Science and technology is anything but stagnant, new developments and innovations are constantly being created. I’m sure most of you reading this have heard of the newest iPhone, electric car, etc., but there are still many areas that have remained relatively unchanged in the last decade, and hair loss is one of them.
When it comes to hair loss, not only do we not have a full-proof treatment, but scientists are still not even completely sure what the primary cause of male/female androgenic alopecia (AGA; pattern hair loss) is. But, with each new year comes new information, technology, treatments, and more.
In this article we are going to discuss, as of March 2021, what the most up to date information can provide us in terms of what the primary cause of male/female pattern hair loss is.
Causes of pattern hair loss in 2021
Originally, hair loss was believed to be caused solely by dihydrotestosterone (DHT).
Scientists understand that the enzyme 5-alpha reductase (5-AR) catalyzes a reaction that causes testosterone to form into DHT, to which the DHT binds to receptors located in the hair follicles.
For people who are genetically predisposed to hair loss, when DHT binds to the receptors it causes the process of miniaturization to occur.
Miniaturization: the shortening of the growth phase of the hair cycle.
The hair growth cycle consists of four phases: the anagen (growth), catagen (transition), telogen (resting), and exogen (shedding). As miniaturization occurs, the anagen phase begins to shorten, and each cycle it becomes shorter and shorter. Eventually it gets so short that the hair no longer penetrates the scalp, meaning that the hair follicle is considered “dead” and can no longer be revitalized by treatments. This is what causes balding.
As of 2021 we know that miniaturization is what causes hair loss, but what we do not know is what causes miniaturization. Again, the original line of thought was that DHT is the only cause of miniaturization, but research has revealed that blocking DHT may not be the end all be all for overcoming hair loss.
Blood flow and hair loss
Blood flow and hair loss are inherently related. This is because blood supplies hair follicles with nutrients and oxygen that it uses to grow, and when there is low blood flow there is subsequently not enough vital compounds supplied to the hair that results in hindered growth.
Traditionally it was thought that low blood flow was the result of DHT causing miniaturization, but it may actually be the cause of miniaturization. Let’s dive into it.
Originally, studies showed that hair follicles stop growing before the capillary networks begin to lose function (i.e. blood flow slows down) (1) (2). In essence, what the researchers found was that changes in the catagen hair caused it to stop growing (i.e. miniaturizing), to which blood flow began to lessen after these changes occurred, leading them to believe that the low blood flow wasn’t causing the hair to stop growing.
This evidence is what many people turn to when determining the cause of hair loss, allowing them to “rule out” blood flow as a potential cause. But there is contradictory evidence that shows blood flow could be the culprit after all.
It all has to do with your scalp.
The galea is a sheet of fibrous tissue that connects the muscles of the front and back of the scalp to the neck muscles and its main function is to provide mobility and protection for the scalp.
Located just under the galea, and coincidentally in the areas where hair loss typically occurs, is a layer of blood vessels that are connected to your hair follicles. The theory is that factors such as poor posture (which stretches the galea) and/or a thicker galea can cause these blood vessels to compress. This means that less blood flow is supplied to the follicles, but does that mean it causes hair loss?
One such study wanted to put this to the test (5). Researchers injected botox into the scalps of a group of men that were affected by AGA. The botox was meant to help relax the scalp and neck muscles to (theoretically at the time) release tension in the galea. The results were astonishing.
There was a 75% response rate in the treatment group that had an average 18% increase in hair count after a year, and this is not the only study that has shown results like this, other studies have been able to repeat it (6) (7).
What the findings of these studies strongly suggest is that by relaxing muscles in the scalp and neck, and thus improving blood flow, hair regrowth is possible (and maybe even probable). But beyond that, they also showed that low blood flow and miniaturization doesn’t always happen as a result of changing catagen hairs, but can occur due to other factors such as scalp tension.
Ergo, because pattern hair loss is caused by miniaturization, this means that low blood flow (due to scalp tension, but possibly other factors as well) can potentially be a cause of it.
Contrary to initial findings and the traditional narrative, DHT may not be the only cause of hair loss.
We know that miniaturization is the cause of hair loss, and as more information has become available we now know that both blood flow and DHT may contribute to it. Does this mean that either DHT or blood flow is the cause of hair loss for certain? No, but as of 2021 the information we have available supports both DHT and blood flow as a potential cause of hair loss.
Use treatments that target both blood flow and DHT if you want to overcome hair loss. Leave no stone unturned.