Propecia Side Effects

What Are the Side Effects of Propecia?

Propecia is a drug used to treat hair loss in men. It is an oral medication, taken once a day, and available on prescription. It is prescribed to stimulate hair growth in men with male pattern baldness.

Propecia’s active ingredient is finasteride, and it was originally developed to treat a condition which causes enlarged prostate glands in benign prostatic hyperplasia.

Finasteride works by reducing dihydrotestosterone (DHT) levels in the scalp. The hormone DHT contributes to male pattern baldness, and Propecia medication helps to reverse the hair loss process by decreasing the effect of DHT on the hair follicles.

It takes around three months to see any results from using Propecia. It is recommended for men over the age of 18 only and must not be taken by women.

Millions of patients take Propecia with no side effects, or minimal and reversible side effects.

Dr Simran Deo Medical Editor

Medically reviewed by

Dr Simran Deo

Last reviewed: 02 Apr 2020

What Side Effects Does Propecia Cause?

Common ( affecting 1/100 people) side effects are:

  • erectile dysfunction
  • low libido (sex drive)
  • decreased volume of ejaculate

These side effects usually disappear when you stop taking the medication.

The frequency of the following side effects of Propecia is not known:

  • breast swelling or tenderness
  • palpitations
  • changes in liver function noted on a blood test
  • testicle pain
  • depression
  • male infertility
  • poor sperm quality

It has been reported that sexual side effects of Propecia include erectile dysfunction, reduced libido and ejaculation problems and these may continue after you have stopped taking the drug, although this is rare according to studies. If you have any concerns about side effects you must speak to your doctor.

Can it Have Permanent Sexual Side Effects?

There is currently no conclusive evidence to show that the side effects of Propecia such as loss of libido and erectile dysfunction are permanent but the FDA have advised that they do continue after stopping the medication.

It has been reported that taking finasteride, the active ingredient in Propecia, may be linked to prostate cancer. A decade ago, a study called the Prostate Cancer Prevention Trial (PCPT) suggested that finasteride may decrease the risk of low-grade prostate cancer but may increase the risk of high-grade prostate cancer.

However, a 2015 study researching the link between finasteride and prostate cancer found that there was ‘no association between finasteride concentrations and the risk of getting any type of prostate cancer risk.

If you are taking Propecia and have any concerns about your risk of prostate cancer, please speak to your doctor.

Does Propecia Cause Breast Enlargement or Breast Cancer?

Male breast enlargement (gynaecomastia) has been reported by some men using Propecia and there have been rare reports of breast cancer developing while taking the drug. However, there have been no cases of male breast cancer associated with Propecia reported in the UK to date. 

Can it Cause Birth Defects?

Propecia must not be taken or handled by women as it may cause genital birth defects in male babies. It must not be handled by pregnant women or those planning to become pregnant. This is because it is a medication with an active ingredient that affects the body’s hormonal system.

Propecia tablets are coated so during normal handling the active ingredient can’t touch or penetrate the skin as long as the tablet isn’t broken. If a woman comes into contact with a crushed propecia tablet, they should immediately wash their hands thoroughly.

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