Stress has been anecdotally related to a variety of changes in tissues, including hair greying. The mechanism by which stress causes hair greying has been dissected. Hair pigmentation is controlled by melanocytes, which are derived from melanocyte stem cells (MeSCs) in hair follicles. At anagen, a tiny number of MeSCs are activated and differentiated into melanocytes that migrate downward to the hair bulb and synthesize melanin which colors the newly regenerated hair. The other MeSCs remain in the stem cell niche of hair follicle and are activated in subsequent cycles. At catagen, mature melanocytes are destroyed. Moreover, under stress, the body’s sympathetic nervous system releases noradrenaline (NA), which acts directly on the β2-adrenoceptor of hair follicle bulge, causes almost all MeSCs to lose quiescence and undergo rapid proliferation followed by differentiation and migration, leading to their loss in the niche, which eventually leads to hair greying in subsequent cycles. Even so, there is still no product available to treat and prevent hair greying currently. Therefore, blocking NA action on the β2-adrenoceptor is a key to preventing melanin stem cell depletion and hair greying. β2-adrenoceptor blockers have been used for many years and are widely used to treat diseases such as hypertension and asthma, and their safety is guaranteed [11]. Propranolol is one of the most classic β2-adrenoceptor blockers, and we selected it as the positive control for subsequent operations and experiments.
Mice treated with propranolol and isoliensinine showed a significant reduction in the area of white hair on the dorsal skin. Statistical analysis result showed that propranolol and isoliensinine significantly reduced the grey hair ratios to 7.5% and 9.6%, respectively, (P < 0.05). Above-mentioned data suggested that isoliensinine effectively inhibit the stress-induced hair greying.
https://onlinelibrary.wiley.com/doi/10.1155/2023/7238029
The result showed that gray hair areas on the RTX-treated control mice was 28.5%, while with the treatment of propranolol and rhynchophylline, gray hair areas were significantly reduced to 7.5% and 8.2%, respectively. We further analyzed the single cell transcriptome data from previous studies and confirmed β2AR are dominantly expressed on melanocytes, in both mice and human skin.
As mentioned above, in our study, NA treated cells showed changes in calcium signals, cell apoptosis, and down-regulation of melanin synthesis, which were prevented after the addition of Rhynchophylline. Therefore, we proposed a hypothesis that NA affects calcium homeostasis by regulating cAMP pathway, which further leads to cell apoptosis and affects melanin production. However, the deeper connection between these pathways needs to be further explored.
So, if you’re worried about graying, you can either use topical propranolol or take it as a pill.
