The main ingredient of self-tanning products is DHA, which is also an FDA-approved food colouring agent. This compound binds to the protein in the skin cells and produces melanin. This melanin is responsible for making your skin look darker. There is no evidence to suggest that DHA causes any type of harm when you apply it on the skin. Rather, they only affect the thin outside layer of the skin that will wear off in a few days. But you should be careful not to ingest or inhale any tanning products. Don’t apply tan around close to your lips, eyes, or nose.