Dr. Rassman, I had a few questions about the use of Propecia: You claim in other posts that the half-life of the drug is four hours, and that by then it will be out of your system – and while I claim no knowledge of drugs or physiology, it seems to me that if the drug had a half life of such a small amount of time the dosage would be more freqent than 1mg a day. Wouldn’t the beneficial effects be flushed from your system well before 24 hours? And wouldn’t any side effect (in my case: low libido, dull groin/testicle pain) go away the first day you skipped the pill? Thanks!
Although a half life is 4-5 hours, there may be tissue levels that exceed the half life. I believe that there are such tissue levels and that these are maintained for a few days after you stop taking the pill. However, I do not know if anyone knows the effectiveness of these tissue levels. Some people who have negative sexual side effects do tell me that it took a week or two for it to go away. Is that psychological? No one knows for sure. I would imagine that a half pill twice a day may be better than a pill once a day. There are suggestions that even smaller doses work. The science is lacking so we have little help in understanding anything that the FDA does not validate as safe and effective. You will have to trust Merck, which is a good company, but obviously biased.