Erythrulose

Erythrulose at a glance

Erythrulose is a self tanning active, a natural keto sugar with the INCI Erythrulose. It is sometimes called raspberry sugar, because it occurs naturally in red raspberries. The cosmetic grade is a yellowish to amber liquid from Switzerland that dissolves in water. It gives the skin a natural looking tan without sun exposure. The usual level is 3 to 5% of the finished product, intensive products can go to 10 or 15%, and a light, gradual effect can already be seen from 1%.

How sugar tans the skin

Erythrulose reacts with the free amino acids in the outermost, dead layer of the skin. This reaction, known as the Maillard reaction, is the same one that browns bread crusts and roasted coffee. It forms brown pigments called melanoidins that sit only in the surface layer and fade gradually as the skin renews itself, usually over several days. No sun exposure is needed and the natural pigment of the skin is not involved.

Why erythrulose

The supplier designed it to reduce the weak points of classic self tanners. Erythrulose develops its color more slowly, over one to two days, which gives a softer, more even result with less risk of streaks and patches. The tan tends to last longer and fade more evenly. It also has a reputation for being less drying than faster tanning sugars. Many formulators combine it with dihydroxyacetone, the classic tanning sugar, to get both a quick start and an even, long lasting finish.

The two pH values

Erythrulose has two important pH values. In the product it is most stable at pH 3 to 4, so self tanners are formulated on the acidic side. On the skin, the tanning reaction runs best at pH 5 to 6, and the skin adjusts the pH of the applied product on its own. In practice, formulate at about pH 3.5 to 4 for shelf life, and let the skin do the rest.

How to formulate

Add erythrulose to the water phase at cool-down, below about 40 °C. Avoid ingredients with free amino groups in the formula, such as proteins, amino acids and some amines, because they can react with the sugar in the bottle and turn the product brown. Choose nonionic emulsifiers and thickeners that tolerate low pH. Pack the product in opaque, airtight containers. For a hydrating self tan lotion, add humectants such as vegetable glycerin and a soothing active such as allantoin. More body care actives are listed in the cosmetic actives section.

Product ideas

Self tanning lotions and creams, gradual tan moisturizers, tanning gels, tanning milks, face self tanners and tanning drops to mix into a moisturizer are the main uses.

Sample recipe: gradual tan body lotion, 100 g

Distilled water 76.00 g, glycerin 3.00 g, glyceryl stearate 4.00 g, cetearyl alcohol 2.00 g, caprylic/capric triglyceride 6.00 g, squalane 2.00 g, xanthan gum 0.30 g, Erythrulose 4.00 g, allantoin 0.20 g, preservative 1.00 g, fragrance 0.50 g, citric acid solution 1.00 g. Heat water and oil phases to 75 °C, emulsify, cool to below 40 °C, add erythrulose, allantoin, the preservative and fragrance, and adjust to pH 3.5 to 4 with citric acid.

Consumer advice

Advise users to exfoliate before application, apply evenly, wash hands afterwards and wait for the color to develop over one to two days. A self tan does not protect against the sun, so it should be used together with.

Choosing the dose for skin tone

Light gradual tan moisturizers for fair skin work well at 1 to 3%. Medium self tanning lotions use 3 to 5%. Intensive express or dark products can use up to 10 or 15%, often together with dihydroxyacetone. Face self tanners usually sit at the lower end, because facial skin renews faster and the color should look subtle.

Storage

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