Propecia belongs to a group of medicines called Type II 5-alpha reductase inhibitors. It contains the active ingredient finasteride. Propecia is prescribed if you have male pattern hair loss (also known as androgenetic alopecia or AGA). Propecia helps increase hair growth on the scalp and prevents further hair loss in men. Men with mild to moderate, but not complete hair loss, can benefit from using Propecia.
Dihydrotestosterone (DHT) is a male sex hormone. 5-alpha reductase is an enzyme which makes DHT in the hair follicles. Men who have less Type 2 isoenzyme of 5-alpha reductase within their body's do not develop AGA (male pattern baldness).
However, Type 2 5-alpha reductase has been found within the scalp hair follicles, and balding scalps in particular have been found to contain more Type 2 5-alpha reductase activity and DHT levels. This is believed to be the reason for male pattern baldness.
Finasteride has been shown to inhibit the human Type II 5-alpha reductase, decreasing the formation of DHT from testosterone and thus helping to inhibit balding.
How does the hair on your head grow?
Hair grows at the rate of approximately 1 centimetre (half an inch) every month. Hair grows from hair follicles, which are located under your skin. There are 3 phases to hair growth. The growth phase lasts 2-4 years, followed by the rest phase which lasts approximately 2-4 months. After this, the hair falls out and in its place new healthy hair begins to grow, and the cycle is repeated.
What is male pattern hair loss?
Male Pattern Baldness/hair loss has a specific appearance usually consisting of a receding hairline and/or balding on the top of the head. This is believed to be due to the hormone DHT.
DHT reduces the length of the growth phase which then leads to male pattern hair loss. Some men can begin to experience it in their 20s and it becomes more common with age. But once hair loss has occurred over a long period of time, the hair may be permanently lost.
How does Propecia work?
Propecia reduces the levels of DHT in the scalp which helps to reverse the balding process, leading to increased hair growth and prevention of further hair loss.