Home > News >

Understanding Finasteride (Propecia) Side Effects

Box of accord branded finasteride (28 tablets) with few loose tablets scattered in front of it
Written by

Content by

Medically approved by

Authored by

Last Updated

Last Updated

Science means that hair loss can be optional...

No fancy packaging. No unwanted subscriptions. Delivered discreetly.

Shop Hair Loss

Table of Contents

Finasteride is a popular hair loss treatment  for men and is one of the few drugs that has been approved for treating male pattern baldness, also known as Androgenetic Alopecia. This is characterised by gradual thinning of the hair on the scalp, eventually resulting in a receding hairline or balding. Medical studies have shown finasteride to be effective in 83% of individuals that take it, either slowing down the balding process, or reversing it. But what are the side effects of finasteride?

 

Common Side Effects of Finasteride

According to the Patient Information Leaflet, the following side effects may occur:

  • Loss of sexual desire
  • Difficulty getting an erection
  • Decrease in the production of semen
  • Depression

These side effects are classified as ‘common’, which means that around 1%-10% of finasteride users may experience them. This also applies to Propecia, the brand name for finasteride. All drugs come with a risk of side effects and there appears to have been a lot of negative press surrounding the use of finasteride.

We decided to look at the side effects that finasteride may cause in more detail.

Does Finasteride Cause Sexual Side Effects?

The use of finasteride has been associated with sexual dysfunction, such as loss of sex drive and erectile dysfunction. It is important to note that most studies looking at the side effects of finasteride include the higher dose of 5mg. This dose is used to treat BPH (benign Prostatic Hyperplasia), an enlarged prostate. It is also important to note that the condition BPH can cause erectile dysfunction and other sexual side effects.

A study published in the British Medical Journal researched the risk of erectile dysfunction over a  9-year period, in men taking both finasteride 1mg and 5mg. The conclusion was that there was no obvious link between erectile dysfunction and finasteride at either dose.

Another study that analysed sexual side effects 1mg tablets, found that 4.4% of patients experience sexual side effects in comparison with 2.2% in the placebo group.

A study looking at the sexual side effects of 1mg tablets found that 75.7% of men experienced no sexual dysfunction, 21.6% experienced mild dysfunction and 2.7% reported sexual dysfunction. In non-finasteride users, sexual side effects were higher with 61.6% experiencing no sexual dysfunction, 26.3% experiencing mild dysfunction and 12.1% experiencing sexual dysfunction.

One study suggests that sexual side effects were higher in patients taking finasteride who had been informed about potential side effects. This was in comparison to a group of patients who were not informed of any sexual side effects before starting treatment. The psychological impact of knowing that a drug can potentially cause sexual side effects can also impact patients. This is known as the nocebo phenomenon, where negative expectations of a treatment can lead to side effects. This study suggests that the fear of developing sexual side effects can bring about or enhance these adverse effects.

Ultimately, research on the impact of Finasteride on fertility yields varying conclusions. Finasteride works by blocking an enzyme in the body called 5-alpha-reductase. This enzyme is responsible for converting testosterone into another hormone called dihydrotestosterone (DHT). Studies indicate that this effect on testosterone levels, particularly through the lowering of DHT, may influence sperm production.

Is Depression a Side Effect of Finasteride?

There is limited research that has investigated mood changes in those taking finasteride 1mg tablets. Mood disturbances have been reported in a minority of individuals, but the scientific research around this area is limited. Similar to the sexual side effects, there are conflicting reports. Some reports and studies have shown that finasteride can cause erectile dysfunction, which may lead to a drop in mood. At the same time, some reports and studies have shown that finasteride does not affect mood at all.

Are Finasteride Side Effects Permanent or Reversible?

Most research shows that side effects are not permanent and are usually reversed when treatment is stopped. Finasteride has a short half-life of around 7 hours and in theory, it will leave your body after one and a half days. However, finasteride accumulates in your system and it can take slightly longer. Because finasteride leaves your body relatively quickly, side effects should go away shortly after stopping treatment.

Can I Take Finasteride if My Partner is Trying to Conceive?

If your partner is trying to become pregnant, there is no evidence that finasteride will make it harder to conceive, or that there is a risk of birth defects to the unborn child. There have been concerns previously, but evidence from scientific research has not been able to prove this. Pregnant women should not handle finasteride, as crushed or broken finasteride can be absorbed and can potentially cause harm to the development of sex organs of the foetus. Although the amount of finasteride in sperm is minimal and not considered to be harmful, you should use a barrier method such as a condom if your partner is pregnant or planning to get pregnant as a matter of caution.

Will Finasteride Cause Cancer?

There is an ongoing debate about whether finasteride causes cancer or prevents it. A study conducted over 10 years found that finasteride reduces the risk of developing prostate cancer by 25%. However, during the trial, the incidence of developing ‘high-grade’ cancer was higher in the group that took finasteride. The argument for this is that finasteride shrinks the prostate, and sampling a smaller area increases the likelihood that the cancer sampled from a smaller area is likely to be more aggressive. Another argument for this is that finasteride improves sensitivity to the PSA test (the test that is used to detect cancer of the prostate). This can also have contributed to these findings.

However, a professor in urology from John Hopkins Medicine has argued that this study is flawed and finasteride hides the level of PSA (the markers that are used to detect prostate cancer). Therefore, it provides a false sense of security as PSA markers are lowered, but this does not reduce the risk of developing prostate cancer. Hiding these markers will not have a direct impact on preventing prostate cancer but make it undetectable at an early stage when it is curable.

Research in this area is conflicting but the consensus is that finasteride lowers the risk of developing prostate cancer and increases the risk of developing high-grade prostate cancer. Finasteride also increases the risk of breast cancer. It is important to discuss these risks with your healthcare provider before starting treatment with finasteride.

Serious Side Effects

It is rare for finasteride to cause a serious allergic reaction. However, if you experience any symptoms of an allergic reaction, you should seek medical attention urgently. These include:

  • Swelling of the lips and face
  • Rash
  • Itching
  • Difficulty breathing or swallowing
  • Dizziness

Any changes in the breasts such as increased size, lumps, pain, or nipple discharge should also be reported to a health care professional.

Side Effects After Stopping

Stopping finasteride will reverse the effects of any hair growth you have seen. In most cases, any side effects will also be reversed. This is because finasteride has a short half-life and leaves the body quickly. So after around 7 days of stopping finasteride tablets, you should notice that any unwanted effects disappear.

Long Term Side Effects of Finasteride

Most of the studies demonstrate that finasteride has a good safety profile, with a low chance of experiencing side effects. Those that do experience side effects, will find that they go away once treatment is stopped. However, there are a few reports, which suggest that finasteride can cause long term side effects.

Is Finasteride Safe to Take?

There are reports of some men experiencing side effects that mainly relate to sexual dysfunction, such as loss of sex drive, ejaculation problems and erectile dysfunction. It is important to note that most of these studies are carried out using finasteride 5mg used for BPH and not with finasteride 1mg. Most of these studies do not look at data from before these men started taking finasteride; and reports in newspaper articles and blogs do not analyse important data such as BMI, age and pre-existing medical conditions, which can all play a part. Pre-treatment surveys are important in gathering accurate scientific data. As a man gets older, his sexual function decreases.

However, there are reports of sexual dysfunction and we must acknowledge that there are some studies that show finasteride does cause such side effects, albeit in a small number of cases. These effects are usually mild with large studies indicating that they do improve with time; and that they are reversible when treatment is stopped.

Many large studies have shown no link in the cases of prostate cancer when taking finasteride, but a possible rise in high-grade cancer. Some studies also suggest that finasteride lowers the risk of prostate cancer.

There is a lack of evidence to suggest a direct link between finasteride and depression, but some small studies suggest that there may be a correlation. For this reason, depression is listed as a warning on the patient information leaflet.

All medication, including over the counter remedies for minor ailments such as coughs and colds come with a risk of side effects. Most people will never read into the side effects of these medicines and will never have a problem. If they read the list of side effects, they may not want to take the medication. Finasteride is no different and many men take it without any problems.

Male pattern hair loss can have negative psychological impacts and finasteride has helped to reverse and slow the balding process for many men. If you are taking finasteride, or wish to start, you should discuss any concerns relating to its use with your doctor or pharmacist first. Ultimately, the patient should be provided with as much information and knowledge as possible, so that they are empowered to make their own decision about starting treatment with finasteride.

If you experience serious side effects or an allergic reaction when taking Finasteride tablets, please seek medical attention and report side effects to your doctor or pharmacist.

If you are interested in trying finasteride you can start a free online consultation with Chemist Click. Our qualified pharmacists use a tailored approach to determine the best hair loss treatment according to individual circumstances and needs.

Sources

  1. https://www.cancer.gov/news-events/cancer-currents-blog/2019/prostate-cancer-prevention-finasteride-parnes
  2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3481923/
  3. https://academic.oup.com/jcem/article/101/12/4669/2765035

Whilst all of our content is written and reviewed by healthcare professionals, it is not intended to be substituted for or used as medical advice. If you have any questions or concerns about your health, please speak to your doctor.

We use cookies to analyse data and personalise your visit, learn more in our privacy policy