how does a spray tan work?

The active ingredient 'dihydroxyacetone' (DHA) causes a chemical reaction with the amino acids of the outer most layer of the skin.  This reaction causes the colour of the skin to change, producing a beautiful natural tan.  DHA starts to react with the skin within 2 hours of the tan application and continues to do so for a total of 12 hours after which time you can wash (time may vary depending on spray tan solution used). The spray gun is used to spray a combination of air and tanning solution directly onto the skin, which dries almost immediately. In just 15 minutes you can have a flawless tan that will develop over the next 8 hours.