What is the difference between sodium hyaluronate and hyaluronic acid?

Sodium hyaluronate is the salt form. Its smaller ionic structure is more water-soluble and more stable, which is why cosmetics usually use it.

Does molecular weight matter?

Yes. High-molecular-weight HA forms a hydrating film on the surface; low-molecular-weight or hydrolysed HA penetrates further into the epidermis.

Cosmetic-grade material is now made almost universally by bacterial fermentation rather than extracted from rooster combs, making it vegan-compatible.

How should I apply it?

On damp skin, followed by an occlusive moisturiser — particularly in dry air, where an unsealed humectant can draw moisture from deeper layers to the surface.

Is more hyaluronic acid better?

No. Formulas commonly use 0.1%–2%, and beyond roughly 2% there is no proportional gain; higher levels can just feel tacky.

Sodium Hyaluronate — Ingredient Guide

How it works

Sodium hyaluronate, CAS 9067-32-7, is the sodium salt of hyaluronic acid — a glycosaminoglycan found naturally throughout human connective tissue, skin and joints. It is the more common cosmetic form for a straightforward chemical reason: its smaller ionic salt structure is more water-soluble and more stable than the free acid. Cosmetic-grade material was historically extracted from rooster combs but is now made almost universally by bacterial fermentation, typically with Streptococcus strains or increasingly with bioengineered Bacillus, which improves purity and consistency and makes it vegan-compatible. As a humectant it binds many times its own weight in water, drawing moisture into the stratum corneum. Molecular weight decides where it acts: high-molecular-weight material sits on the surface forming a hydrating film, while low-molecular-weight or hydrolysed material penetrates further into the epidermis.

The evidence

Clinical evidence for topical HA in its various molecular weights is well established for measurably increasing skin hydration and reducing the appearance of fine dehydration lines in the short term. A common formulation strategy stacks several molecular weights together so the product hydrates at more than one depth at once. HA also has endogenous roles in inflammation and wound healing through CD44 and other cell-surface receptors, but that biology is more relevant to injectable and dermal contexts than to a topical cosmetic.

Suitability

Suitable and generally beneficial for all skin types, including oily and acne-prone skin, because it hydrates without adding oil.

Concentration

Commonly formulated at 0.1%–2% total HA content. HA binds water so efficiently that even low percentages produce a measurable effect, and going much beyond 2% does not confer proportionally more benefit — it can simply feel tacky.

Conflicts & combinations

Broadly compatible with every other active. Apply to damp skin and follow with an occlusive moisturiser, especially in low-humidity environments, so the water it attracts is held in place rather than lost.