A spray tan never sees the sun. The color comes from a simple chemical reaction on the very surface of your skin, and once you understand that reaction, most spray tan advice starts to make sense.
The ingredient behind almost every sunless tan
The active ingredient in most sunless tanning products, including professional spray solutions, is dihydroxyacetone, usually shortened to DHA. DHA reacts with amino acids in the outermost layer of the skin, the stratum corneum, and that reaction produces brown pigments. Chemists group it with the same family of browning reactions that color toast and seared food.
Because the reaction happens only in those outer cells, a sunless tan is not a change to your natural pigment. It sits in skin that your body is already in the process of shedding.
Why the color takes time to develop
The browning reaction is gradual. Color usually starts to appear within a few hours and keeps deepening for several hours after that, which is why every product and technician gives a development window before your first rinse. The exact timing depends on the formula, so follow the instructions you are given rather than a general rule.
Why it fades after about a week
Your skin constantly renews itself from below while the surface cells flake away. As the tanned cells shed, the color fades with them. Most people see a sunless tan last roughly a week, with the exact length depending on skin type, the product used and how the skin is cared for afterward.
Bronzers and guide color
Many spray solutions and self tanners also contain a cosmetic bronzer. This is a wash-off tint that gives instant color and shows where the product has been applied, so coverage is easier to see. When you take your first shower, some of that guide color rinses away. That is normal, and the DHA color underneath continues to develop.
What the FDA says about DHA
The U.S. Food and Drug Administration lists DHA as a color additive for use on the outside of the body. According to the FDA, it should not be inhaled, ingested or applied to areas covered by mucous membrane, including the lips, nose and the area in and around the eyes.
The FDA also notes that the all-over misting used in spray tanning booths has not been approved, because safety data to support that use has not been submitted to the agency. Its advice to consumers is to ask for measures that protect the eyes and mucous membranes and prevent inhalation during a spray session.
A spray tan is not sun protection
This is the point most often misunderstood. A sunless tan does not protect you from UV. Tanning products that do not contain sunscreen must carry an FDA-required warning that reads, in part: “This product does not contain a sunscreen and does not protect against sunburn.” Keep using a broad-spectrum sunscreen whenever you are outdoors, tan or no tan.
Quick summary
- DHA reacts with the outermost layer of skin to create a temporary brown color.
- Color develops over several hours, so follow the development time you are given.
- The tan fades as surface skin cells shed, usually over about a week.
- Protect your eyes, lips and nose, and avoid breathing in the spray.
- A sunless tan offers no protection from the sun.
Getting ready for an appointment? Read our spray tan preparation checklist.