This medication has been on the market for almost twenty years and has an excellent record for safety. In slightly larger doses, it is used for the treatment of prostate cancer. If you are planning to have a test to see whether you have this cancer, propecia can mask the results. Always tell the doctor performing the tests that you are taking this medication. More generally, as with any other prescription-only medication, it is impossible to rule out adverse side-effects altogether. However, this medication is better than many others with only about 1% of the men who take propecia experiencing any side-effects. Unfortunately, those side-effects do give rise to slight concerns. If you experience any of the following, you should seek medical advice on whether to continue the treatment.

For the most part, the symptoms are sexual. The first sign is likely to be a loss of libido, followed by a reduced amount of semen in ejaculation. This can be followed by a rash and itchiness in the groin, some swelling in the testicles and pain when an erection is formed. If you continue to take propecia there is a risk of erectile dysfunction. There is some evidence suggesting that sexual damage may not be reversible. In very rare cases, there is an enlargement of the glands in the male breasts and some tenderness will follow.

Because of its potential effect on male sexuality, it is dangerous for women to come into contact with this medication while they are pregnant. This medicine can significantly affect the development of male foetuses. This warning is not only given to women as potential takers of the medication. In powder form, it can be absorbed through the skin. Thus, the medication should always be stored in a sealed container and opened only by a man. If a tablet is broken, care should be taken not to allow any powder to fall on to any surfaces where women might accidentally come into contact with it.