Spray tanning is a form of self tanning (or sunless tanning) where a fine mist is sprayed onto your body. This mist has an ingredient in it called Dihydroxyacetone (DHA) that interacts with your own skin’s chemistry to turn it tan, or bronze.
This temporary effect generally lasts from 3-7 days and is completely safe for your skin (although it doesn’t provide any protection against the sun’s rays). The results you can get from tanning sprays are generally very good. Many celebrities and models prefer spray tanning to just about anything else to get the color they want.