Hyaluronic Acid or Sodium Hyaluronate: Which INCI Applies

Marketing copy says "hyaluronic acid" on almost every serum bottle, but crack open the actual ingredient deck for most of those formulas and you'll find sodium hyaluronate sitting in the INCI list instead. This isn't a labeling error, and it isn't the same molecule with a fancier name slapped on. Getting this right matters when you're filing, because the INCI name has to match what's actually in the jar, not what the front-of-pack marketing calls it.

Two different molecules, one marketing term

Hyaluronic acid is the free acid form. Sodium hyaluronate is its sodium salt, the form you get when the acid is neutralized. Cosmetic formulators overwhelmingly use the sodium salt, because it's more stable, easier to dissolve in water-based systems, and gentler on formulation pH than the free acid. "Hyaluronic acid" survived as the consumer-facing term mostly because it sounds more scientific and recognizable than "sodium hyaluronate," even though the salt is what's actually doing the work in the bottle.

If your supplier's certificate of analysis says sodium hyaluronate, that's your INCI name for the filing. Don't translate it back to "hyaluronic acid" because that's what the marketing team wants on the front label. The two live in different places: INCI on the ingredient list, marketing language on the front panel, and they don't have to match word for word as long as the ingredient list itself is accurate.

Molecular weight is a separate variable entirely

This is where it gets more interesting than a simple naming question. Sodium hyaluronate is sold in a range of molecular weights, and suppliers often market these as distinct products:

• High molecular weight versions sit on the skin's surface and form a film, mostly a humectant and texture agent
• Low molecular weight versions are marketed as being able to penetrate further into the skin
• Some suppliers sell blends of multiple molecular weights in one product, marketed as "multi-weight" hyaluronic acid complexes

None of this changes the INCI name. Whether it's a 2,000 kDa or a 50 kDa version, the INCI declaration is still Sodium Hyaluronate, because INCI names describe chemical identity, not molecular weight distribution. Molecular weight is a functional and marketing distinction, not a separate regulatory ingredient.

CAS numbers get messier than you'd expect

Hyaluronic acid and its salts have several CAS numbers associated with different forms and preparations, which is common for polymeric and biologically derived substances. If you're filing and your supplier documentation lists a CAS number, use exactly what they provide rather than guessing from a general reference, since the specific number can vary by form, source, and even manufacturing process. If your supplier can't give you a clear CAS number for their specific material, ask directly, don't leave the field blank or substitute a number you found through a general search.

A quick reference table

Common name	INCI name	Typical CAS status	Typical function
Hyaluronic acid (free acid)	Hyaluronic Acid	Multiple CAS numbers exist depending on form	Humectant
Hyaluronic acid (as usually sold)	Sodium Hyaluronate	Supplier-specific, confirm with COA	Humectant, film-former
Low molecular weight version	Sodium Hyaluronate	Same INCI, supplier-specific CAS	Humectant, marketed as more penetrating
Cross-linked / hydrolyzed variants	Sodium Hyaluronate Crosspolymer or Hydrolyzed Sodium Hyaluronate	Supplier-specific	Film-forming or smaller-fragment humectant

Notice that cross-linked and hydrolyzed variants get their own distinct INCI names entirely, they're not just "hyaluronic acid" with a modifier. If your supplier is selling you a hydrolyzed version, that's a different INCI declaration than plain sodium hyaluronate, and mixing them up on a filing is an easy, avoidable error.

What to check before you file

Pull the actual certificate of analysis or technical data sheet for your specific hyaluronic acid ingredient rather than relying on the trade name on the drum or the marketing sheet from a reseller. Confirm the INCI name matches what's on the COA, note the molecular weight range for your own records even though it won't appear on the filing, and get the CAS number directly from the supplier's documentation. This is a small ingredient to get wrong, but it's also one people get wrong constantly because "hyaluronic acid" is such an ingrained shorthand. Cosmetic Comply's ingredient matching is built to catch exactly this kind of mismatch, mapping your supplier's actual material to the correct INCI and CAS before it becomes a filing error.