome does genuinely exist, it appears to occur in susceptible individuals, even after a low dose and short use, and symptoms can persist for a long time.7 Who is susceptible, and why, isn't known, and research doesn't know either.

In one study, information about the side effect increased the reported sexual side effect even during use; this study doesn't address the complaint after stopping. The nocebo effect is a side effect that doesn't stem from the drug's own action.10 In 2007, Mondaini and colleagues gave 120 men treated for enlarged prostate 5 mg finasteride daily for a year, without telling them the medication's name. One group was told the medication could cause a sexual side effect, the other wasn't.10

Of the 107 men who completed the study, 43.6 percent in the informed group (55 people) and 15.3 percent in the uninformed group (52 people) reported at least one sexual side effect.10 The study measured the complaint with a 5 mg dose, in men with prostate disease, and during use, so it doesn't translate one-to-one to the 1 mg used for hair or to the period after stopping. I couldn't access its full text, and I'm working from its abstract.

What follows from this is that information alone can increase the reported complaint. I found no measurement of how much of the persistent complaints is nocebo, and studies have neither confirmed nor disproven PFS either.7 What you can take from this: the existence of the nocebo effect doesn't prove that the persistent complaint is imagined, nor that the medication caused it.

There's a measured rate for the sexual side effect during use; there isn't for the persistent version. In the placebo-controlled trials of the 1 mg tablet used for hair loss, in the first year, 3.8 percent of those taking finasteride and 2.1 percent of those on placebo reported a medication-related sexual side effect. Over the following four years, this fell to 0.6 percent in those taking finasteride, and in the first year roughly 1 percent in both groups stopped treatment because of it.2 The full list and frequencies are in the article on finasteride's side effects. The frequency of the persistent, post-stopping complaint isn't known.3

Per Pereira and Coelho, based on current data, using a 5-alpha reductase inhibitor should be weighed carefully and individually in those who previously had depression, sexual dysfunction, or infertility.7 Al Saffar and colleagues recommend a mental health screening when starting finasteride; this is one expert group's recommendation.11

Per the EMA, anyone who notices a mood change while taking 1 mg finasteride should stop taking it and see a doctor as soon as possible. For sexual dysfunction, see a doctor, who will consider stopping if needed.56 Ask your doctor this before you start: does my history of depression or sexual complaints change how this should be weighed for me, and who should I tell if I notice a change while taking it?

You can see a doctor about a persistent symptom, and the suspected side effect can also be reported to the medicines regulator. Per Propecia's patient information leaflet, the patient can report the side effect directly to the regulator, and this gathers more information about the medication's safety.3 In its 2025 review, the EMA also drew on the European database of such reports, EudraVigilance.4 I wrote about stopping finasteride, and what happens to hair and DHT afterwards, in a separate article.

What you can take from this: the regulator works from these reports when it re-assesses a medication's safety, as it did with finasteride in 2025.

Microneedling is a mechanical stimulus with no hormonal effect, so it can be used alongside medications that act on DHT. Dermastamp is a fixed 1 mm, at-home device: the needle stimulates the area around the follicle, and its mechanism doesn't touch DHT. This is inferred from the mechanism, not measured. You don't skip oral finasteride or dutasteride on the day of stamping. With scalp-applied products, the day of stamping is a pause, and the exact timing differs by product: the timing of actives. For anyone who'd rather not touch their hormones, this is a route that stays open, with one limitation: in the study measuring the combination, both groups also received minoxidil, and the study used a 1.5 mm clinical roller, not our fixed 1 mm device; there's less data for standalone use. What it can do, what it can't, and who it's not for: I've written it all on its page.

See Dermastamp