Why Does It Sometimes Take Longer for Some Patients to Recover from Propecia Side Effects?

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.