Hyaluronate and hyaluronic acid are essentially the same molecule, just in slightly different chemical states. The difference comes down to a single sodium ion: hyaluronic acid is the pure acid form, while sodium hyaluronate is its sodium salt. In practice, these terms (along with “hyaluronan”) are used interchangeably across skincare, medicine, and supplement labels because they deliver the same functional benefits once inside your body.
The Actual Chemical Difference
Hyaluronic acid has acidic groups along its molecular backbone. When those acidic groups are neutralized by sodium ions, the result is sodium hyaluronate. That’s the entire distinction. It’s comparable to the difference between citric acid and sodium citrate, or between ascorbic acid and sodium ascorbate. Same core molecule, different ionic form.
Here’s what makes this distinction mostly academic: inside your body, at a normal pH of around 7.4, the molecule exists as a negatively charged polyanion regardless of which form you started with. The acidic groups on hyaluronic acid have a pKa of roughly 3 to 4, meaning they’re almost entirely ionized at physiological pH. Your body converts hyaluronic acid into its ionized (salt-like) form automatically. This is why scientists increasingly prefer the umbrella term “hyaluronan” to cover all forms.
Why Skincare Products Use Sodium Hyaluronate
If you check the ingredient list on a serum or moisturizer that advertises “hyaluronic acid,” you’ll almost always find “sodium hyaluronate” listed as the actual INCI (International Nomenclature of Cosmetic Ingredients) name. Brands market the ingredient as hyaluronic acid because that’s the term consumers recognize, but they formulate with the sodium salt for practical reasons. Sodium hyaluronate is more stable in water-based formulations, dissolves more easily, and is simpler to work with during manufacturing.
What matters far more than acid versus salt is the molecular weight of whichever form you’re using. A study testing 12 different hyaluronic acid molecules at various sizes found that smaller molecules penetrate skin significantly better. Molecules under 100 kilodaltons showed penetration rates of 14% to 19% through both the outer skin layer and the deeper dermis. Larger molecules only achieved 2.7% to 10.2% penetration. Both forms of the molecule come in a range of molecular weights, so the size you choose has a bigger impact on performance than whether the label says “hyaluronic acid” or “sodium hyaluronate.”
Many modern serums use a blend of molecular weights. Larger molecules sit on the skin’s surface and provide immediate hydration, while smaller ones penetrate deeper for plumping and anti-aging effects.
How Much Water It Actually Holds
You’ve probably seen the claim that hyaluronic acid can hold 1,000 times its weight in water. A detailed analysis of the actual scientific measurements tells a different story. Across multiple studies using different methods, hyaluronic acid strongly binds somewhere between 0.36 and 0.86 grams of water per gram of the molecule. That’s less than its own weight in water, not a thousand times more. The molecule does attract and loosely associate with additional water beyond what it tightly binds, which is why it’s still an excellent humectant. But the “1,000 times” figure is a marketing myth that has been repeated so often it’s taken as fact.
Medical and Joint Health Uses
In medicine, sodium hyaluronate is the standard form used for joint injections in people with knee osteoarthritis. These viscosupplementation treatments work by supplementing the joint’s natural lubricating fluid, which contains hyaluronan. Clinical protocols typically use sodium hyaluronate at concentrations between 1.6% and 3%, delivered either as a single injection or a series over several weeks.
Sodium hyaluronate is also widely used in eye drops for dry eye relief and as a surgical aid during cataract procedures, where it helps protect delicate tissues. In all these medical applications, the sodium salt form is chosen because it’s more soluble and stable in the solutions that need to be injected or applied.
How It’s Commercially Produced
Hyaluronic acid was originally extracted from rooster combs, but nearly all commercial production today uses microbial fermentation. Bacteria, most commonly Streptococcus zooepidemicus, naturally produce hyaluronan as a protective capsule. Manufacturers culture these organisms, harvest the hyaluronan they produce, and then purify it through a series of steps that remove bacterial proteins and other contaminants. The final product is typically sodium hyaluronate powder, which formulators then incorporate into creams, serums, supplements, and medical devices.
Engineered strains of other bacteria, including Bacillus subtilis and Corynebacterium glutamicum, are increasingly used as alternatives. These offer advantages in scalability and can be tuned to produce specific molecular weight ranges depending on the intended application.
Reading Product Labels
When you’re shopping, you may encounter several related names on ingredient lists. “Sodium hyaluronate,” “hyaluronic acid,” “hydrolyzed hyaluronic acid,” and “hydrolyzed sodium hyaluronate” all refer to variations of the same molecule. The “hydrolyzed” versions have been broken into smaller fragments for better skin penetration. Some products list “sodium hyaluronate crosspolymer,” which is a modified version designed to form a film on the skin for longer-lasting surface hydration.
None of these variations represent a fundamentally different ingredient. They’re all built from the same repeating sugar units, just processed to different sizes or slightly modified for specific performance characteristics. If a product claims its form of hyaluronic acid is dramatically superior to sodium hyaluronate (or vice versa), that’s marketing, not chemistry.