Research & Evidence

Is this real?

It is the first question almost everyone asks. Here is what the published research, and the medicines regulators themselves, currently say — in plain language, with every source linked.

The short version

Three things we can say with confidence

  1. 01

    The symptoms show up in the body, not just on the report form

    Brain imaging and biomarker studies find measurable physical differences in affected patients — differences you can see on a scan, not only hear in a consultation.

  2. 02

    They can continue after the medication stops

    This is no longer contested. The FDA and the EMA both require the product labelling to say so.

  3. 03

    Something is changing in how genes are switched on

    A 2021 study found expression differences across thousands of genes, and animal work found distinct brain changes. Animals hold no expectations about a drug — which makes belief a poor explanation.

Why the numbers look small

For every 100 side effects, about 5 are ever reported

Reporting a side effect is voluntary, and most people never do it — often because they do not know they can. So the official totals are a floor, not a count.

~5 reported ~95 never recorded FDA estimate: 1–10% of adverse reactions are reported. Shown here at the midpoint.

So what? When you read that a condition has “only” a few thousand reports, that number is the visible tip. It is also why the registry matters — every entry moves the floor up.

Official recognition

What the regulators have already accepted

These are not campaign claims. Each one is a change the medicines regulators required of the manufacturers.

  1. 2011
    FDA · United States

    Finasteride labels must say effects may persist

    Labelling updated to state that sexual side effects “may persist after discontinuation”.

  2. 2019
    EMA · Europe

    The same requirement for antidepressants

    SSRI and SNRI labels must state that sexual dysfunction may persist after stopping — the first formal recognition of PSSD. Read the PRAC recommendation.

  3. 2021
    MedDRA · Worldwide

    PFS gets its own code

    Post-Finasteride Syndrome was added to the dictionary used to record adverse events globally — so it can finally be counted as one thing rather than scattered across separate symptoms.

On record

What has been counted so far

21,287
Finasteride reports in WHO VigiBase
153 countries, as of 2024
11,557
Finasteride reports in FDA FAERS
The US reporting system
3,764
Genes expressed differently in PFS patients
Journal of Sexual Medicine, 2021
524
Patients in the SIDEfxHUB registry
Our own data

The awareness gap

Recognition, reporting and research depend on each other. When one link is thin, the whole chain stays weak — and patients and clinicians are both left without answers.

1

A patient describes symptoms

Persistent sexual, cognitive or emotional symptoms that continue after the medication was stopped.

2

The presentation is unfamiliar

These conditions are uncommon and are not yet a routine part of medical training, so they are easily missed.

3

No adverse event report is filed

A reaction is most likely to be reported once it is recognised. Many patients are also unaware that they can report directly themselves.

4

The evidence base stays thin

Regulators act on the reports they receive. With few on record, there is little signal to act on.

5

Little new guidance reaches clinicians

Fewer safety updates and less published guidance mean awareness stays low — and the cycle begins again.

The cycle continues
In plain words

The terms you will keep running into

Adverse event report
A formal note to a medicines regulator saying “this happened to me after taking this”. Anyone can file one — you do not need a doctor to do it for you.
Pharmacovigilance
The system that collects those reports and watches for patterns. FAERS and VigiBase are two of its databases.
Gene expression
Which genes are switched on or off, and how strongly. Your genes themselves do not change — but what they are doing can.
Neurosteroids
Hormones the brain makes itself, involved in mood, sleep and sexual function. Finasteride reduces one of the enzymes that produces them.
Nocebo effect
Symptoms caused by expecting harm. It is a real phenomenon — which is exactly why the animal studies matter, since animals hold no expectations.

Help move the floor up

Joining the registry and reporting through the official channel both add to the record — and the record is what regulators and researchers act on.

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