Blue light can cause long-term tanning effects in skin particularly in Fitzpatrick types III and above, while lighter skin colors are less affected by this visible light, according to a study in the Journal of Dermatologic Science and Cosmetic Technology.
This new study explores blue light’s mechanisms of skin damage from a photobiology perspective and offers guidance for blue light protection.
Recent studies have shown that blue light exposure causes tanning in the Chinese population and that this effect is proportional to the dose of exposure. In addition, the combined effect of a small amount of Ultraviolet A (UVA) and blue light caused longer-lasting hyperpigmentation in darker skin.
The study also revealed differences in the molecular mechanisms of blue light and UVA, including their different targets of action. Blue light acts on opsin 3 (OPN3), while UVA acts on transient receptor potential ankyrin 1 (TRPA1).
Blue light produces superoxide, and UVA produces singlet oxygen. These findings further emphasize the importance of blue light protection in sun care. In terms of tanning mechanisms, blue light triggers calcium (Ca2+) flow through activation of OPN3, which in turn affects the expression of tyrosinase (TYR) and dopachrome tautomerase (DCT), ultimately leading to the release of melanosomes, resulting in skin tanning. In terms of oxidative stress, blue light-induced generation of reactive oxygen species not only damages mitochondrial DNA and affects cellular respiratory function, but also damages cellular nuclear DNA, which is closely related to inflammatory response, pigmentation, and aging process of the skin. In photoaging, blue light activates transient receptor potential vanilloid 1 (TRPV1) to generate reactive oxygen species (ROS) and Ca2+ ionic current, which promotes the expression of matrix metalloproteinase (MMP), thereby degrading collagen. Similar to UVA, blue light also reduces collagen production and accelerates skin aging by organizing the transforming growth factor-beta(TGF-β)/Smad signaling pathway.
The authors recommend a multifaceted blue light protection approach with physical and chemical sunscreens, bioprotective ingredients, antioxidants, and anti-photoaging components. MISTINE’s red rice extract is highlighted as a bioprotective example, combating ROS, melanin production, and collagen degradation caused by blue light. They note the potential use of the BL Protection Factor (PBF) in research as a standard for blue light protection.
PHOTO CAPTION: Fig. 3. Solar radiation spectrum and the ability of light to penetrate the skin
PHOTO CREDIT: Xuhui Li, et al.
