what are the questions one would ask a doctor if he wanted to be sure he wasnt having a hypoandrogenic reaction to propecia? what would a doctor check, or know to find this out?

im a 25 year old male and ive been on propecia for 15 months or so. Hair has thinned quite alot while on treatment, instead of second guessing myself and reading to many websites.

i just want a medical answer! thanks for the help doc!

You need to tell your doctor what you are experiencing. Testosterone levels transiently go up with Propecia as compensation to the impact of DHT blocking. Are you asking if developing breasts is a problem with Propecia? Your questions are not clear.

Hi Dr Rassman,

I have repeatedly heard you mention that propecia has a half life of 4-5 hours. If finasteride were to leave the body within 5 hours, how long will it take to restore DHT levels and other affected hormones to their initial levels? If the whole process needs 3 days maximum, why does it take some time for some patients to recover from some sexual side effects?

Could you please provide an authorative refernce for finasteride’s half life?

Thank you

The half life of finasteride is about 4-5 hours. It means that after medication is absorbed and distributed throughout the body, it take about 4-5 hours for your body to get rid of half of it from the blood stream. At the molecular level, finasteride attaches to the enzymes 5 alpha reductase (Type I and II) and makes them less effective. The turn over for the enzyme complex is slow and it takes almost 30 days for Type II and 14 days for Type I enzyme-medication complex. (Source: RxList.com – Propecia)

That is why it takes days until the actual effects of the medication are eliminated.

My understanding is that the Dominican Republic population that didn’t suffer from/was immune to MPH (as well as prostate cancer) was deficient in the Type II AR enzyme. Their bodies simply didn’t produce it. Are we to assume then that there was some DHT in their bodies produced via the Type I enzyme?

If that’s the case, why is there speculation that reducing the Type I enzyme (ie. through dutasteride) is considered possibly more effective at preventing hair loss (independent of the fact that dutasteride reduces more of Type II)? In otherwords, who cares about Type I if it didn’t affect the Dominicans?

thanks.

Dominicans are not immune to prostate cancer. Asian countries have the lowest incidence of prostate cancer, while western countries stand on the top to the list. I think you are referring to the particular Dominican kindred that were found to have alpha reductase type 2 mutations in 1974. These patients initially were diagnosed to have problems with developing their male genitalia. DHT has an important role in development of the genital system before puberty.

Both types one and two of the enzyme alpha reductase convert testosterone to dihydroxytestosterone (DHT) and it seems that blocking both of them works better on hair loss treatment. As we said before, due to its higher rate of side effects dutasteride is not FDA approved for treatment of male pattern baldness as of yet.

Inhibition of both these enzymes is also proven to be more effective against benign prostatic hyperplasia (BPH).

For further reading, please visit:

1. PubMed – 5 alpha-reductase-2 gene mutations in the Dominican Republic.
2. PubMed – The importance of dual 5alpha-reductase inhibition in the treatment of male pattern hair loss: results of a randomized placebo-controlled study of dutasteride versus finasteride.
3. PubMed – A large retrospective analysis of acute urinary retention and prostate-related surgery in BPH patients treated with 5-alpha reductase inhibitors: dutasteride versus finasteride.