50 Shades of Tan
It is well established that tanning by natural ultraviolet (UV) light, either by the sun or tanning bulbs, creates damage which leads to premature skin aging and skin cancer especially in fair skinned individuals.
Can we safely darken our skin color and avoid the damaging effects of UV? There have been national headlines reporting that spray tanning could cause cancer, and infertility. Searches on-line for "spray-tanning risks" support these alarming headlines. These concepts are based on non-human testing using tissue cultures and animal studies which so far have not translated to human risk. The active ingredient in self-tanning prdoucts is Dihydroxyacetone (DHA). When applied to the skin, DHA combines the protein in the skin's outermost layer, the stratum corneum. Brown colored products are formed called melanoidins. When limited to the stratum corneum no systematic absorption occurs. The stratum corneum slowly sheds and is replaced in 2-3 weeks.
The FDA suggests that patients should be counseled on the safe use of DHA tanning products, especially spray-on products. Protection from systematic absorption from mucous membranes(eyes, mouth, female genitalia) and the respiratory system should be provided in the form of eye shield, lip balm, and respiratory protective face masks to prevent systematic absorption.
In summary, best current evidence suggests self-tanning DHA products in lotion and cream form are safe when applied according to instructions. The use of spray products are a bit more problematic since areas when absorption can occur must be protected.