DHT is certainly a factor in the equation.
But here’s the problem…
The problem with this answer is it doesn’t explain why some people have high DHT levels and still lose their hair.
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Take for example the actor Alec Baldwin. You can see he has the characteristics of high DHT levels — very thick body hair growth and thick facial hair, but he has never lost the hair on his head.
DHT is what makes a man grow a beard. It also causes body hair growth. So if a man has thick facial and body hair, it’s very likely he has high DHT levels — like Alec Baldwin.
So why do some people have high DHT but don’t lose their hair?
It’s at this point most people say “hair loss is caused by DHT, but only affects people whose scalp hair follicles are sensitive to DHT“.
So you have to ask yourself, why are some people’s hair follicles more sensitive to DHT?
Because that’s the real question isn’t it?
Technically, DHT alone cannot be the cause of hair loss. Yes there is a correlation between high DHT and high rates of hair loss, but it isn’t necessarily a direct causal correlation. Why? Because some people have high DHT but don’t lose their hair.
So the question we have to ask is, why do some men have hair follicles in their scalps that are more susceptible to the effects of DHT?
If you understand this, you will understand what the true cause of male pattern hair loss is.
There are several half-decent theories on this, but here’s my opinion:
Certain, very specific types of stress cause inflammation:
According to one study, stress associated with social rejection can lead to inflammation.
Central to this social signal transduction theory of depression is the hypothesis that experiences of social threat and adversity up-regulate components of the immune system involved in inflammation.
From Stress to Inflammation and Major Depressive Disorder: A Social Signal Transduction Theory of Depression
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It’s widely believed by many hair loss researchers that the thing that kills off your hair, in the end, is fibrosis of the hair follicles.
This is basically scarring caused by inflammation in the hair follicles. The hair follicles become destroyed by inflammation and scarring, which prevents them from growing.
The current model of AGA suggests that ‘micro-inflammation’ in AGA might trigger apoptosis and perifollicular fibrosis which in turn causes hairs to miniaturize and shed.
Dr Jeff Donovan
More from Donovan on micro-inflammation and follicular fibrosis:
Ramos in 2016 showed that inflammation is more common around miniaturizing hairs and this inflammation seems to be associated with a form of cell death known as apoptosis.
Now, it’s plausible that men with both high DHT and high-stress levels during their late teens and early twenties experience extremely high levels of micro-inflammation in their scalps, which leads to perifollicular fibrosis, which causes the familiar V shape receding hairline of male pattern hair loss.
We also know that subcutaneous fat reduces in the scalp as men age — much more so in men than women. And this seems to correlate strongly with hair loss:
The thickness of the dermis, hypodermis and galea capitis of the scalp skin varied with gender and age of subject. The thickness of the epidermis, dermis and hypodermis in a balding subject was significantly decreased by comparison with those in a normal subject.
(Hori H, Moretti G, Rebora A, Crovato F. The thickness of human scalp: normal and bald. J Invest Dermatol. 1972 June; 58(6):396-9)
The enhancement of subcutaneous fat in areas associated with increased hair growth is highly significant. Male pattern baldness is intimately associated with a dramatic reduction in the amount of subcutaneous fat associated with hair follicles that are nonproductive. Conversely, during periods of rapid hair growth in mammals, the subcutaneous fat content increase two-to-threefold.
Subcutaneous Fat (good fat under the skin, stores energy)
It’s possible that this has a restrictive effect on blood circulation in the scalp. This may contribute to hair follicle miniaturization.
Why do men lose the subcutaneous fat in their scalps, while women don’t until they reach menopause?
This could have evolved as a way for women to store a reserve of energy in the form of fat so they have extra energy in the event of pregnancy.
Women at some point in their lives may nourish a fetus and then a baby from their own reserves, so women have to stock energy in the form of fat in anticipation of future pregnancies
The clues seem to strongly point towards loss of subcutaneous fat as being a cause of male pattern baldness. So much so that some hair loss experts believe this is the one true cause:
In a PRS Open Journal paper, Dr. Emin Tuncay Ustuner cites the “force of downward pull caused by the gravity on the scalp skin” as the primary cause of male pattern baldness.
Ustener points out that loss of subcutaneous fat in the scalp would result in increased pressure at the top of the head but not the back and sides — which of course is where male pattern hair loss occurs — usually the hair on the back and sides of the scalp is not lost.
However, it’s possible that the correlation is not causal. It’s tempting when a correlation is observed to conclude that its a causal correlation, but it might not be the case.
A study published in 1998 ascertained the following:
Balding cells contained significantly (P 0.01) greater levels of androgen receptors (Bmax = 0.06 +/- 0.01 fmol/10(4) cells (mean +/- S.E.M.)) than those from non-balding scalp (0.04 +/- 0.001) Hibberts NA1, Howell AE, Randall VA.
Here we see another correlation: bald men have more androgen receptors in their scalp hair follicles. This strongly supports the theory that the action of DHT binding to receptors in scalp hair follicles causes hair loss in the scalp.
But wait, there’s a problem
DHT binding to androgen receptors in hair follicles is actually what makes the hairs grow thicker and longer everywhere else on the body. The scalp is the only place where DHT has the reverse effect. In the beard hairs, chest hairs, arm hairs and everywhere else, DHT binds to receptors in the hair follicles, making them grow longer and thicker.
So why does DHT have the reverse effect in the scalp?
Well there is at least one theory on this — which brings us back to subcutaneous fat. But I’ll have to leave that for another day as I’ve run out of time. If you’d like to read the rest of this article, please leave a comment, to remind me to finish it!