Sodium Hyaluronate - INCI Ingredient Record

Aliases

• Hyaluronic acid, sodium salt
• Sodium hyaluronan / Hyaluronan sodium
• Hyaluronate sodium
• CAS 9067-32-7 (per ChemicalBook, Alfa Chemistry - retailer-grade chemical supplier listings; not independently cross-checked against a primary regulatory/academic database in this session because a PubChem fetch was blocked by tool permissions)
• NOTE: 'Sodium Hyaluronate Crosspolymer' (CAS 105524-32-1) and 'Hydrolyzed Sodium Hyaluronate' are DISTINCT INCI-registered ingredients, not synonyms - do not merge with base Sodium Hyaluronate (per SpecialChem INCI listings and a separate CIR review track: SLR_Sodium Hyaluronate Crosspolymers_032026.pdf)

Inci name

Sodium Hyaluronate

Formula context

• Molecular-weight tiering is NOT standardized across sources; two incompatible classification schemes were found and are kept side by side rather than averaged or merged:
• (A) Supplier/industry tiering (samaterials.com, retailer-class): Low MW = <1000 kDa (examples cited ~100-931 kDa), marketed for medical/injectable joint applications; Medium MW = 300-800 kDa, marketed for moisturizing/anti-wrinkle; High MW = 1500-1800 kDa, marketed for moisturizing/filming/soothing.
• (B) Penetration-based academic tiering (Nature Scientific Reports 2023; ScienceDirect liposome study; MDPI Cosmetics 2026 3 kDa study - all primary-academic): HA/SH below ~8-10 kDa ('oligomers') can cross the stratum corneum into epidermis/dermis via CD44-mediated and other interaction mechanisms; high-MW HA (patent examples cite 1100-1600 kDa) is largely trapped on the stratum corneum surface, forming a hydrating film rather than penetrating.
• These two schemes use different kDa cut-points and different underlying logic (commercial tier vs. measured penetration behavior); no single universal MW boundary is published across sources, and this record does not collapse them into one number.
• Distinct low-MW oligosaccharide grade explicitly studied for topical tolerance: 3 kDa sodium hyaluronate (MDPI Cosmetics, 2026, primary-academic: 'In Vitro and Ex Vivo Investigations on the Tolerance and Safety of a 3 kDa Sodium Hyaluronate for Topical Application').

Functional roles

• Skin conditioning agent (official CIR-recognized function) - CIR 'Safety Assessment of Hyaluronates as Used in Cosmetics' (cir-safety.org)
• Humectant (official CIR-recognized function) - same CIR source
• Marketing/trade description only, not a formal CIR function: 'film-forming conditioner,' said to leave a flexible surface film reducing transepidermal water loss - sourced from SpecialChem and skincare-education sites (secondary-media), flagged as lower-rigor than the two CIR-listed functions

Safety references

• CIR Panel, 'Safety Assessment of Hyaluronates as Used in Cosmetics' (Final Report status, FR_Hyaluronates_062023.pdf, cir-safety.org) - primary-regulatory: concluded sodium hyaluronate, hyaluronic acid, and potassium hyaluronate are safe in cosmetics under current practices of use and concentration described in the assessment.
• Same CIR assessment: notes hyaluronates may be animal-sourced (rooster combs) or produced by bacterial fermentation; recommends industry limit biologically-derived impurities (nucleic acids, proteins, endotoxins) and control heavy metals to FDA/EPA limits.
• A separate, later CIR document specific to Sodium Hyaluronate Crosspolymers (SLR_Sodium Hyaluronate Crosspolymers_032026.pdf, cir-safety.org, primary-regulatory) exists as its own safety-review track - not cited as evidence for base Sodium Hyaluronate safety since it covers a different INCI entry.
• MDPI Cosmetics (2026) in vitro/ex vivo tolerance and safety study specifically on 3 kDa sodium hyaluronate for topical application - primary-academic, peer-reviewed; supports topical tolerance at that specific low-MW grade only, not generalized to all MW grades.

Compatible systems

• Phenoxyethanol + ethylhexylglycerin preservative pairing reported as a workable, non-precipitating alternative preservative system in HA-containing formulations (US patent literature on preserved hyaluronic-acid compositions, primary-patent).
• MgCl2 co-formulation shown to increase intercellular penetration of high-molecular-weight hyaluronan through the stratum corneum by 1.5-3.0x versus other metal chlorides (Nature Scientific Reports, 2023, primary-academic).
• Co-formulation with niacinamide and stabilized vitamin C derivatives (e.g., magnesium ascorbyl phosphate, sodium ascorbyl phosphate) is widely reported as compatible in commercial skincare formulation guidance - sourced from skincare-industry blogs/brand education pages (secondary-media/community-adjacent, NOT peer-reviewed or regulatory); flagged as lower-confidence than the patent/academic entries above.

Conflicting systems

• Cationic preservatives, notably benzalkonium chloride (BAK): anionic sodium hyaluronate and cationic BAK are reported as incompatible - they conjugate and precipitate, reducing both the product's lubricating function and the preservative's antimicrobial efficacy (US patent literature on preserved hyaluronic-acid/pharmaceutically-acceptable-salt compositions, primary-patent). Documented mitigations (added surfactant, specific BAK species, nonionic tonicity agent) reduce but do not eliminate the underlying incompatibility.
• General principle corroborating the above: cationic surfactants/species are broadly documented as incompatible with anionic polymer species, with individual physicochemical properties (viscosity, charge-dependent function) becoming impaired on mixing (MDPI, 'Compatibility Investigation of Cationic Surfactants with Anionic Species', primary-academic) - cited as supporting mechanism, not as direct testing on sodium hyaluronate itself.

Concentration evidence

• CIR 2021 concentration-of-use survey (primary-regulatory, cir-safety.org / FR_Hyaluronates_062023.pdf): Sodium Hyaluronate used at up to 7.5% in leave-on face/neck products (non-spray).
• Same CIR source, earlier 2005 data point kept separate, not averaged into the above: maximum reported use was 2% at that time.
• CIR 2023 VCRP frequency-of-use survey (primary-regulatory): reported in 4,713 total cosmetic formulations (4,317 leave-on, 394 rinse-off, 2 diluted-for-bath-use products).
• Ophthalmic/medical-device literature (PMC clinical studies, primary-academic) reports 0.1%-0.2% (also 0.15%, 0.18% in some trials) sodium hyaluronate in artificial-tear formulations - a different product category (ophthalmic solution, not cosmetic skin product), not directly comparable to the CIR cosmetic-use percentages and kept as a separate data point.
• US patent literature (primary-patent, e.g. USPTO 'formulations containing hyaluronic acid' filings) describes ~1% aqueous sodium hyaluronate skincare formulations using high-MW material (1100-1600 kDa) in worked examples - patent examples are not independent clinical/regulatory concentration-of-use evidence and are labeled as such.

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