Finasteride side effects: an honest guide before you start
Finasteride works well for many men, and it has side effects you should hear about upfront. This guide covers how it works, realistic results, what the 2025 EMA safety review found, and how to report a problem.
Most men who take finasteride don't have any problems with it, but a minority experience finasteride side effects serious enough that you should know about them before you start. The main ones are mood changes, including low mood and suicidal thoughts, and sexual problems such as a lower sex drive. If your mood changes, stop taking it and talk to a doctor. Our doctors can go through the risks, your history and your options by video, without any pressure.
Causes
Why does hair thin in the first place?
If you've noticed your hairline creeping back or your crown getting thinner, you're far from alone. Male pattern hair loss is common, and for plenty of men it starts in their twenties. It's not a medical emergency, but it can knock your confidence, and it's completely reasonable to want to do something about it.
It mostly comes down to two things: your genes and a hormone called DHT (dihydrotestosterone). If you've inherited sensitive hair follicles, DHT slowly shrinks them. Each new hair grows back a little finer and shorter than the last, until eventually the follicle stops producing visible hair at all. That's why it tends to happen gradually, at the temples, the crown, or both.
How it works
How finasteride helps
Finasteride is one of the treatments you'll hear about most. It works well for a lot of men. It also has side effects that you deserve to know about upfront, not buried in small print. So here's the straight version, from the doctors who'd be prescribing it.
Finasteride blocks the enzyme that turns testosterone into DHT. Less DHT means less pressure on your follicles, so hair loss slows down, and in many men some hair grows back.
In Ireland, the 1 mg tablet is licensed for men aged 18 to 41 with early-stage hair loss. (You may also see a 5 mg version mentioned online. That's a different medicine for an enlarged prostate, not for hair.) Finasteride tablets aren't licensed for women or for anyone under 18.
Sources: HPRA, Finasteride 1 mg film-coated tablets (SmPC and package leaflet); HPRA notice, 12 September 2025.
What to expect
Finasteride results and hair regrowth: what to expect
This is a slow treatment, and patience is part of it. You take one tablet a day, with or without food. Most men don't see much change for the first three to six months, and it's usually around the one-year mark that you can properly judge whether it's working.
It's best at holding on to what you have. Many men stop losing hair, and some get noticeable regrowth, particularly at the crown. It's less likely to rebuild a hairline that has already receded a long way.
One thing people often don't realise: it only works while you take it. If you stop, any hair you've kept or regrown will usually be lost again over the following year or so.
Source: HPRA, Finasteride 1 mg film-coated tablets (SmPC and package leaflet).
Safety
Finasteride side effects, honestly
Most men who take finasteride don't have any problems with it. But a minority do, and some of those side effects are serious enough that we want you to know about them before you make up your mind, not after.
Your mood and mental health
In 2025, the European Medicines Agency (EMA) concluded a Europe-wide safety review of finasteride and dutasteride medicines. It confirmed suicidal thoughts as a side effect of finasteride tablets; warnings about mood changes, including depression, were already in the product information. It isn't possible to say exactly how often this happens (the EMA lists the frequency as "not known"), but most of the reports came from men taking the 1 mg tablet for hair loss.
If you've ever had depression, anxiety or suicidal thoughts in the past, please tell us before you start. It doesn't automatically rule finasteride out, but it's an important part of the conversation.
Your sex life
A small number of men notice changes such as:
- a lower sex drive
- difficulty getting or keeping an erection
- changes in ejaculation, including less semen
For most men these go away once they stop the tablets. In some, though, they've continued after treatment ended (more on that below). The EMA review also found cases where these sexual side effects contributed to changes in mood. So if anything changes, please mention it to your doctor early. It's a completely normal thing to raise and you won't be the first.
Breast changes
Some men get tender or enlarged breasts. Male breast cancer has also been reported in men taking finasteride. If you notice a lump, pain, swelling or any discharge from the nipple, get it checked promptly.
Fertility
Poor sperm quality and infertility have been reported in men taking finasteride, in some cases alongside other risk factors. Improvement has been reported after stopping. If you and your partner are trying for a baby, it's worth talking it through first.
Less common effects
A few men have reported allergic reactions (rash, itching, hives, or swelling of the lips, tongue or face), testicular pain, blood in the semen, palpitations or changes in liver tests. If you ever have trouble breathing or swallowing, treat it as an emergency and get help straight away.
Sources: European Medicines Agency, finasteride and dutasteride review; HPRA notice, 12 September 2025; HPRA, Finasteride 1 mg film-coated tablets (SmPC and package leaflet).
After stopping
Post-finasteride syndrome: when symptoms last after stopping
"Post-finasteride syndrome" is a name you will see online for symptoms that carry on after someone has stopped finasteride. The Irish product information we checked does not use that name, so here is what it does say.
The package leaflet lists a lower sex drive, difficulty getting an erection and problems with ejaculation that continue after treatment has ended as reported side effects. It separately lists anxiety and suicidal thoughts as possible side effects. For all of these, the frequency is given as "not known", which means it cannot be estimated from the available data.
So we can't tell you how many men are affected. What we can say is that it has been reported, and that if you notice sexual or mood symptoms during treatment, or that carry on after you stop, the best thing to do is tell a doctor early.
Source: HPRA, Finasteride 1 mg film-coated tablets (SmPC and package leaflet).
In the box
That card in the box
Following the EMA review, finasteride 1 mg packs come with a small patient card. It sums up the risks of mood changes, including suicidal thoughts, and of sexual problems, and what to do if they happen. It's worth reading properly, along with the leaflet, and keeping somewhere you'll find it.
Sources: European Medicines Agency; HPRA notice, 12 September 2025.
Good to know
A few practical things to know
- PSA blood tests: finasteride lowers your PSA reading, a blood test used to check the prostate. If you ever have one, tell the doctor you're on finasteride so they read the result correctly.
- If your partner is pregnant: finasteride can affect the development of a baby boy. Women who are or might be pregnant shouldn't handle crushed or broken tablets. Normal, intact tablets are coated and are fine to touch.
- Giving blood: blood services have rules about some medicines, including how long to wait after stopping them. If you donate, tell the donation team you take finasteride and follow their advice.
- Topical options: the EMA review found no evidence linking finasteride skin spray to suicidal thoughts. That finding is about suicidal thoughts, not a promise that a topical product has no side effects, but topical finasteride may be worth discussing, depending on your situation.
Sources: HPRA, Finasteride 1 mg film-coated tablets; European Medicines Agency; HPRA notice, 12 September 2025.
Your decision
So, is finasteride right for you?
Overall, the EMA concluded that the benefits of finasteride still outweigh its risks. But that's a judgement about large groups of people. Whether it makes sense for you depends on your health history, how much the hair loss bothers you, and how you feel about the possible side effects. There's no wrong answer.
It's also not the only option. Topical minoxidil, topical finasteride, light therapy and hair transplants all have their place, and some men simply decide they'd rather not treat it at all. That's a perfectly valid choice too.
Minoxidil and finasteride are different medicines. Minoxidil is applied to the scalp, and its Irish product information says the way it stimulates hair growth is not fully understood. Finasteride tablets work by lowering DHT. Minoxidil also has its own cautions: the Irish leaflet says not to use it if you have high blood pressure, and its product information says it should not be used with other medicines on the scalp. Whether one, the other or both make sense for you is something a doctor can weigh up after going through your history.
Sources: European Medicines Agency; HPRA, Minoxidil 5% cutaneous solution (SmPC and package leaflet).
Online care
Talk it through with us
Our doctors can see you by video, look at your hair loss, go through your medical and mental health history, and help you weigh up the options without any pressure.
If you do decide on finasteride, we'll keep checking in with you, including on how you're feeling, not just how your hair is doing. Some cases need an in-person examination, and your doctor will tell you if yours is one of them.
Book a hair loss consultation to talk through the benefits, the side effects and the alternatives with one of our doctors.
Support
If you're struggling right now
Reporting
Reporting side effects
If you think you're having a side effect, talk to your doctor or pharmacist. You can also report it yourself to the Health Products Regulatory Authority (HPRA) at www.hpra.ie, using its online form. The HPRA guide for patients and carers explains how, and you can report even if you're not sure the medicine caused the problem. The HPRA cannot give clinical advice, so speak to a doctor about your symptoms too. Every report helps make medicines safer for the next person.
Care in Ireland
Talk to a doctor about hair loss
A video consultation can look at your hair loss, your medical and mental health history and your options, including the choice not to treat it.
Thinking about finasteride? Talk it through first.
Go through your hair loss, your history and the possible side effects with one of our doctors by secure video, with no pressure to start treatment.
Sources
Evidence behind this article
Sources checked on 24 October 2026.
The EMA review and the HPRA notice cover finasteride and dutasteride; this article covers finasteride only. The HPRA notice is a direct healthcare professional communication from the marketing authorisation holders, published on hpra.ie. Product details come from one authorised Irish finasteride 1 mg tablet and one Irish minoxidil product, and other brands may differ. This article describes the risks and what a consultation can cover; any treatment decision is made by a doctor after an individual assessment.
Questions
Common questions about finasteride side effects
What are the main finasteride side effects?
Most men have no problems. A minority notice mood changes, including low mood and, less frequently, suicidal thoughts, or sexual effects such as a lower sex drive, difficulty with erections and less semen. Breast tenderness or enlargement, allergic reactions and testicular pain have also been reported. If your mood changes, stop taking finasteride and talk to a doctor.
How long do finasteride results take?
Most men don't see much change for the first three to six months, and it's usually around the one-year mark that you can properly judge whether it's working. It is best at holding on to the hair you have, and it is less likely to rebuild a hairline that has already receded a long way.
Does finasteride hair regrowth last if I stop?
No. It only works while you take it. If you stop, any hair you have kept or regrown will usually be lost again over the following year or so.
What is post-finasteride syndrome?
It is a name used online for symptoms that continue after finasteride is stopped. The Irish product information we checked does not use that name, but it does list sexual problems that continue after stopping as reported side effects, with a frequency that cannot be estimated. If you notice symptoms like these, tell a doctor early.
Is topical finasteride linked to suicidal thoughts?
The 2025 EMA review found no evidence linking finasteride skin spray to suicidal thoughts, and the HPRA notice says there is insufficient evidence to support a causal link. That finding is about suicidal thoughts only. Whether topical finasteride suits you is worth discussing with a doctor.
Can I use minoxidil and finasteride together?
That is a decision for a doctor who knows your history. They are different medicines that work in different ways, and minoxidil has its own cautions: the Irish leaflet says not to use it if you have high blood pressure, and the product information says not to use it with other medicines on the scalp.
