Before we go into the skin whitening solution, we should first understand how pigment is formed.
How does skin darken?
Skin tanning is actually a protective mechanism from the ultraviolet exposure. Sunburn can be caused by excessively exposure to UVB, which have short wavelength but high energy. UVA, which has lower energy but a longer wavelength, can penetrate deeper into the dermis and damage skin DNA. Melanin is a protective layer that filters UV rays to protect the skin.
However, in addition to UV rays, emotions, stress and endocrine disorders can affect the production of melanin.
When skin is exposed to UV rays for a long time, under the influence of emotions or stress, etc., keratinocytes will release active free radicals. This stimulates peripheral nerves to release cytokines, causing inflammation and promoting the secretion of alpha-melanocyte-stimulating-hormone (α -MSH) by the pituitary gland. Tyrosinase is then activated and synthesizes tyrosine in melanosome into DOPA before it is further converted into "pheomelanin" or "eumelanin", collectively known as melanin.
After melanosome leaves melanocytes, it then is phagocytized (“eaten”) by keratinocytes and slowly moves towards upper part of the skin to become part of the stratum corneum. The skin darkens and dark spots will be formed if the melanin accumulates on the spots.
Research shows that extensive exposure to blue light will also have similar skin damage as exposure to UVA. It can also cause long-lasting pigmentation.
After we understand the mechanism of melanin formation, we can go onto the solution to be discussed in part 2. Stay tuned.