Sunless tanning products have come a long way from their initial debut on the cosmetic market in 1959. Dihydroxyacetone (DHA) remains the most effective and popular ingredient for providing a sunless tan, despite the numerous challenges the ingredient poses for the cosmetic formulator. Early sunless tanning products suffered from problems with unnatural, dark orange tones and uneven deposition of color. These issues led formulators to develop daily moisturizers that gradually provided a more natural color. Such products became so successful that consumer demand resulted in product shortages and caused eBay bidding wars.
Other approaches to improving the artificial tanning process have included the use of amino acid derivatives and antioxidants in combination with DHA to accelerate the browning reaction, thus more closely replicating the tonality of a natural tan. However, there are still challenges to formulating with DHA that must be overcome. Following is a review of those challenges—including formulation stability, malodor produced during the browning reaction, compatibility issues with sun protection ingredients, and the generation of free radical damage. In addition, the author suggests some solutions to these challenges.
Lab Practical: Using DHA
- The final formulation pH must be below 5 for DHA stability.
- Avoid incompatible ingredients, especially those that contain nitrogen; go beyond the INCI name and look at the full spectrum of compounds in the raw ingredient, since even trace amounts of these materials can cause problems.
- When creating emulsions, add DHA as if it were any other sensitive ingredient—i.e., at the end of the compounding process to avoid contact with heat.
- Evaluate stored DHA periodically to check for degradation. Using a raw material that has degraded can cause variability in formulation stability and color development.
- Evaluate extracts and other formulation additives in solutions of DHA prior to creating full formulations to rule out imcompatibilities.