Finasteride

Finasteride is a synthetic antiandrogen that inhibits type 2 5-alpha reductase. This is the enzyme that converts testosterone to dihydrotestosterone or DHT. It is used in high doses to treat prostate cancer and in low doses to treat benign prostatic hyperplasia or BPH.

Proscar was the first finasteride product to be approved in back in 1992. It was marketed then as a treatment for prostate enlargement. Later in 1997, low doses of around 1mg was shown to stimulate hair growth in male pattern baldness. It was marketed by Merck under the brand name Propecia.

Finasteride and Hair Loss

In a five year study conducted on men experiencing mild to moderate loss of hair, half of those treated with Propecia(1 mg) experienced some regrowth of hair, and a further 42% experienced no further loss of hair. The majority of men who took Propecia reported that their bald spot got smaller, their hair loss slowed, and its appearance improved. In the treatment group, the average hair count remained above baseline. It also showed an increasing difference from hair count in the placebo group, for duration of the study^[1].

Propecia has been shown to work on the hairline and on the crown area of the scalp, with emphasis on the crown area^[2].

Finasteride for hair loss seems to only be effective for as long as the user continues to use it. Hair is usually lost with six to twelve months of discontinuing therapy^[3].

Finasteride Side Effects

About 1% of users experience side effects while on finasteride. These include erectile dysfunction and sometimes gynecomastia(male breast enlargement), although gyno is far less common. Side effects usually cease after discontinuation of treatment, which is rather short considering the drug has a half life of six to eight hours.

Finasteride should not be used by women due the possibility of birth defects. The medication can even be absorbed throught the skin(transdermal), so pregnant women should not handle the medication.

Finasteride has also been linked to depression^[4].

References Cited

1. http://www.propecia.com/finasteride/propecia/consumer/index.jsp

2. Layden J, Dunlap F, Miller B, Winters P, Lebwohl M, Hecker D, et al. (in press). "Finasteride in the treatment of men with frontal male pattern hair loss". J Am Acad Dermatol.

3. Rossi S (Ed.) (2004). Australian Medicines Handbook 2004. Adelaide: Australian Medicines Handbook. ISBN 0-9578521-4-2.

4. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1622749