It seems that every year a new theory as to what causes hair loss is announced by researchers.
But there is one theory that isn’t given as much credit as it may deserve, and that’s the scalp tension model of hair loss.
In this post, we’ll discuss the current hair loss model. This will include a look at some research on the topic.
We’ll then introduce the scalp tension theory and outline the latest studies performed to date.
Finally, we’ll outline a few ways you may be able to combat tension-induced hair loss.
Let’s get started!
The Current Hair Loss Model
There are plenty of theories that aim to summarize the cause of pattern hair loss, though there is one theory that many scientists and doctors have come to embrace.
But to understand the theory, you first need to understand some key terms.
The name Androgenetic Alopecia (AGA), the medical jargon for male-pattern baldness, is actually a very descriptive term for the condition itself.
When broken down, the name includes the components Andro (androgens), genetic (genetics), and alopecia (hair loss).
The believed cause of AGA, then, is quite clear: a combination of androgen hormones and genetics.
There’s a lot of evidence to back up these claims, especially as it relates to androgens.
The androgen hormone DHT is believed to play a large role in the pathogenesis of pattern hair loss.
In fact, balding scalps have been shown to have higher androgen activity than non-balding scalps (1). And, unsurprisingly, they also show higher levels of inflammation (2).
The follicles of balding men have also been shown to have greater androgen sensitivity which is largely believed to be caused by genetic factors (3).
Unfortunately, the exact genes which contribute to AGA haven’t been pinpointed.
As one scientist states, “We probably deal with a polygenic inheritance dependent on a combination of mutations, e.g. in or around the AR (androgen receptor) gene affecting the expression of the AR, and other genes controlling androgen levels (4).”
But no matter the cause of this sensitivity, the main basis of this theory is clear: androgen sensitivity leads to inflammation and miniaturization of the hair follicles.
To make matters worse, the presence of DHT may also contribute to the formation of scar tissue. This was highlighted most effectively in a 2008 study which showed that the scalps of balding men have four times the amount of excess collagen deposition than the scalps of their non-balding counterparts (5).
If we consider the current theory, then, the path would look something like this:
- DHT attaches to the androgen receptors found on the follicle.
- This interaction within DHT-sensitive follicles causes inflammation.
- The inflammation causes long-term blood restriction which leads to miniaturization of the follicle.
- The scalp will soon take on the classic pattern of balding and, if left untreated, the skin will calcify and new hair growth will be impossible.
There is new research, however, which suggests that this current understanding isn’t as accurate as we once believed.
The Problems With the Current Model
We say the current model of hair loss, but what we really mean is the hair loss model which has been tweaked and studied for centuries.
There’s no doubt that there are some things that the current model gets right. But there are other aspects that lead to more questions. The majority of these questions surround DHT and the role it actually plays in hair loss.
But perhaps the greatest question surrounding DHT and AGA is, how exactly does DHT lead to increased inflammation?
After all, research has shown the anti-inflammatory effect of androgen receptor activation in human cells (6).
The answer?
Well the high levels of DHT may not be the cause of the inflammation. Instead, the scalp tension theory postulates that the increased DHT levels are in response to inflammation.
And where does this inflammation come from if not DHT itself? Scalp tension.
The effects of inflammation on androgen activity have been studied since at least the 1990s (7, 8). One thing that the majority of these studies have in common is that androgen activity is induced as a way to decrease inflammation.
Does this mean that the current model of AGA needs to be thrown out entirely? Not at all!
It does, however, need to be refined so as to include the latest discoveries on the subject.
What Is the Scalp Tension Theory?
To understand the scalp tension theory, it first helps to understand the structure of the human scalp.
There are five layers of the scalp, which from outermost to innermost include the 1) skin; 2) subcutaneous; 3) galea; 4) subgalea; and 5) pericranium (9).
When it comes to scalp tension, though, we’ll focus largely on the galea.
The galea is a fibrous tissue that covers the entire scalp. It extends from the frontalis muscle which is just above the eyebrow to the occipitalis muscle which is behind the ears.
As the galea makes up such a large portion of the scalp’s connective tissues, it makes sense that mechanical stress (or tension) would affect it greatly.
So, what does the scalp tension theory have to say about hair thinning and loss? And how does it add to our current understanding on the topic?
The basics of the theory suggest that scalp tension causes chronic inflammation which eventually leads to restricted blood flow and follicle miniaturization.
The theory goes on to state that “this model … refutes the belief that AGA-prone follicles are genetically programmed to become sensitive to DHT (10).”
What exactly does this mean?
The main theory of pattern baldness suggests that the androgen hormone DHT is the main cause of thinning and hair loss.
The scalp tension theory denies this claim, and it also goes on to modify it.
Do you remember the four-step pathway above?
Here it is again, but with some additions and a few adjustments (in bold):
- Chronic tension within the galea triggers inflammation.
- The body responds by recruiting anti-inflammatories to the site of inflammation, including DHT.
- DHT attaches to the ARs found on the follicles, and the higher levels of inflammation the higher the levels of DHT.
- The presence of DHT leads to the arrival of transforming growth factor beta 1 (or TGFβ-1), a signaling protein which is a known precursor to fibrosis (11).
- With the tension left untreated, and the presence of TGFβ-1, the inflammation continues even in the presence of anti-inflammatory agents. This causes long-term blood restriction which leads to miniaturization of the follicle.
- The scalp will soon take on the classic pattern of balding and, if left untreated, the skin will calcify and new hair growth will be impossible.
These claims are further backed by the fact that mechanical tension has been shown to increase activity of the androgen receptor co-activator Hic-5.
This co-activator stimulates the normally functioning androgen receptors and may make them more susceptible to sensitivity.
Prior to the scalp tension theory, there was no known reason for the sensitivity of the ARs except genetics. This theory, though, offers up another pathogenesis for the condition.
The Scalp Tension Theory: The Scientific Evidence
Aside from the 2015 study discussed above, there have been other studies to support the scalp tension theory.
One such study was published in 2017 by researchers in India (12).
It’s known that injection of botulinum toxin, more commonly known as Botox, relaxes muscles. As a result, the injection can increase blood flow to the area.
But what researchers wanted to know was whether botox could have the same effect on the scalps of balding men. And if so, what the effects would be on hair growth.
To answer these questions, the researchers recruited ten men between the ages of 22 and 42 with AGA.
The men received a total of 150 U of botulinum toxin A distributed throughout 30 different sites on the scalp.
The injections were intramuscular, and they were given in the frontalis, occipitalis, temporalis, and periauricular muscles.
Prior to treatment, the men’s scalps were photographed and examined. The photographs were repeated at 24 weeks, and these were the results:
Out of 10 patients, 8 (or 80 percent) had “good to excellent response” based on photographic evaluation. Of the two men who did not rank as good or excellent, one result was poor and the other was fair.
As stated by the researchers, “Injection of botulinum toxin relaxes the muscle, which reduces pressure on the musculocutaneous and perforating vasculature, thereby potentially increasing the blood supply and transcutaneous pO2.”
These findings strongly support the scalp tension theory of hair loss.
Of course, larger studies are needed to gain a better understanding of the results and mechanisms.
How to Combat Tension-Induced Hair Loss
If tension is to blame, then how can you combat it?
The answer is scalp stimulation.
As mentioned above, the tension which triggers hair loss will also induce fibrosis of the scalp tissues. This is the formation of excess fibrous tissues which hardens the scalp and makes regrowth impossible.
You can combat fibrosis in its earliest stages, though.
How? By increasing blood flow and breaking up the fibrous tissues.
Scalp Massage
One of the most popular hair loss treatments on the market, Propecia (finasteride), aims to lower DHT level by inhibiting the enzyme 5AR.
And while this is helpful to an extent, a decrease in DHT levels isn’t often enough to recover hair loss.
That’s not to say that drugs like finasteride don’t stop hair loss. But they do very little to reverse it.
This is where methods like scalp massage can come in handy.
Scalp massage is manual stimulation of the scalp, either using your hands or a specialized tool.
The goal is to increase blood flow to the immediate area while also loosening the tissues so as to reverse and prevent fibrosis.
But just how effective is a procedure as simple as scalp massage at reversing hair loss?
One study showed that within just 24 weeks the practice increased hair thickness and resulted in significant changes in gene expression (13).
So, how can you reap these benefits at home?
By Hand
The easiest way to perform a scalp massage is with your hands.
To start, place your thumbs, middle fingers, and index fingers on either side of the head just above the ears. Begin to use a slow, circular motion.
Make your way up the side of your scalp to the crown. Continue the circular motions, and retrace any areas you think you may have neglected.
Next move from the crown to the temples and be sure to focus on any areas with noticeable recession.
You’ll then move to the forehead, back to the sides of the head, and then to the base of the skull.
For best results practice this technique once per day for at least ten minutes.
With a Massage Tool
While a scalp massage with your hands can be beneficial, a specialized massage tool can sometimes help you to be more thorough.
The massage tool is usually made of metal, though sometimes plastic, and it resembles an unconnected egg beater with small pieces of plastic on each tip.
You just have to place the tips on the crown, and then slowly move the tool up and down to reach all areas of the scalp.
Microneedling
If you want to take your efforts one step further, then you may want to consider microneedling.
Microneedling, also known as Collagen Induction Therapy (CIT) and dermarolling, is a cosmetic procedure that uses tiny needles to penetrate the skin and wound the tissues.
But how can intentionally wounding yourself lead to increased blood flow and possibly hair growth?
Through the power of the wound healing process!
The superficial wounds on the skin will go through the various stages of wound healing, which include remodeling of the tissues and proliferation of new skin cells (14).
And as it relates to hair growth, the process has even been shown to “recruit growth factors and signaling pathways which induce hair restoration (15).”
As you might imagine, this technique is more intense than scalp massage. However, it can easily be practiced at home in just twenty minutes per week.
All you need is a microneedling tool, such as a dermaroller or a dermastamp.
You then apply the tool to your scalp, either gently rolling (dermaroller) or pressing (dermastamp) in areas with noticeable thinning and hair loss.
You can repeat the process once or twice per week, and you may even see results in as little as 12 weeks (16)!
Botox Injections
Since the research has been outlined above, I won’t go into too much further explanation.
And while botox injections may not be a conventional treatment for hair loss at this time, they may become one that’s offered not too far into the future.
The fact of the matter is, botox relaxes muscles. And if scalp tension is the cause (or at least a contributing factor) of hair loss, it makes sense that this popular cosmetic procedure would be adopted by hair loss sufferers worldwide.
If you do choose this route, there are a few things to keep in mind.
Most importantly, you should only ever receive botox injections from a trained medical professional.
As the name implies, botulinum toxin is, well, a toxin. If administered incorrectly, it can lead to permanent damage and even death.
When administered in a medical environment, however, the risks are minimal.
Mechanical Offloading
Using a mechanical device which inflates an inner tube to help push the scalp upwards has also shown promise at reducing scalp tension.
We take a deeper look at these devices, primarily the growband here.
The downside is that these kind of things require daily use to be really effective, so you’ll be looking at about 10 minutes per day of use, but for many people this will be worth it.
Conclusion
Androgenetic alopecia, also known as pattern baldness, is a complex condition. There are many factors which likely contribute to its progression, including genetics, androgens, and even tension.
But the real question is, does the scalp tension theory of hair loss do a better job of explaining the condition than our current understanding?
There’s no doubt that the tension theory offers new insights and it even answers a lot of questions. But there are still many questions that need answering before we can declare it the superior model of hair loss pathogenesis.
In the meantime, it’s comforting to know that research on hair loss and its causes is ongoing.
Do you have questions about the scalp tension theory as it’s presented above? Please leave a comment below.
