Finasteride Side Effects: Everything You Need To Know Before Using The Hair Loss Treatment

Scott McDougall
Scott McDougallMPharmDirector & Registered Manager
finasteride side effects

If you suffer from hair loss or male pattern baldness, then you’ve probably heard of the hair loss treatment Finasteride. This prescription-only medication is extremely effective at tackling hair loss and even promoting regrowth and Finasteride side effects are generally uncommon.

Although the risk of experiencing these side effects is low, it’s important to be aware of how this treatment could potentially affect you, and how likely you are to experience any side effects.

On this page, we’ll be talking about the common side effects of Finasteride in detail so that you know exactly what to expect if you decide to use this treatment.

Click through if you are looking for answers to the question of what is Finasteride used for?

Common Finasteride side effects

Each individual is different, meaning we can all react to the same medication in different ways. Some users of Finasteride will not experience any side effects at all and will have an extremely positive experience with the medication. To find out how real users got on with Finasteride, you can go to our Finasteride reviews page.

However, there are some possible side effects that you may experience if you decide to use Finasteride to treat hair loss. Some people may experience the most common or more unusual side effects of using this treatment.

Here are some of the known side effects of Finasteride:

Uncommon frequency (affects between 1 and 10 people of every 1000)

  • Decrease in sex drive
  • Depression or lowering of mood
  • Impotence — difficulty in achieving or maintaining an erection
  • Ejaculation disorders – such as problems ejaculating or reduced volume of ejaculation

Unknown frequency

  • Hypersensitivity reactions — such as hives, itching, rash, or swelling of the face and lips
  • Heart palpitations
  • Tender or swollen breasts
  • Testicular pain

The frequency of the above effects (listed under ‘unknown frequency’) is not currently known as there is not enough data available. That said, these effects are thought to be very uncommon, and rarely occur.

The likelihood of experiencing any of the above side effects can vary from user to user; what one individual may encounter could be completely different from another.

If you have been taking Finasteride and you are concerned about any reactions or side effects you are experiencing (particularly if they feel severe, long-lasting or painful), then you should consult your doctor for further guidance.

Sexual health side effects

Finasteride has been known to produce side effects in the sexual health of the men taking it. Finasteride can potentially cause decreased libido, impotence, erection difficulties and ejaculation problems.

These are the most common side effects of Finasteride; however, even these are very uncommon, affecting between 1 and 10 people of every 1000 users (less than 1%).

Most of the time, these side effects will appear within the first year of using Finasteride — but if you are concerned at all, you should speak to your doctor.

Finasteride and memory loss

In some very rare circumstances, Finasteride has been linked to memory loss.

This tends to be part of a wider problem known as post finasteride syndrome (PFS) which is experienced by a very small percentage of men who take Finasteride.

PFS is made up of a range of persistent sexual, physical, neurological and mental adverse reactions — including memory loss and other cognitive difficulties.

It is extremely rare to suffer from this condition and experience memory loss.

Finasteride and prostate cancer

Initial study findings suggested that Finasteride was linked to an increase in prostate cancers. Since then, however, further research has been carried out that has disproved this theory.

In fact, Finasteride has been found to significantly reduce the risk of prostate cancer, and may even prevent it. Follow-ups in trials were carried out over nearly 20 years and established Finasteride as an extremely safe and effective medication to use.

Finasteride and depression

There is a potential connection between Finasteride and depression; some users have reported an increase in mental health issues such as depression, anxiety, or panic attacks.

Most men who take Finasteride respond well to the medication; however, if you feel like Finasteride is causing you to have negative or depressive thoughts, you should stop taking the treatment and consult a doctor immediately.

If you have any existing mental health problems, it is not recommended for you to take Finasteride 1mg tablets to treat hair loss - Minoxidil topical solution may be more appropriate for you.

Finasteride shedding

Some users of Finasteride may experience an increased shedding of hair during the first three months of treatment (or sometimes earlier, in the first month of use). This initial shedding can last for a few months. This is a normal part of the hair cycle where thinner hairs make way for newer, thicker hairs in the follicle. You should notice that between 6 to 12 months after starting Finasteride, you have an increase in hair thickness and hair regrowth.

If you are concerned about excess shedding, you can seek advice from a medical professional.

Finasteride and pregnancy

Finasteride is only safe to use by men for the treatment of male pattern baldness — women cannot take Finasteride. This is because Finasteride could interact negatively with female hormones.

As a precaution, women are even warned not to handle Finasteride tablets, particularly if they are crushed or broken, to avoid absorption into the body. This is particularly important for pregnant women (or women who may become pregnant) because of the possibility of Finasteride absorption, which may be harmful to a male foetus. However, there are currently no adverse pregnancy outcomes in mothers exposed to Finasteride.

If you are a man taking Finasteride, and you and your partner wish to try to get pregnant, it would not be advisable as Finasteride can be present in the sperm. As such, it is always advisable to use a condom during sex whilst taking Finasteride and if you are thinking of trying for a baby to discuss it with your doctor before you start. If you are concerned or have any questions, you can speak to your medical team to confirm.

What happens after you stop using Finasteride?

Finasteride works by stopping your body from converting testosterone to dihydrotestosterone (DHT). DHT is the hormone responsible for male pattern baldness, so stopping the production of DHT will halt hair loss and can even promote hair growth.

Unfortunately, Finasteride isn’t a cure for hair loss, but an ongoing treatment. Although Finasteride is an effective hair loss medication, it only works while you are taking it.

This is because Finasteride only has a half-life of around five to six hours — which means that you will need to take a tablet daily to keep the levels of Finasteride in your body topped up.

If you stop using Finasteride, your body will begin to convert testosterone to dihydrotestosterone (DHT) again, and your hair loss may continue.

Is Finasteride safe?

Clinical research has shown that Finasteride is an effective hair loss treatment that is safe to use and has few side effects (which are uncommon).

For the majority of users, Finasteride is extremely safe to take, and will positively benefit the individual. However, in very rare circumstances, the use of Finasteride (and other finasteride-based medications) can result in a condition called post finasteride syndrome (or PFS).

PFS causes a complex set of symptoms; sufferers will experience a range of persistent sexual, physical, neurological and mental adverse reactions. For more information about PFS, you can read our post finasteride syndrome page.

It is extremely rare to suffer from this condition, and the vast majority of Finasteride users will only experience very mild side effects, if any at all.

If you are unsure about taking Finasteride, you can speak to a medical professional who will be able to advise you.

The difference in Finasteride dosage

You may have noticed that Finasteride is sometimes available in two different doses: 1mg and 5mg.

So what exactly is the difference between Finasteride 1mg and 5mg?

You might think that a 5mg dose of Finasteride would be a stronger, more effective way of treating hair loss, but it’s actually used for a completely different condition; Finasteride’s other medical use is to reduce the symptoms of an enlarged prostate gland.

The dosage of Finasteride for prostate treatment is higher than the dosage used for hair loss: 5mg is prescribed to men with an enlarged prostate.

Finasteride 5mg should not be used to prevent hair loss as it is no more effective than Finasteride 1mg tablets, but has a higher risk of side effects.

At The Independent Pharmacy, we only provide Finasteride 1mg tablets specifically for treating hair loss and male pattern baldness; we do not currently offer Finasteride 5mg for treating enlarged prostate gland. For more information, please go to our Finasteride dosage page.


If you suffer from hair loss or male pattern baldness and you’re looking for an effective treatment with clinically proven success, then Finasteride works.

Finasteride has some known side effects, but these are uncommon and many Finasteride users do not experience any negative side effects at all throughout the course of treatment.

If you encounter any of the side effects of Finasteride that we’ve mentioned above, you should contact your doctor for advice on how to proceed. They may suggest stopping your course of treatment and trying another type of hair loss medication.

If you think Finasteride may be the right treatment for you, you can get in touch with The Independent Pharmacy and buy Finasteride after completing a free online consultation.


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