What does hyaluronic acid do for skin?
The molecular weight distribution of hyaluronic acid is very wide, ranging from 800Da to 3000kDa. Due to its different molecular weights, its role in cosmetics is very different.
Hyaluronic acid is divided into 4 categories: high molecular weight hyaluronic acid, medium molecular weight hyaluronic acid, low molecular weight hyaluronic acid, and oligomeric hyaluronic acid. The larger the molecular weight, the stronger the effect of moisturizing, hydrating, and resisting ultraviolet rays on the surface of the skin, but it will not be absorbed by the skin.
The smaller the molecular weight, the easier it is to penetrate into the epidermis and dermis of the skin, achieving deep hydration, repair, and anti-aging effects.
Under physiological conditions, the carboxyl group of uronic acid in the hyaluronic acid molecule is fully dissociated. When combined with sodium ions, the integrated product formed is sodium hyaluronate (SHA), which is also the conventional form of medical products.
Is sodium hyaluronate or hyaluronic acid better?
Sodium hyaluronate is a macromolecular glycosaminoglycan commonly found in connective tissues. It is the main component of the extracellular matrix (ECM) and intercellular matrix (ICM). It can bind to specific receptors or sodium hyaluronate synthase on the cell membrane. Since sodium hyaluronate has physiological activities such as regulating cell function and inactivating free radicals, it plays an important role in morphogenesis, angiogenesis, wound healing, pain control and inflammatory response.
Sodium hyaluronate has a smaller molecule than hyaluronic acid, which allows it to penetrate the skin more deeply and provide deeper hydration.
Sodium hyaluronate is more stable and less susceptible to oxidation, making it a preferred ingredient in many skin care formulations.
Sodium hyaluronate is highly water-soluble, which enhances its ability to attract and retain water for better hydration.
2. Hyaluronic acid
Hyaluronic acid is a larger molecule and it mainly works on the surface of the skin, forming a moisture barrier and providing instant hydration.
Which is better?
If deep hydration is needed, sodium hyaluronate may be more effective because of its smaller molecule size and better penetration.
Hyaluronic acid, on the other hand, forms a moisture barrier on the skin, making it suitable for surface hydration.
Many skin care products combine the two forms, which can provide comprehensive hydration, involving the surface and deeper layers of the skin.
Reference
[1]. L.H. Chen, J.F. Xue, Z.Y. Zheng, M. Shuhaidi, Thu, H.E. Z. Hussain, Hyaluronic acid, an efficient biomacromolecule for treatment of inflammatory skin and joint diseases: A review of recent developments and critical appraisal of preclinical and clinical investigations, Int J Biol Macromol. (2018) 116: 572-584.
