DHA Self Tanning Agent

INCI - Dihydroxyacetone.

What is it - Dihydroxyacetone (DHA) is an ingredient used in self-tanning products to give the skin a temporary tanned look without sun exposure. In cosmetic formulations, it reacts with the dead skin cells on the surface to create a brown colour, which looks like a natural tan. The tan usually develops within a few hours and fades over a few days as the skin naturally sheds.

pH - Formulate to just below 6, pH will drop over time.

Safety limit - Up to 10% in creams and lotions and up to 14% in spray on products.

Formulas used in - Self tanning products.

Formulation notes - Use only non ionic waxy emulsifiers, use these in high inputs to build body in emulsions. Use non ionic thickeners such as hydroxyethylcellulose (HEC). Do not use alkali such as tromethamine and sodium hydroxide. You cannot bring the pH of the formula up, only take it down with citric acid. Your formula needs to be just below 6, if it isn't you must start again. Use high amounts of humectants (glycerin, propylene glycol) and rich lipids to offset the drying effect.

Odour - Due to the Maillard reaction DHA can result in a biscuity or malty smell when applied to skin. The Maillard reaction is the name of the chemical reaction that occurs when DHA reacts with amino acids in the top layer of your skin, causing the browning effect.

Form - White powder.

Heat sensitivity - Very heat sensitive add in cool down phase <38°C.

Solubility - Insoluble in water, soluble in organic solvents.

Natural / synthetic status - Naturally derived.

Contraindications - Dihydroxyacetone (DHA) is generally safe for topical use but should not be applied to broken or irritated skin. It may cause mild irritation in sensitive individuals. It should not be inhaled, especially in spray tanning products, as its safety via inhalation hasn't been fully established. DHA does not provide sun protection, and the skin may be more sensitive to UV rays for up to 24 hours after use, so using a broad spectrum sunscreen is recommended.