While minoxidil (Rogaine) works by nurturing the hair follicles back to health, it does not grow new hair. Unlike Rogaine, finasteride (Propecia) is a prescription medicine in most markets, and one of the few that can actually stimulates new hair growth in patients with male pattern baldness. Its effectiveness became known when men taking it for prostate issues grew new hair. Women have not been proven to benefit from Propecia; however, more studies are needed and some doctors have indeed used it on female patients and reported good results. A potential risk of side effects exists for pregnant women who handle broken or crushed tablets, though this risk seems to be very low and only relevant in cases of repeated contact over a long period of time. The substance can be absorbed through the skin and may cause damage to a male foetus. Studies have shown no apparent risk for the male who is trying to get a woman pregnant – he can continue using the medication.

Let’s take a look at how finasteride works. The cause of genetic pattern baldness is caused by a hormone called dihydrotestosterone (DHT), a by-product of testosterone. Therefore, substances which act as DHT-blockers have been shown to decrease the negative effects of DHT on hair growth. When the body metabolizes testosterone it breaks down into DHT. The enzyme 5-alpha reductase (5RA) supervises this chemical reaction. Propecia causes 5AR to become less effective, reducing the body’s ability to produce DHT. After five years of regular use almost 50% of men with male pattern baldness showed an increase in hair growth while 90% of men maintained hair pre-treatment levels.

Finasteride taken at 1mg per day has been proven clinically to decrease DHT by nearly 70%. Some experts believe finasteride lowers testosterone levels; however, it has actually been shown in most studies to raise levels by around 9%, which is still in the normal range.

Hair re-growth usually occurs in younger patients who have recently lost hair. Like other hair growth products, finasteride will work as long as it is ingested daily. Discontinuation of positive effects will occur if treatment is interrupted and the hair loss will slowly start again. Interestingly, it appears then men who take the drug during “high level” years and then stop once reaching a certain age will suffer only minimal loss. In other words, if the drug treatment is stopped after those years of high potential hair loss, the resumption of loss will be negligible and the patient will have effectively avoided much of the loss altogether.

Side effects with a standard 1mg daily dose are rare and usually not permanent. Some men have demonstrated some form of sexual dysfunction such as decreased libido, erectile dysfunction or decreased volume of ejaculate. However these results do not vary significantly from men treated with a placebo in actual studies, so reports on many Internet sites appear to be highly exaggerated. In fact, some doctors believe it best not even to mention these side effects, as they are more psychological than physical. Another rare side effect is breast tenderness or enlargement that has occurred in about 0.4% of men that was not greater than the control group. All side effects subside when finasteride is discontinued. Sometimes doctors can reintroduce the medicine by starting with small doses and gradually increase until symptoms appear.

How Does Finasteride Work?