Sunless tanning is a way to get a tan without exposing your skin to the sun's harmful ultraviolet (UV) rays. It involves applying a product to your skin that contains dihydroxyacetone (DHA), which reacts with the amino acids in your dead skin cells to produce a brown color. The tan will last for several days until the dead skin cells naturally exfoliate. Sunless tanning is a safer alternative to sun tanning and tanning beds, which can increase your risk of skin cancer.