Skin whitening is the use of substances, mixtures, or physical treatments to lighten skin color, also known as “lightening”, “brightening”, “depigmentation”, and “bleaching”. Skin whitening treatments work by reducing the skin’s melanin content. Many agents have been shown to be effective in skin whitening. Some agents have beneficial side effects, including supplying antioxidants or nutrients or reducing the risk of some types of cancer. Other agents are a significant risk to health, such as mercury-based methods.
Melanin is the main substance responsible for the color of the skin. Melanin is a class of dark polymers generated by the body through the process of melanogenesis. Among the melanin pigmenting the skin and hair, two types can be distinguished based on its chemical composition and biological route of synthesis: the black and brown eumelanin and the red and yellow pheomelanin. The variation of skin color among individuals is mostly caused by variation of the content of melanin in the skin. Skin with little or no melanin is almost white. Other factors influence skin color in a lesser degree, including the amount of blood in blood vessels due to the color of blood, skin thickness, and the content of carotenoids in skin.
Skin whitening agents work by reducing the presence of melanin in the skin. To accomplish this, there are several possible mechanism of actions:
Inhibition of the activity of tyrosinase: The catalytic action of tyrosinase is inhibited by the skin whitening agent.
Inhibition of the expression or activation of tyrosinase: The antimelanogenic agent causes less tyrosinase to be generated or prevents tyrosinase from being activated to its functional form.
Scavenging of the intermediate products of melanin synthesis.
Preventing the transfer of melanosomes to keratinocytes.
Directly destroying existing melanin.
Coming soon – a directory of skin whitening resources in South Africa