Sodium Hyaluronate

Sodium hyaluronate is the salt form of hyaluronic acid, a substance that naturally occurs in skin. HA is a very large molecule with repeating units, much like a sponge, to bind water and keep the skin hydrated, plump, and elastic. Indeed, HA can hold up to 1,000 times its weight in water, making it an exceptional hydrator.
The two are often used interchangeably in skincare, as in solution, sodium hyaluronate breaks down into hyaluronic acid itself and a sodium ion. On the other hand, some say that sodium hyaluronate penetrates skin better because of its smaller size. This is not exactly true. Both forms are similar polymers, and their molecular weight can vary. Sodium hyaluronate has a high molecular weight of around 1.5 to 1.8 million Daltons and behaves like other large HA molecules.
The key differences between sodium hyaluronate and hyaluronic acid are that sodium hyaluronate is more stable, easy to formulate, and cost-effective, hence its wide usage in personal care. However, the minute details about how HA could penetrate skin and what makes HMW different from low-one are still under scientific research which shall be furthered.