Dehydroxyacetone is the active ingredient in tanning products. When applied to the skin, it reacts with the amino acids in the dead skin cells on the outermost layer of the skin, resulting in a temporary browning or tanning effect. Melanin is the pigment responsible for the natural color of the skin, hair, and eyes, but it is not the active ingredient in tanning products. Hydroxyacetone is not a recognized ingredient in tanning products. Dead skin cells are not an active ingredient but rather a component of the skin that can be affected by tanning products.