How is lactic acid produced?

It was the Swedish chemist, Carl Wilhelm Scheele, who first extracted lactic acid from milk. However, despite this name, lactic acid is also present in certain fruits and vegetables, in wine, and also in the skin as it is part of the Natural Moisturising Factor (NMF).

Please note: the NMF or Natural Moisturising Factor accounts for 30% of the total dry weight of the stratum corneum. It is composed of amino acids, their derivatives, and extracellular compounds such as lactic acid or urea. Its hygroscopic properties allow it to capture and retain water in the stratum corneum, thus maintaining good skin hydration.

Lactic acid offers numerous benefits for the skin. In cosmetics, it is a widely used active ingredient due to its keratolytic, moisturising, and depigmenting properties. It is highly valued because, unlike glycolic acid, it has a gentle exfoliating power. Therefore, lactic acid is suitable for all skin types, even the most sensitive ones.

In the majority of cases, lactic acid is obtained through a natural process. Indeed, this process results from the fermentation of various carbohydrates such as corn, sugar, or even the lactose found in milk with the help of microorganisms. Depending on the strain used, we can obtain either the L(+) form of lactic acid or the D(-) form of lactic acid. However, the L(+) form is the biologically active form of lactic acid that is found in the NMF. The L(+) form of lactic acid is obtained, among other things, by microorganisms of the Lactobacillus genus.

There are also synthetic methods for obtaining lactic acid, such as the degradation of sugars or the oxidation of propylene glycol. However, the resulting product is an inactive racemic mixture of the two enantiomers L(+) and D(-) of lactic acid.

Please note : in chemistry, some molecules can exist in two different configurations, this is referred to as enantiomerism. We differentiate between levorotatory (L) and dextrorotatory (D) compounds based on their rotational power. Some molecules are active only in one of the two forms.

As previously mentioned, it is the L(+) form of lactic acid that is biologically active. This form is obtained, among other ways, by microorganisms of the Lactobacillus genus.

We have formulated a serum containing 10% lactic acid. Highly concentrated, it provides your skin with gentle exfoliation due to its superficial action. By ridding the skin of its dead cells, our gentle peeling serum revives the complexion's radiance and fights against imperfections. The skin is smooth and glowing. Additionally, it contains an antioxidant, theacerola extract, which combats the free radicals responsible for a dull complexion. Our serum is suitable for all skin types (oily, dry, and combination skin). It is also suitable for sensitive skin as, unlike glycolic acid, it is non-irritating and penetrates less deeply.

Our peeling mask combines the exfoliating action of 4 types of A.H.A. and a P.H.A.. to act at different depths of the epidermis. It removes dead cells to refine the skin texture and even out the complexion. By unclogging the pores, this gel-mask helps to smooth the skin texture and prevents the appearance of blackheads. However, its high concentration of A.H.A. makes its use not recommended for sensitive skin.

Lactic acid being a photosensitising molecule, these treatments should be used only in the evening. The application of a broad-spectrum sunscreen is highly recommended the following morning.

Before any use of our lactic acid treatments, perform a skin tolerance test. Apply a few drops of your treatment to the inside of your arm or the back of your hand and wait 24 hours. If you observe any skin reaction, do not use the product on your face.

• Rotsztejn H. & al. Lactic and lactobionic acids as typically moisturising compounds. International Journal of Dermatology (2018)