Have you ever noticed how bald men’s scalps often look shiny? How the skin appears harder and more tight compared to skin elsewhere on the body? It’s not a coincidence. In fact, these characteristics provide valuable insights into the causes of pattern hair loss. Most importantly, though, they could provide the key to reversing androgenetic alopecia and regrowing a full head of hair.
The current explanation of pattern hair loss
If you ask your doctor about pattern hair loss, chances are he’ll tell you that a hormone called dihydrotestosterone (DHT) binds to hair follicles, causing them to shrink and eventually stop producing hair.
This explanation is based on various observations made in the 20th century. For example:
- Men with a genetic deficiency of DHT never go bald.
- Proscar and Propecia, two drugs that lower DHT levels, slow the progression of pattern hair loss.
- DHT also explains why pattern hair loss tends to affect women more than men – women generally have far lower levels of this hormone.
These observations make it clear that there is indeed a link between DHT and hair loss.
However, the hair-miniaturising effects of DHT have never actually been observed in practice. Not only that, there are a number of problems with this simple explanation:
- DHT causes hair growth elsewhere on the body
- Men can have high levels of DHT but never go bald
- Bald men are more likely to suffer a number of seemingly unrelated conditions – heart disease, prostate cancer, insulin resistance
- There are various other differences between bald scalps and non-bald scalps besides DHT
This last point is the focus of this article, and we’ll get to that in a minute. For now, though, the evidence is pretty strong to suggest that DHT is only part of the story.
For a more detailed look at the links between DHT and hair loss, check out this article.
Bald scalps vs. non-bald scalps
Besides elevated DHT levels, there are a number of differences between bald and non-bald scalps.
A finding that has caused a great deal of interest in recent years was the observation that PGD2 levels are around 3x higher in bald men’s scalps compared to non-bald men. This has since spawned a number of attempts to develop a hair loss cure that works by reducing PGD2.
Another observation that gets less attention than it perhaps deserves is that bald scalps have significantly reduced blood flow.
And finally, the difference that we’ll focus on in this article is that bald scalps have significantly increased collagen bundles compared to controls. This observation goes a long way to explaining the problems with the DHT hypothesis explained above, and may well provide the key to actually reversing pattern hair loss.
Collagen is the main structural protein of the body’s skin and connective tissue. Your body produces collagen to heal cuts, grazes, etc. but sometimes too much collagen is produced, leaving scar tissue.
An excess of collagen, such as is produced when a cut is particularly deep, is called fibrosis.
Fibrosis doesn’t just occur in response to injury though. It can occur in any tissue of the body, such as the lungs, the liver, or the heart (more on this later).
Scleroderma is an autoimmune disorder that leads to fibrosis of the skin. This excess collagen produces hard, tight skin that can often look shiny – not massively dissimilar to the appearance of the scalp in advanced (Norwood 7) pattern hair loss (thanks to Rob from Perfect Hair Health for pointing out the similarities between these two conditions).
Hair loss and fibrosis
So, are the visual similarities between scleroderma (fibrosis) and pattern hair loss just coincidental?
This study suggests not. Collagen levels in bald scalps were measured and compared to control (non-bald) scalps. The result:
“It was found that collagen bundles were significantly increased in balding vertexes than in non-balding occiput scalp skin. A near 4-fold increase in elastic fibers was observed in both vertex and occiput scalp skins with MPHL versus controls.”
The link is further strengthened by the observation that PGD2 stimulates calcification and fibrosis. As mentioned above, PGD2 levels are around 3x higher in bald scalps.
This all raises the question of whether this fibrosis causes hair loss, or whether it is merely correlated with it.
Unfortunately, there are no studies that have specifically addressed this question. However, findings from related studies suggest the link between hair loss and fibrosis is causal, not merely correlative.
This study describes a rare case of scleroderma (fibrosis) of the scalp. The subject, a female, experienced hair loss precisely in the area of fibrosis, but not anywhere else on the scalp.
This strongly suggests that fibrosis causes hair loss.
Further, the fact that the subject was female significantly reduces the likelihood of DHT being to blame. It seems that calcification and fibrosis cause hair loss even in the absence of androgens.
So where does DHT come into the picture?
At present, we have two competing explanations of pattern hair loss: fibrosis and DHT.
The current medical consensus is that DHT binds to hair follicles, causing them to shrink and stop producing hair. In other words, that DHT causes hair loss. This is what most doctors will tell you.
But this causal relationship between DHT and hair loss has never been properly established. And there are a number of problems with this explanation, as we saw earlier.
Given that fibrosis is elevated in pattern hair loss, and fibrosis causes hair loss even in the absence of DHT, it seems more reasonable to argue that fibrosis is what causes hair loss, not DHT.
So where does DHT fit in this picture? After all, drugs that reduce DHT have been demonstrated to be effective at slowing down pattern hair loss – it must have some effect on hair loss.
And it does. But it seems more likely that DHT is in some way linked to fibrosis, which in turn causes hair loss.
If true, this would explain why men with pattern hair loss are more likely to suffer from heart disease: heart disease is strongly linked to fibrosis. The fibrosis explanation also explains why Propecia and other drugs that reduce DHT levels rarely regrow hair: they don’t reverse the fibrosis, they just prevent it from getting worse.
Whatever the relationship between DHT, fibrosis, and hair loss, the links between them shouldn’t be ignored. And given the common link to heart disease, the issue is likely to be more than simply cosmetic.