What can replace hyaluronic acid?

Thehyaluronic acid is highly valued for its moisturising and plumping functions. Being very hydrophilic in nature, this sugar has the ability to bind to water molecules and retain a large amount of them, up to 1,000 times its weight in water, within the cells. It thus helps to limit the natural evaporation of water and restore hydration balance to normal levels in order to maintain moisturised skin. Its topical application also temporarily reduces the depth and surface area of wrinkles.

In facial skincare, hyaluronic acid can be of high molecular weight, remaining on the skin's surface to form a protective film against external aggressions and dehydration, or of low molecular weight, enabling it to cross the skin barrier and infiltrate the layers of the epidermis where it captures and gels water for a plumping effect on the surface and maximum hydration. It also serves as a signalling molecule, instructing fibroblasts to synthesise new hyaluronic acid molecules. The smaller the molecular weight of the active ingredient, the greater its penetration into the skin and the hydration it provides. Although for the majority of people, low molecular weight hyaluronic acid hydrates the skin deeply, others may be allergic to it.

Although these adverse effects are extremely rare, given that hyaluronic acid is not typically an allergenic ingredient, a few cases of allergy to hyaluronic acid can be described. It can cause inflammatory reactions of the skin. These are characterised by redness, itching, increased skin sensitivity, irritation and a rash, which will manifest immediately after applying a hyaluronic acid-based skincare product to the skin.

If you do not tolerate hyaluronic acid treatments, be aware that there are alternatives available to continue benefiting from their hydrating powers.

• Lactic Acid : (INCI name: Lactic Acid) : Studies have shown that the topical application of lactic acid in small amounts increases skin hydration. Its unique structure gives it the ability to retain water molecules within the epidermis, thus limiting the phenomenon of transepidermal water loss. Furthermore, another study demonstrated that it promotes the biosynthesis of lipids in the stratum corneum, particularly ceramides, thereby strengthening the skin barrier. Lactic acid is believed to be metabolised into acetyl-coenzyme A, which is then used as a carbon source for lipid biosynthesis;

• Aloe vera (INCI name: Aloe Barbadensis Leaf Juice): Due to its composition rich in mono-, polysaccharides and amino acids (histidine, arginine, threonine, serine, glycine and alanine), studies have revealed that aloe vera extracts can improve skin hydration through a humectant mechanism. In other words, they work by drawing water from the other layers of the epidermis to the most superficial layer. As a result, aloe vera has the ability to increase the water content of the stratum corneum, also improving the physical and chemical properties of the skin surface to make it smooth and soft;

• Beta-glucan (INCI name: Sodium Carboxymethyl Beta-Glucan): Derived from cereals (rice, wheat, barley, oats...) or microorganisms (yeast, bacteria, fungus...), this natural polysaccharide helps to slow down the skin's water loss and minimise the appearance of dehydration fine lines. Indeed, studies have found that beta-glucan can promote the biosynthesis of skin cells and collagen, despite its large molecular size. It has been demonstrated that beta-glucan can penetrate deeply into the skin through the intercellular space;

• D-panthenol (INCI name: Panthenol): This compound also has a moisturising property. Studies have shown that the application of a formula containing panthenol resulted in a significant reduction in transcutaneous water loss and an increase in the hydration of the stratum corneum. This is explained by the ability of provitamin B5 to stimulate the synthesis of fatty acids that make up the protective barrier of the epidermis, thereby improving skin hydration;

• Lactobionic Acid (INCI name: Lactobionic Acid), Gluconolactone (INCI name: Gluconolactone), etc. : Thanks to their structure, PHAs are considered excellent humectants that have a strong affinity for water molecules due to their numerous hydroxyl groups (-OH). Indeed, they have the ability to bind large amounts of water and retain them in the superficial layers of the skin to maintain a plump and replenished appearance;

• Glycerine (INCI name: Glycerin): It is one of the most effective humectant polyols, alongside sorbitol and mannitol. Distributed in the stratum corneum, glycerol creates a "reservoir" within the lipid bilayers, where it is hypothesised to interact with the lipid structures or proteins of the stratum corneum to alter their water-binding properties. Its structure is what gives it these hydrating effects. Glycerine has three hydroxyl groups (-OH) which are responsible for its hygroscopicity. Indeed, they bind and retain water. However, the hydrating effect of glycerol on the skin is dependent on the amount absorbed into the stratum corneum: skin hydration increases linearly with the amount of humectant accumulated;

• Niacinamide (INCI name: Niacinamide): Also known as vitamin B3, niacinamide is believed to have the ability to stimulate the production of ceramides and other intercellular lipids in the epidermis. These, in turn, help to strengthen the skin's barrier function to limit moisture loss, thereby maintaining hydrated and plumped skin for longer;

• Sodium PCA (INCI name: Sodium PCA): Numerous studies have shown that Sodium PCA can increase the water content of the skin's upper layers. Thanks to their ionic charges, this PCA derivative is capable of attracting moisture from the air and retaining water molecules in the stratum corneum, up to 250 times its weight;

• Urea (INCI name: Urea): The hydrating action of this polar molecule has been extensively studied over the years. The data has shown that urea can significantly reduce water loss through evaporation, thereby helping to improve and maintain the skin's hydration levels. Under conditions of high humidity, urea is capable of increasing the water content in the stratum corneum by binding to water molecules.

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