DHA Naturelle

DHA Naturelle at a glance

DHA Naturelle is a self tanning active from France. It consists of 100% dihydroxyacetone, INCI Dihydroxyacetone, often shortened to DHA. It is a white powder with a slight grey tint that dissolves in water and can be dispersed in oil. The supplier gives two use levels: 1 to 4% for evening out skin tone and 4 to 8% in self tanning sprays and emulsions. The finished product should have a pH of 4.5 to 6.0.

How self tanning works

DHA is a simple sugar, the smallest member of the ketose sugar family. When it is applied to the skin, it reacts with the amino acids in the proteins of the outermost layer of the skin, the stratum corneum. This reaction, known as the Maillard reaction, is the same one that browns bread crust. It forms brown compounds called melanoidins, which give the skin the color of a tan. The color develops over two to six hours and fades within about a week as the outer cells naturally shed. Because the reaction happens only in the outermost layer, the tan is purely cosmetic.

What it does

The supplier describes a warm tan tone and a healthy glow. At low levels, 1 to 4%, DHA gives a light, gradual color that helps even out the look of the skin tone. At 4 to 8% it gives a clear self tan in sprays, gels and lotions.

How to formulate

pH

DHA is most stable at pH 4.5 to 6.0. At higher pH it breaks down and can give an orange tone. Buffer the formula and check the pH over time.

Addition point

Add the powder to the active phase of the emulsion below 40 °C. Dissolve it in a little water first.

Ingredients to avoid

DHA reacts with amino groups, so avoid amino acids, proteins, some amines and high levels of certain thickeners in the same formula. Choose nonionic emulsifiers and stable thickeners such as xanthan gum or hydroxyethylcellulose. A hydrating base with hydrolyzed sodium hyaluronate and a little aloe vera gel supports an even finish. More actives are listed in the cosmetic actives section.

Product ideas

The supplier lists emulsions of various textures such as creams, cushion products and milks, self tanning gels, water sprays, tone evening creams and creams that smooth the look of skin tone after sun exposure. Typical concepts are gradual tan day creams, face tanning drops, body tanning mousses and clear tanning sprays.

Sample recipe: gradual tan body lotion, 100 g

Distilled water 75.50 g, glycerin 3.00 g, glyceryl stearate 3.00 g, cetearyl alcohol 2.00 g, caprylic/capric triglyceride 8.00 g, xanthan gum 0.30 g, DHA Naturelle 4.00 g, panthenol 1.00 g, preservative 1.00 g, fragrance 0.20 g, citric acid solution 2.00 g. Heat water and oil phases to 75 °C, emulsify with the nonionic emulsifier and cool, dissolve DHA in a little water and add it below 40 °C with panthenol, the preservative and fragrance, and adjust to about pH 5.

Use tips

Recommend exfoliating before applying, applying evenly with a mitt, washing hands afterwards and avoiding the eyes. A self tan does not protect from the sun, so advise.

Face tanning drops

A popular modern format is a clear tanning concentrate that the user mixes into a moisturizer. Dissolve 5 to 8% DHA in a water and glycerin base with a little hyaluronic acid and adjust the pH to about 4.5. A few drops in a day cream give a light, natural color that builds over days.

Stability and packaging

DHA slowly loses activity at high temperatures and in contact with metals. Use plastic or glass packaging and avoid metal parts that touch the product. Keep the finished product cool and check the pH during stability testing.

Safety notes

Avoid contact with the eyes and do not exceed the recommended dose.

Storage

Store in a dry, dark place in a tightly closed container. A certificate of analysis comes with every lot.