Hair Restoration Blog

Q:

I have read an article on the active half life of finasteride, which is a few hours, but you mentioned in one of the posts that its side effects may last up to 5 days after discountinuing the drug. How do you explain that?

A:

Finasteride (Propecia) functions through blocking the enzyme, 5 alpha reductase. The enzyme five-alpha reductase is responsible for conversion of the male hormone, testosterone to dihydroxytestosterone (DHT), which is the form of the hormone affecting hair follicles and causing hair loss. That is true that finasteride gets eliminated from our body in a few hours, but its blocking effects on the enzyme 5 alpha reductase continues for a long time. If you ever experience side effects of finasteride, you can stop the medication and its effect will be gone in 5 to 6 days.

Q:

Hi Doctor,

Some doctors prescribe Dutasteride (Avodart) for hair loss prevention. I know you don’t recommend Dutasteride for hair loss for obvious reasons, but based on available research findings on this medication, what do you think are the most likely possible side effects from using Dutasteride if worse come to worse. Would it be like multitude of finasteride side effects? Again, I know your view of non-FDA approved drugs.

A:

Dutasteride (Avodart) is one of the selective inhibitors of the type I and II of the enzyme 5-alpha-reductase, the enzyme that converts the male hormone testosterone to 5-alpha-dihydroxytestosterone (DHT). In comparison with dutasteride, finasteride (Propecia) acts as an inhibitor of just type II of the enzyme 5-alpha-reductase, which is more specific. Studies around dutasteride mechanism of action shows that, blocking both type I and type II enzyme can be more potent that only one in reducing the levels of DHT in the body.

If you are taking dutasteride for other indications, you may get some hair growth as a good side effect. As you guessed I cannot recommend dutasteride solely for prevention of hair loss not until it is approved for hair loss treatment by FDA. Other than not being FDA approved my other reasons are:

1. The optimum dose of dutasteride for hair loss prevention is not determined.
2. The side effects of dutasteride are much more prominent comparing to finasteride.
3. If you are considering the cost effectiveness of dutasteride, with new price reduction of finasteride that should not be in the picture any more.