DHT and Male Pattern Baldness

It’s commonly accepted that the substance Dihydrotestosterone (DHT) is a major factor in androgenic alopecia (AGA), that’s male pattern hair loss to you and me. DHT is the most potent of all androgens (male sex hormones) which affects the hair growth cycle. Androgens are the driving forces in our body that determines hair distribution, including the hair on the scalp. The current theory is that DHT binds to the hair follicles, it then enters cells preventing ribonucleic acid (RNA) polymerase from functioning, RNA is key to protein synthesis. It plain English, this means if hair cells cannot create protein then hair will not grow and eventually will die.

If you want proof that androgens are involved in hair loss then you can look back through history at men who have be castrated (ouch), which is where the bollocks, sorry, I mean testicles, are removed (ouch again!). This means their body can no longer produce testosterone. These people never go bald from AGA, however when castrated males are injected with testosterone they become susceptible to baldness again. From this it is clear to conclude that testosterone plays a key role in AGA. This is probably also why women commonly don’t suffer from this type of baldness, having much lower levels of testosterone in their body.

DHT doesn’t just appear magically in the body, it occurs as the result of biological process. An enzyme called 5-alpha-reductase (5AR) converts testosterone into DHT. Testosterone is a hormone that circulates in the body and into cells, including hair follicle cells. Testosterone can also be generated in the actual follicle itself. Basically: Testosterone in hair follicles + 5a-reductase = DHT = bad news! Studies confirm that men showing signs of baldness have increased activity of 5AR in their scalps. It follows, if we can stop 5AR from working we can reduce DHT levels and prevent AGA.

There are some contentious issues here as there are two types of 5AR, Type I and Type II. Nobody is 100% sure exactly how much each enzyme contributes to DHT production that leads to baldness. The Type I enzyme is commonly found in the glands in the skin in close proximity to hair follicles, Type II is found in the dermal papillae of hair follicles, both types are found in other places around the body too.

Drugs to block 5AR have been available for a while. Finasteride (sold as Propecia) blocks the type II 5-alpha reductase reducing DHT levels by up to 60% to 70%. This has seen about one in three users regrow new hair on the crown of their heads. A Type I 5AR blocker named MK386 was tested, the results showed there was no hair regrowth in the patients who undertook the trial. It would seem clear that it is the Type II enzyme which is the problem, but another drug called Dutasteride (sold as Avodart) blocks both Type I and II. What is interesting is that Dutasteride has been shown to be some way more effective than Finasteride, even despite the fact that Type I 5AR inhibition was shown to be next to useless for hair loss.

My unsubstantiated thoughts are that the total androgenic load are a significant factor that can contribute to baldness, and by using Dutasteride you reduce both forms of the enzyme reducing total levels of DHT to lower than with just Finasteride, resulting in a lower total androgenic load. Either way it still appears Type II enzyme (in the hair follicle cell) is the main culprit, with the possibility of Type I having a smaller more limited affect. Also the fact that Type I isn’t located directly in hair cells whereas Type II is may well be a factor too ie. serum DHT levels have a minimal effect on balding compared to follicular DHT.

So it’s simple, take a load of Dutasteride and Bob’s your Uncle, right? Not quite, you should be aware that the full functions of DHT are not completely understood, for example deficiency in DHT has been linked with a risk of Alzheimer’s disease and it plays important roles in the development of male characteristics such as muscle growth and keeping other hormones such as estrogen in check. There are more than likely many other useful if not vital functions of DHT – the long term implication of blocking DHT are ambiguous. Another significant factor to consider is once you start taking the drugs you will more than likely need to take them for the rest of your life if you want to keep your hair, which is far from ideal. In forthcoming articles I will look at DHT in more detail and will try to present some ideas around the topic aimed at stopping or limiting the pesky bugger.

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This article was written on November 22, 2005 was posted in these categories Hair Loss Causes .