Common Propecia Side Effects Explained

What should Propecia do?

Propecia is a brand-name medication that contains 1mg of finasteride to treat hair loss in men with androgenetic alopecia (male pattern baldness). 

Finasteride 1mg works by blocking the production of dihydrotestosterone (DHT) in men with male pattern baldness to increase their hair growth cycle and prevent hair follicles from shrinking. 

You would usually start to notice visible signs of reduced hair loss within 3-6 months of starting Propecia. After a couple of years, you should have a less visible scalp.

How effective is Propecia?

If you are eligible for treatment and have no known allergies or health conditions that would put you at risk of experiencing side effects, Propecia is generally effective and well-tolerated. 

An expert panel review of clinical photographs shows that after 5 years, 90% of men using a finasteride (the active ingredient in Propecia) based treatment either maintained no further hair loss or sustained visible improvement. Conversely, 75% of men treated with a placebo sustained further visible hair loss at 5 years.

What side effects can Propecia cause?

Although uncommon (can affect up to 1 in 100 people), side effects of Propecia tablets may include problems with achieving or maintaining an erection, a decrease in sex drive, and problems with producing semen, such as a reduction in the amount produced. 

Some of these side effects may only be present during treatment, while others may persist after treatment is stopped. 

If your side effects don’t improve or cause you discomfort, we would always suggest making an appointment with your prescribing clinician to talk through any concerns.

Who is at risk of experiencing side effects?

Individuals with a history of depression, mood disorders, or erectile dysfunction may be more susceptible to certain side effects or notice a worsening of existing symptoms when taking Propecia and other medicines containing finasteride.

Regulatory bodies in the UK have issued safety communications to raise awareness of potential sexual and mental health side effects associated with finasteride 1 mg. Patients are advised to discuss any pre-existing conditions or concerns with a healthcare professional before starting treatment.

It is important to talk to your GP about your sexual and mental health beforehand to ensure Propecia is a suitable option for you.

Propecia must not be used by women. Finasteride can cause abnormalities of the external genitalia of a male foetus. Women who are, or may be pregnant should also avoid handling crushed or broken Propecia tablets due to the risk of absorption through the skin.  A very small amount of finasteride has been detected in semen, and studies suggest this level is unlikely to pose a risk to a developing male foetus.

How can the risk of Propecia side effects be reduced?

To reduce the risk of developing side effects when taking Propecia, it's essential that you take only the prescribed dose and follow all of the instructions in your patient information leaflet.

If you miss a dose of Propecia and it has been more than 6 hours since you were due to take it, miss this dose and wait until your next scheduled dose. Don’t take a double dose as this won’t improve the effectiveness of the medicine but may increase your risk of side effects.

If you’re concerned about experiencing systemic side effects (those which affect the whole body), an alternative hair loss treatment with fewer systemic side effects than Propecia tablets is an over-the-counter (OTC) topical hair loss solution such as Regaine for Men. Regaine for Men contains minoxidil 5% solution and it can be used for the treatment of androgenic alopecia (male pattern baldness) in men. Always read the leaflet supplied in the pack before using this product.

Is Propecia an option for you?

The best way to determine whether Propecia may be suitable for you is by having a consultation with your GP or clinician.

If the clinician assesses that Propecia is a safe and suitable option for you, you can consider it alongside other hair loss solutions when making a decision. 

Learn more about hair loss by reading our other articles on Health Hub or start an online consultation to explore your suitability for Propecia.