How do goosebumps affect hair loss?

Could goosebumps be a cure for baldness? The development of hair growth treatments has always been an important topic in regenerative medicine. The dermatology research team at the National Taiwan University Hospital collaborated with researchers at Harvard University to unveil the secrets of hair growth. They found that the arrector pili muscle contracts to produce goosebumps when experiencing cold or frightening situations. This enhances the activity of hair follicle stem cells and promotes hair regeneration. Together, the muscle and the sympathetic neurons form a synapse-like structure that regulate the activity of the hair follicle stem cells.

In human evolution, the protective mechanism of vertical hairs was replaced by “goosebumps”. When the sympathetic neuron is highly activated, it causes the arrector pili muscle to contract and produce goosebumps. It also enhances hair follicle stem cell activity, resulting in hair regeneration. The stimulation of sympathetic nerves reduces the dormancy of the arrector pili muscle and allows better activation of follicle stem cells. Moreover, the sympathetic nerve will retreat from the area surrounding the follicle if there isn’t support from the arrector pili muscle, entering the stem cells into a deep dormancy period and stopping any hair growth.

There are many different causes of baldness, but they can be roughly divided into three categories: hairs stopping in the anagen phase, hair follicle stem cells entering dormancy and staying in the telogen phase, and complete hair follicle miniaturization causing difficulties in regeneration. The research team mainly targeted the second category, invigorating the stem cells through the above mentioned mechanisms and attempting to help the hair grow back. The scientists found the disappearance of the arrector pili muscles in the scalp of patients with male-pattern baldness, indicating a lack of sympathetic nerves in the pathogenesis of androgenetic alopecia.

So can being frightened help promote hair growth?

This study noted that it would likely elevate health risks if the sympathetic nerve is fully activated. At present, the research team has conducted animal experiments that have successfully activated the hair follicles of experimental mice and cultured human hair follicle stem cells. New hair growth promoting drugs that stimulate hair follicle stem cells and help hair growth by direct smearing of product on the scalp may be launched in the near future.

 

REFERENCE: Cell. 2020 Aug 6;182(3):578-593.e19. doi: 10.1016/j.cell.2020.06.031.