DHT: the Full Story
On the discussion forum of this site, people post many messages about DHT and ask how they can lower this derivative (metabolite) of testosterone at least in scalp tissue. These people attribute negative qualities to this hormone, the main one being the miniaturization or even the destruction of hair follicles. In this article I want to bring some complexity into the DHT debate and perhaps free people of the simplistic notion that DHT is all bad.
DHT is a steroid hormone just like testosterone but more powerful. It is manufactured mostly in the skin and in the liver. The manufacturing process involves the conversion of testosterone into DHT by an enzyme called 5-alpha reductase.
There are two chemically distinct forms of this enzyme as many visitors to hair-loss web sites are aware of. These chemically distinct forms are called isoenzymes. Both of these isoenzymes, type I and type II, catalyze the same physiological reaction, namely, the conversion of testosterone into DHT.
Many dermatologists and research scientists specializing in hair loss believe DHT molecules may diffuse into the interior of hair follicle cells (the cytoplasm or cytosol) and bind with androgen receptors. This complex, both the receptor and the DHT molecule, then enters the nucleus of the cell. In the nucleus of the hair follicle cell this complex could then alter the rate of protein synthesis in men who are genetically predisposed to baldness.
The FDA-approved drug Propecia (finasteride, active agent) inhibits type II 5-alpha reductase; the drug Avodart (dutasteride, active ingredient) inhibits both type I and type II 5-alpha reductase. (Avodart is approved by the FDA only for benign prostatic hyperplasia (BPH).)
The consequent lowering of DHT in scalp tissue by these drugs stabilizes hair loss and even promotes the growth of healthy terminal hair in the crown area of an estimated 35 percent of men who use these drugs. Younger men whose hair loss is not yet severe may respond better than men who have been bald for many years. There is some statistical evidence, though, that older men may respond just as well as young men.
When I was 19 years old and losing some hair, I probably would have used either Propecia or Avodart if they were available. I think young people who are desperate because of hair loss will do just about anything to combat it without too much concern about possible long-term consequences. I said possible long-term consequences because no one knows as yet what these consequences, if any, may be.
There definitely are short-term consequences for some men taking 5-alpha reductase inhibitors though. Merck says that for Propecia these short-term side effects are experienced by less than one percent of users. (If you read the messages on the hair-loss forums, you’ll think it’s much higher.) Some professionals speculate that the potential for side effects with Avodart will be at least twice as high as those with Propecia. This is because both isoenzymes are inhibited with this drug.
These side effects are: impotence (you can’t get an erection or keep one), decreased sexual desire or drive, decreased volume of semen, and a less satisfying orgasm. If a person experiences these side effects, all he has to do is quit taking the drug. In a few weeks the side effects should disappear.
Things To Consider
DHT should not be demonized in the thinking of men concerned with hair loss. It is definitely a misconception to believe that all that DHT does is cause your prostate to swell up or your hair to fall out. DHT does much more than that. DHT plays an important role in the functioning of the central nervous system (the brain), the testicles and prostate, and almost everything but muscle tissue. In muscle tissue testosterone is the dominant hormone. (Some bodybuilders inject testosterone derivatives to gain muscle fast.)
When a man decides on a lifetime commitment to a 5-alpha reductase inhibitor like Propecia or Avodart, he should consider several factors besides the possible stabilizing of hair loss. And, by the way, a lifetime commitment is recommended because if you stop using the drugs, all that was gained will be lost in a matter of months.
1. Propecia and Avodart cause a rise in testosterone levels. Since these drugs inhibit the enzyme 5-alpha reductase, the testosterone that would normally be converted into DHT by this enzyme is not so converted. Continual high levels of testosterone in the body could possibly have negative side effects.
2. Artificially low levels of DHT in the body could cause some unwanted conditions. DHT is an antagonist of estrogen. Men’s bodies also produce the female hormone estrogen in the adrenal glands although this is just one-tenth of the estrogen that premenopausal women produce in their ovaries. By reducing DHT with drugs a man’s protection from the effects of estrogen may also be reduced. Gynecomastia could be one result of this. Gynecomastia is abnormally large breasts in a male.
3. Even though both finasteride and dutasteride were developed to combat benign prostatic hyperplasic (BPH) by reducing DHT in prostate tissue, some scientists question the wisdom of using these 5-alpha reductase inhibitors in younger men who have no problem with their prostates.
This quotation is from a research chemist, Pat Arnold - “Evidence is mounting that the existence of a high estrogen/androgen ratio - a condition common in older men - is highly correlated with the development of BPH.”
An FDA-approved systemic drug like Propecia has helped many men to combat hair loss, especially in the crown area. It does this by altering certain hormone levels in the body. I hope people who are experiencing hair loss will do some intensive reading before committing to the lifetime use of this drug though. Taking Propecia is not like taking a vitamin pill. It’s a serious decision that should be based on a careful study of some of the excellent literature out there on various hair-loss web sites and discussion forums.