Doctor,

Have you ever heard of Propecia causing TE?

No, I have not.

Minoxidil is a vasodilator and is topical. Nitric oxide (Arginine-alpha ketaglutarate) is a vasodilator and oral.

I am having a hard time understanding why Minoxidil can grow hair (although I don’t know if it’s the same kind of hair and not just small hairs) while nitric oxide and massage typically aren’t viewed as hair loss treatments right now? You said before that Minoxidil probably works in that it prolongs one of the hair phases, but if they’re both nitric oxide based, what makes Minoxidil so different?

Minoxidil has hair growth as a side effect of the drug and I believe that it has nothing to do with its vasodilating properties. Minoxidil’s reason for growing hair is still not entirely clear.

My role on this blog is to explain what is known in research and clinical medicine, but the use of nitric oxide is not known as a hair loss treatment and to my knowledge has not been scientifically studied. You can sponsor it if you wish, but the drug companies that do this work are apparently not paying for the research.

Is the reason Propecia only blocks about 80% of DHT because the remaining 20% is Type I DHT and not Type II DHT?

No, it is because the way this particular drug (finasteride) works is through competitive inhibition with DHT. To understand this, look up competitive inhibition of drugs, or look at this page. Without getting too technical, this process makes it almost impossible to get 100% block from drugs like finasteride, because the drug and DHT are constantly competing for the binding site on the enzyme 5 alpha-reductase.

Dear Doctor,

i started using ZMA, a supplement which contains zinc, magnesium and vitamin B6. It is considered to be helpful for athletes, as it increases muscle strength. It is also claimed, that it increases testosterone levels. Since i take 1/4 proscar daily,i would like to ask you if it is possible possible to counteract with finasteride.( dht etc)

i thank you in advance.

With a good finasteride block and your adherence to daily use, the supplements you are talking about should not impact the value of the finasteride.

Hey Doc.,

I have a question regarding the shedding after quitting propecia. Why is it that when one quits propecia the shedding occurs much more rapidly then the natural progression of hair loss? That is, why don’t we go through the same “minituarization” that normally occurs with hair loss?

You cannot escape genetic balding. Hair has a normal life expectancy (see this post) so when the Propecia is withdrawn, the apototic process kicks in. Medications such as Propecia slow this process down by preserving or strengthening the dying miniaturized hairs (the hairs that are genetically programmed to die and fall out). When you no longer take the medication, all the genetically predisposed hairs that should have fallen out naturally will no longer be supported by Propecia. As such, they will fall out. That is a simple way of thinking about catch-up hair loss. In other words, you didn’t stop the time line of genetic hair loss by taking Propecia.

Hi Doctor,

I’m a 23 y/o male with hairloss beginning from the age of 20.

I’ve been on Generic Propecia (Finpecia) for aboout 4 months now and have noticed a gradual depletion of my libido to the point now where it is at absolute zero! There are a lot of sources saying that I will have difficulty regaining any form of sex drive for quite sometime (years!?) and obviously your response ‘that it should subside within several months’. I understand you’ve answered this question before, however you haven’t given a medical explanation as to why it should subside and considering I’ve had a gradual decrease in my libido for several months I’m simply not sure what I should believe.

Loss of libido at such a young stage of life is obviously very concerning to me and to many of your readers. I beg you to shed some light about this problem.

There is no medical explanation to why you will have a prolonged (several months?) residual side effect after stopping finasteride. Finasteride lasts in your blood stream for about a day. After a couple of days, it is essentially gone, but there is some tissue fixation which may keep it in some of your body tissues for about a week or so. The short duration for blood levels is why you need to take it every day for it to work. So if you had a side effect, it will likely subside within a few days (not months or years) after stopping the medication. Of note, side effects can go away even if you continue taking the medication.

I realize people write about libido issues related to finasteride (Propecia) and post concerns on the Internet. While I believe these people are having libido issues, I have a hard time believing that there is a direct correlation between finasteride (Propecia) and its long term side effects on libido. As a physician, I have followed and seen many patients over the last 10+ years who have been taking finasteride (Propecia) and I do not see the long term libido problem that people write about on the Internet. Yes, a small percentage of my patients (1 to 2 percent) may complain of sexual side effects, but the side effects usually go away after a few days or weeks (not months or years) and it is not permanent and a few canm not tolerate the drug for this reason. If there was such a long term or permanent problem with Propecia, I am sure I would have seen at least one patient in the last 10+ years describe this to me, and that has not been the case.

I strongly urge you to talk to the doctor that prescribed you the medication. The most important thing that people do not consider is that it may NOT be the medication that is causing a low sex drive. Many men (even in their 20’s) have sexual problems, but there’s not a great percentage of them that would admit it. While it may be easy to just blame the problem to a side effect from a drug, it can be a sign of a serious undiagnosed medical condition (such as high blood pressure, diabetes, depression, low testosterone, the presence of other diseases, etc). So although I appreciate the overall confidence many people have in me because I listen to (or read) what they are saying, you need a doctor willing to take you on as a patient — someone to meet with in person, not just communicate via email.