Hyaluronic acid (and in particular its sodium salt) is a popular and sometimes the most frequently used substance to combat wrinkles and other symptoms of the ageing process. It is a substance produced naturally in the body, which makes it a very well-tolerated ingredient. Active makes. For example, it is largely responsible for ensuring that the vitreous body of the eye, with its high water content, is stable and functional in the eye, enhancing its special properties and enabling us to see. But it is also present in the skin. Young skin contains particularly high levels of hyaluronic acid. However, with age, the content decreases and the skin appears less firm and less elastic. From around the age of 25, fine lines and later wrinkles and furrows begin to form.
Their skin plumping effect is based on their ability to bind enormous amounts of water. This property is closely linked to its molecular structure: Hyaluronic acid is a linear polysaccharide consisting of D-glucuronic acid and N-acetyl-D-glucosamine units. The very high density of OH groups in the molecule is decisive for its functionality as a moisturiser. These OH groups are able to bind a lot of water via hydrogen bonds: around 6 g of hyaluronic acid can bind one litre of water.
In general, both its ability to bind very large quantities of water and its good tolerability are responsible for the fact that hyaluronic acid is often used in cosmetics to delay age-related side effects.
How hyaluronic acid works
The mode of action of hyaluronic acid differs depending on its molecular mass, i.e. its size and weight. Strongly cross-linked units and therefore larger molecules (> 2000 kDa) contrast with medium-sized (approx. 1500 - 1800 kDa) and small (< 50 kDa) molecules. Due to these different sizes, the natural macromolecules penetrate the skin layers to different depths and transport moisture deep into the skin due to the OH groups mentioned above.
The different effects can be visualised very well on an eye wrinkle. The smaller molecules penetrate deepest into the skin layer and infiltrate the crease around the eye. Here they draw in water and form a kind of cushion under the wrinkle. With an application concentration of 0.1 %, the wrinkle depth can be reduced by approx. 11 % after 60 days. Long-term moisturisation is increased by around 16 % and elasticity by around 13 %. Hyaluronic acid types with a medium or higher molecular weight do not penetrate into deeper skin layers. They remain on the wrinkle and thus produce a less lasting but immediate effect. The hyaluronic acid therefore attracts water above the wrinkle and forms a cushion here.
Even though low-molecular hyaluronic acid is the most effective in terms of sustainable anti-ageing, a combination of hyaluronic acids of different weights delivers the best results in a cosmetic product.
Further effects of hyaluronic acid as a versatile Acitve, In addition to reducing some visible signs of ageing of the skin, these include
- Inhibition of inflammation
- Promotion of wound healing
- Reduction of skin irritation
- Treatment of dry eye syndrome.
Hyaluronic acid is used in both cosmetic and medical products.
