Dihydroxyacetone (DHA) is a water soluble alpha hydroxyl ketone that is the active in sunless tanning formulations. DHA reacts with amines, peptides, and amino-acids in the stratum corneum to generate brown polymers called melanoidins and after 2-6 hours a brown coloration similar to a tan is formed. (EU: Dihydroxyacetone | DHA)
If you’re working on a sunless tanning formulation (EU), use the following 11 tips to make sure your formulation with DHA is a success.
Stabilizing Tips
1. Formulate at a PH of 3-4. In water, DHA initially has a pH of 5.5 and which drifts down to 3-4 over time.
2. Avoid using metal oxides (iron oxides, titanium/zinc oxides).
3. Avoid phosphates. Don’t use pH buffering agents, many are phosphate based.
4. Avoid incorporating any amine containing ingredient (amino acids, peptides, proteins, EDTA).
5. Avoid using alpha or beta hydroxy acids.
6. Avoid using oxidizing agents.
7. Sodium Metabisulfite (EU) is an excellent stabilizer to prevent Dihydroxyacetone formulations from discoloring.
8. Add DHA to formulations at <40C.
9. Use an opaque packaging in order to avoid a UV-induced degradation of DHA.
10. Use low PH stable acryloyldimethyltaurate based polymers as thickeners, such as Aristoflex AVS by Clariant and Sepiplus S and Sepigel 305 by Seppic.
(EU: acryloyldimethyltaurate | Aristoflex | Sepiplus S | Sepigel 305)
11. Use xanthan gum and SepiMax Zen by Seppic in formulations containing high levels of electrolyte.
(EU: xanthan gum | SepiMax Zen)
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Thanks George for Your tips.
Synthalen CR (Polyquaternium-37) from 3V is self-thickening without neutralization so it improves stability and skin-feel of low pH products like AHA and DHA emulsions. It is also compatible with Iron Oxides, TiO2 and ZnO.