If Propecia’s Half-Life Is Short, How Can It Be Effective?

Hi, Dr Rassman.

I’m a caucasian male, 30 years old.

Can thyroid problems hasten or kick start the balding process? I’ve been diagnosed with hypothyroidism and have experienced early signs of MPB around the same time. No member of my immediate family has severe hair loss and certainly hadn’t lost any by age 30.

If propecia’s half life is so short, and only reduces DHT in the body modestly, for only part of the day, why then can it be so effective at treating hair loss? Are there other, hidden attributes to Propecia that we do not yet understand that is helping millions of men stave off the shiny dome?

Thanks, Doc. You have a great site, and I’m a daily reader!!

Thyroid problems can precipitate hair loss and hair texture.

You are correct in stating that Propecia’s half life is short (about 4-5 hours). That is why you need to take it everyday. There is also tissue fixation of the drug that probably reflects a longer tissue hair life (not easy to measure) that may hold the effects on the hair follicles. The testing on hair regrowth and hair counts were done with various doses from 20mgs per day down to less than 1 mg per day. The results were published showing that the 1mg dose was as good as a higher dose in treating hair loss. As many of you know, finasteride is packaged in a 5mg dose as Proscar (or generics), which is used for treating prostate disease. Seeing as how Propecia is the same medication, it may also help your prostate health.