What it is
Sodium hyaluronate is the sodium salt of hyaluronic acid, an anionic glycosaminoglycan made of repeating units of D-glucuronic acid and N-acetyl-D-glucosamine. Hyaluronic acid occurs naturally in the body, including skin, connective tissue, joint fluid, and the vitreous of the eye, where it binds water and forms a hydrating gel. As the salt form, sodium hyaluronate is more soluble and more stable in water-based formulas, so it is the version most often used in cosmetics. In skincare and sunscreens it acts as a humectant that draws and holds water at the skin surface.
Safety & warnings
Sodium hyaluronate mirrors a substance the body already makes and is generally well tolerated, including by sensitive and acne-prone skin. It is functionally interchangeable with hyaluronic acid in formulas, dissociating into the same molecule in solution, so claims that one form penetrates dramatically better than the other are not chemically well supported.
Origin & sourcing
Hyaluronic acid was historically extracted from animal tissue such as bovine eyes and rooster combs, but most cosmetic and pharmaceutical material is now produced by microbial fermentation using bacteria, which avoids animal sourcing and improves consistency. Sodium hyaluronate is the sodium salt of this polymer, prepared because it is more soluble and stable than the free acid.
History
Hyaluronic acid was first isolated in 1934 by Karl Meyer and John Palmer from the vitreous body of a cow's eye. Its name comes from the Greek hyalos, meaning glass-like, reflecting that source, combined with uronic acid. Later development of bacterial fermentation made large-scale, animal-free production possible for skincare and medical uses.
Questions everyone asks
What is the difference between hyaluronic acid and sodium hyaluronate?
Sodium hyaluronate is the sodium salt of hyaluronic acid. It is more soluble and stable in water-based products, and in solution it dissociates back into hyaluronic acid, so they perform similarly.
What does sodium hyaluronate do in sunscreen?
It acts as a humectant, binding water at the skin surface to help keep the formula hydrating and comfortable to wear.
Is sodium hyaluronate safe for sensitive skin?
It is generally well tolerated because it resembles a substance naturally present in skin, though, as with any product, individual reactions are possible.