How sun block and tanning lotion work...?

How does sun block protect and tanning lotion tan (lotion activates pigments somehow?)?
How sun block and tanning lotion work...?
Within your skin are cells called melanocytes. When you go out into the sun, the Ultraviolet rays in sunlight stimulate those cells to produce melanin. When melanin is exposed to UV light it oxidizes or turns darker. This darkening is your skin's way of protecting itself against too much UV light.





Sunscreens work by absorbing, reflecting, or scattering the sun's rays on the skin. Therefore it prevents the light stimulating the production melanin and therefore prevents you turning darker!





Tanning lotion causes the melanin in the skin to rise to the top layer of skin causing it to hit oxygen in the air. This causes it to oxidize faster, thus speeding up the tanning process. This is what causes the reddening and the itching. Once the melanin goes back down, the reddening subsides, along with the tingling.