PFS diagnostic criteria: what counts as PFS?

Still having problems months after stopping finasteride? Post-finasteride syndrome (PFS) is diagnosed from your history, not a scan or a blood test. The criteria proposed in 2022 ask for past use of a drug like finasteride and sexual problems that can last after stopping, for three months or more.

The UK Propecia leaflet already lists a “persistent decrease in sex drive after discontinuation of treatment”. The criteria give that experience a shape a doctor can check.

So what exactly do they ask for, and what has to be ruled out first?

What are the diagnostic criteria for PFS?

Two things must be true. You took a 5-alpha reductase inhibitor, and sexual problems have lasted after you stopped.

The 2022 criteria name finasteride, dutasteride and saw palmetto as 5-alpha reductase inhibitors. They then list what usually fits the picture:

• Less desire: a lasting drop in sex drive, or losing it completely.
• Erection problems that don’t go away after stopping.
• Less feeling: reduced genital sensation, and orgasms that feel muted.
• Time: the problem is still there three months or more after the last tablet.

Sexual problems on finasteride that clear up after stopping are not PFS, the paper says.

These are proposed criteria. An expert panel agreed them by working through drafts, starting from cases reported to a drug-safety website. Nobody has tested them in a large clinical study yet.

Which symptoms does PFS include beyond sex?

The criteria list problems with cognition, depression and suicidal thoughts as finasteride effects that “can occur independently of any sexual difficulties”. So a person can struggle with memory, focus or mood after finasteride and still not tick the sexual boxes.

The paper also names features that may come from finasteride but don’t count towards a diagnosis. These are breast tissue growth in men (gynecomastia) and changes in the amount and quality of semen.

The UK leaflet takes mood seriously too. It says that if your mood changes, you should stop taking Propecia and contact your doctor.

If you’re having thoughts of suicide, call Samaritans free on 116 123, day or night.

Robb Dixon, who works for SIDEfxHUB, has PFS. Watch him describe living with it, in his own words, on national TV.

Play video: Pharmacists warn against buying prescription drugs online

What has to be ruled out, and is there a test?

A doctor should check that nothing else explains your symptoms. The criteria list four things that should be true:

• No similar problems before. Your sexual problems didn’t match this picture before you took the drug.
• No other health condition that could account for them.
• No current medicine or substance use that could account for them.
• No other past medicine that could explain them. Some, such as SSRI antidepressants and isotretinoin, can leave similar lasting problems.

This is where tests come in. Blood tests and an examination look for other causes. A normal result doesn’t rule PFS out, and no test proves it. Researchers have found differences in some people with PFS, but none is a diagnostic test.

The 2022 paper mentions changes in neuroactive steroid levels, changes in how the 5-alpha reductase gene is switched on in spinal fluid and shifts in gut bacteria. It also notes some evidence of penile curvature. For all of these, it says it’s unclear whether they were there before treatment.

So your own record matters.

How can I prepare for my GP appointment?

These medicines help many people. If you have side effects, that’s a decision for you and your prescriber. Follow what the leaflet says: it tells you to stop and see your doctor if your mood changes.

Bring a short record:

• The medicine: “Finasteride 1 mg from March 2021, last tablet June 2024.”
• What changed: “Touch feels numb”, “no morning erections”, “I can’t concentrate”.
• When it started: while taking it, or after stopping.
• How it was before: “No problems before 2021.”

Many people say it took time to be taken seriously. Bring the leaflet line. 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?

Can women get PFS? The criteria were written from cases in men. Women do take finasteride, and our page on finasteride for women covers what is known. Describe your symptoms to your doctor in the same way.

Does dutasteride count? Yes. The criteria name dutasteride alongside finasteride and saw palmetto. The UK reporting term covers both drugs, so use the same words in a Yellow Card report.

How long must symptoms last? The criteria say three months or more after stopping. You don’t need to wait that long to see your GP or to report it.

Our PFS page explains the condition in full.

Sources

1. 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. Proposed criteria agreed by an expert panel through successive drafts, based on RxISK.org case series; not validated in a clinical study. Section 5, necessary criteria: “Prior treatment with a 5 alpha-reductase inhibitor” and “Enduring sexual dysfunction after stopping treatment”. Additional criteria include “The problem is present for ≥3 months after stopping treatment”; “Sexual dysfunction that happens on finasteride but clears after treatment stops is not PFS”; cognitive impairment, depression and suicidality “can occur independently of any sexual difficulties”.
2. Organon Pharma (UK) Limited. Propecia 1 mg patient information leaflet, electronic Medicines Compendium, revised May 2026. Section 4, frequency unknown: “persistent decrease in sex drive after discontinuation of treatment”. Section 2: if mood changes, “stop taking Propecia and contact your doctor”.
3. 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, 2024. UK.
4. GOV.UK. Report a problem with a medicine or medical device.
5. Good Morning Britain, ITV, Pharmacists warn against buying prescription drugs online, 11 February 2026.

Sources checked on 22 October 2026. AI-assisted writing and review, not clinical review.