Melanoidins are pigments that are formed when DHA, or dihydroxyacetone, chemically reacts with the keratin protein in the outermost layer of the skin cells. This reaction occurs when DHA is applied topically in the form of self-tanning products or when it is produced naturally in the body.
The resulting melanoidins are responsible for the darkening effect that is seen on the skin after the application of self-tanners. These pigments range in color from yellow to brown, similar to the natural melanin pigment found in the deeper layers of the skin.
Melanin is the pigment that gives color to our skin, hair, and eyes. It is produced by specialized cells called melanocytes, which are located in the basal layer of the epidermis. Melanin is responsible for protecting the skin from the harmful effects of UV radiation by absorbing and dissipating the energy from the sun.
When DHA comes into contact with the proteins in the skin cells, it undergoes a series of chemical reactions that result in the formation of melanoidins. These pigments are similar in structure to melanin and are able to absorb and scatter light, giving the skin a darker appearance.
The exact mechanism by which DHA reacts with the proteins in the skin is not fully understood, but it is believed to involve the Maillard reaction. This reaction is a complex series of chemical reactions that occur between amino acids and reducing sugars, such as DHA, at elevated temperatures.
The formation of melanoidins is a temporary effect and is not permanent. As the outermost layer of the skin naturally sheds and renews itself, the melanoidins are gradually sloughed off, resulting in the fading of the tan. This is why self-tanners need to be reapplied regularly to maintain the desired level of darkness.
It is worth noting that melanoidins do not provide any protection against UV radiation. While a tan may give the appearance of a sun-kissed glow, it does not provide the same level of protection as natural melanin produced by melanocytes. Therefore, it is still important to use sunscreen and take other sun protection measures even if you have a self-tan.
Melanoidins are pigments that are formed when DHA chemically reacts with the keratin in the skin cells. These pigments range in color from yellow to brown and give the skin a temporary darkening effect. While they may mimic the appearance of natural melanin, they do not provide the same level of protection against UV radiation.