The Difference Between Hyaluronic Acid and Sodium Hyaluronate

Hyaluronic acid and sodium hyaluronate are both very common in skincare and medical fields, but they differ significantly in chemical structure, stability, and applications.

Hyaluronic acid is a natural polysaccharide found in human skin, synovial fluid, and eye tissues, possessing an extremely strong water-retention capacity. It can absorb hundreds of times its own weight in water, providing hydration and elasticity to the skin. However, pure hyaluronic acid has a relatively large molecular weight, resulting in limited water solubility and stability. When used directly in skincare formulations, it tends to form viscous solutions, leading to slower absorption and potentially affecting formulation stability.

Sodium hyaluronate is the sodium salt of hyaluronic acid, prepared by neutralizing acidic carboxyl groups. Compared to pure hyaluronic acid, sodium hyaluronate has smaller molecules, better water solubility, stronger permeability, and is more stable under different pH conditions. This makes sodium hyaluronate easier for the skin to absorb in skincare products and allows for compatibility with other ingredients, making it widely used in creams, serums, masks, and injectable formulations.

Furthermore, sodium hyaluronate can achieve different levels of skincare effects depending on its molecular weight. High molecular weight sodium hyaluronate primarily forms a water-locking film on the skin's surface, providing immediate hydration; low and ultra-low molecular weight sodium hyaluronate can penetrate deeper into the epidermis, improving fine lines and skin softness. This flexible molecular weight design allows formulators to finely design products tailored to different skin types and needs.

Overall, hyaluronic acid is suitable for emphasizing natural sources and inherent moisturizing properties, while sodium hyaluronate is more suitable for skincare applications, balancing permeability, stability, and user experience. Understanding the differences between the two helps in selecting ingredients more scientifically and achieving ideal skincare results.