Chemistry behind Tanning
Updated: Jun 24, 2020
Now that its summer, everyone is trying to get their summer glow. People are tanning on the beach, balconies, and more places. The first thing to understand in tanning is melanin. Melanin is a dark substance that gives a browner color to the skin, hair, and eyes. The main purpose of melanin is to absorb radiation, which prevents the UV radiation from reaching and harming the inner cells. Skin tanning is a protective measure to increase melanin known as melanogenesis. The melanin chemical formula is C18H10N2O4. Melanin is produced by melanocytes which are in the deepest part of the outermost layer of skin. After melanin is synthesized, it is stored in melanocytes.
There are different types of melanin: eumelanin, pheomelanin, and neuromelanin. Eumelanin and pheomelanin are both made by melanocytes in the lowest layer of the epidermis. The cells start as melanoblasts in tissue. The synthesis of this starts with tyrosine, which is a molecule, and this is turned into dopaquinone, which ultimatley results in the production of melanin. However, neuromelanin is produced in the brain as a neurotransmitter of dopamine. Neuromelanin does not participate in the darkness of skin tones.
Human skin is made up of molecules such as lipids, proteins, and DNA. The atoms in the molecules have electrons that are in their ground state when they are at room temperature. The UV radiation causes the electrons to move to their excited state. The charged electrons lose their energy, which causes a chemical change. Even though your skin does get tanner and there is a production of vitamin D, sunburns, wrinkles, and tumors can occur from the toxic side of melanin.
There are two phases that occur during tanning. The first one is the immediate darkening of the pigment. This phase shows rapid darkening in the skin during exposure to the sun. It can also fade within minutes if radiation exposure is at a minimum, but it can also last several days after long exposures to the sun light. The second phase is known as "delayed tanning." This is the increase within melanin production that only becomes visible 72 hours after exposure to the sun. For the second phase to happen, you need to have been in the sun for a long time.
Have fun tanning, but keep social distancing! Stay safe!