Stress hormone found to cause hair loss, new study finds

Could reducing stress be the secret to hair growth?

According to a new study led by Seyku Choi, of Harem University’s Department of Stem Cell and Regenerative Biology, this may just be the case.

Generally, a person has three phases of hair growth cycle: growth, degeneration and rest. In the first phase, the hair is a constantly extruded shaft, while the hair stops growing and its lower part shrinks while remaining in the second phase. In the third stage, however, the hair eventually falls out.

Although it has been known for some time that stress is linked to hair prematurely entering and falling out of the third stage, as well as the overall link between hair loss and chronic stress itself, the exact mechanism behind this link has remained a mystery.

What is known is that hair follicle stem cells (HFSCs) play a significant role in hair growth by interpreting internal and external signals. Knowing that Cho and the other researchers tested the role of another part of the body, specifically the uterus that produces the hormone that is played in the cycle. To do this, they removed them through surgery of mice.

Without the adrenal glands to produce stress hormones, the mice’s ‘resting’ phase in their hair cycles was much shorter, while their hair follicles grew about three times more than normal. But when the hormone corticosterone, the stress hormone fed by animal adrenal glands, is fed, their hair is suppressed.

So does corticosterone play a role in making hair fall out? This is what it implies. HFSCs detect the stress hormone through signals and not by detecting the hormone itself. This was determined when the researchers removed the protein, known as glucocorticoid receptors, in the intestinal papillae. These receptors are the way the hormone indicates the HFSCs.

But how do the intestinal papillae transmit the signal? According to the study, this is done by another protein, the growth stop-specific 6 (GAS6). Through this protein, the signal is sent to the HFSCs by another protein, the AXL receptor.

These findings, published in the academic journal Nature, essentially maps the process by which stress affects hair loss, and can pave the way for the treatment of stress-induced hair loss.
In addition, the findings also come in the wake of the COVID-19 pandemic, which has caused significant strain on the world population as the fight against the disease rages.

However, the study warns that several issues need to be investigated even further. For example, corticosterone is not the human stress hormone, but is only considered as the rodent that is equivalent to human cortisol. As such, it is not known whether the process is exactly the same. Second, the phases of the hair cycle have different durations among humans, so it is unclear whether the hormones affect it in the same way. Third, the GAS6 protein is not just limited to this particular signal. The researchers found that it was involved in the expression of various genes involved in the HFSCs. As such, tampering with it can have other unintended consequences. There is particular fear that this may unknowingly lead to the growth of potentially mutation-causing HFSCs.

It should also be noted that there are different types of hair loss associated with stress. According to the Mayo Clinic, telogen is effluvium, which sees the hair being pushed into the resting phase, leading to significant hair loss. The other two differ, however.

One of these, known as Trichotillomania, is the condition when tension, frustration and other negative emotions form an irresistible compulsion to pull your hair out, the literal definition of ‘pulling your hair out’.

The third form is very different. Alopecia areata, known as alopecia areata, is an autoimmune disorder and can cause hair loss due to the immune system of the body attacking the hair follicles. There are a number of possible causes of this condition, with high stress one being one, although the condition itself is also known to be a cause of significant psychological stress.

The findings in the study nevertheless found valuable links between stress and hair loss, and this may pave the way for future studies that may further investigate these links.

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