Skin Hydration: Everything you need to know about the Natural Moisturising Factor (NMF)

There are elements that ensure hydration and its preservation at the superficial layer of the epidermis. They are also referred to as NMF, the abbreviation of their English name "Natural Moisturising Factors". These are all the hygroscopic substances responsible for maintaining hydration in the stratum corneum of the epidermis, which is the most superficial layer of the skin, directly in contact with the external environment.

The NMF constitutes up to 30% of the total dry weight of the stratum corneum. Approximately one third of the water contained in the stratum corneum is bound to NMF molecules.

In terms of its composition, it contains over 50% of free amino acids and their derivatives such as pyrrolidone carboxylic acid derived from glutamine and the urocanic acid derived from histidine. The amino acids are predominantly derived from the proteolysis of a single protein, the filaggrin. In addition to these, the NMF also includes other species such as lactic acid, urea, ceramides, mineral ions (sodium PCA, potassium, magnesium) and sugars (triglycerides and saccharides). These components are, among other things, derived from the seborrheic secretion by the sebaceous glands.

Furthermore, NMF also contains hyaluronic acid, a complex natural carbohydrate that plays a crucial role in wound healing. It is a potent humectant, capable of binding to over 1000 times its weight in water. It is also the compound that provides structure and elasticity to the skin. Therefore, it is often used for its regenerative properties, particularly in cases of wrinkles or skin sagging.

Atopic dermatitis, psoriasis, ichthyosis vulgaris, and xerosis all result in dry, flaky skin. In patients suffering from these conditions, the levels of Natural Moisturising Factor (NMF) in the stratum corneum are either reduced or absent. Ageing, systematic skin washing with soap, or excessive exposure to UV rays are also known to decrease the levels of NMF in the superficial layers of the stratum corneum.

Therefore, replenishing or restoring the skin's supply of natural moisturising components through the application of moisturising products rich in NMF is a long-standing approach to caring for dry and/or dehydrated skin.

In skincare today, there are concentrates of NMFs. These treatments are typically applied after the serum to enhance skin hydration.

Furthermore, it is recommended to apply active ingredients found in the NMF such as lactic acid, urea, sodium PCA... Some active ingredients have also demonstrated an ability to stimulate the production of molecules that make up the NMF, thus promoting skin hydration.

At Typology, we have developed various treatments whose active ingredients work to "recharge" the NMF.

• 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. Moreover, 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. Lactic acid being a photosensitising molecule, this serum should be used only in the evening. The application of a broad-spectrum sunscreen is strongly recommended the following morning.

• As a reminder, sodium PCA is one of the main components of NMF, as it is present at 14%. Our blemish-fighting and regenerating complex with 5 minerals is a revitalising serum that regulates sebum production and optimises cell renewal and longevity. The skin becomes firmer, more elastic and blemishes are reduced. It is enriched with zinc, calcium, manganese, magnesium and sodium and should be applied morning and evening, on clean, dry skin.

• Polyglutamic acid boosts the production of certain molecules including pyrrolidone carboxylic acid (PCA), lactic acid, and urocanic acid. In the plumping serum by Typology, the red algae extract is combined with polyglutamic acid to provide dual-level hydration for the skin. The red algae extract is capable of acting deeply and stimulating the production of hyaluronic acid, while the polyglutamic acid forms a protective film on the skin's surface to combat dehydration. This product should be applied morning and evening, on clean and dry skin. It is particularly recommended for dry skin and/or to prevent dehydration fine lines as well as early wrinkles.

  
  

• Marty JP, NMF and Cosmetology of Skin Hydration., Laboratory of Dermopharmacology and Cosmetology, Faculty of Pharmacy, Annals of Dermatology and Venereology, (2002).