Sodium Hyaluronate Crosspolymer
Also known as Cross-linked sodium hyaluronate, Crosslinked hyaluronic acid sodium salt, HA crosspolymer
“CIR Expert Panel says: restricted.”
Sodium Hyaluronate Crosspolymer (CAS 105524-32-1) is the sodium salt of a polymer of hyaluronic acid crosslinked with divinyl sulfone, forming a mesh structure with enhanced water-binding capacity. No CIR safety assessment has been completed for this INCI: the 2023 CIR Final Report on Hyaluronates explicitly excluded cross-linked HA ingredients, and this ingredient appears on the CIR 2024 Final Priority List (FOU=207) for a planned new safety assessment. PubMed literature on topical cross-linked HA as a class is limited: Lee et al. (2019, PMID 30942947) found cross-linked HA microstructure patches non-irritating and safe in a clinical study; Sundaram et al. (2018, PMID 29601621) found a topical crosslinked HA serum well-tolerated with statistically significant improvements in skin hydration. Neither study names Sodium Hyaluronate Crosspolymer by INCI and both address the broader crosslinked HA class.
Cross-linked mesh structure provides enhanced water-binding capacity relative to linear sodium hyaluronate
Non-irritating in primary skin irritation testing of cross-linked HA microstructure patches (Lee et al. 2019, PMID 30942947)
Topical crosslinked HA serum produced statistically significant improvements in skin hydration with no adverse effects in split-face RCT (Sundaram et al. 2018, PMID 29601621)
CIR 2024 Final Priority List (September 2023) — Sodium Hyaluronate Crosspolymer listed for new safety assessment, FOU=207, CAS 105524-32-1
“Sodium Hyaluronate Crosspolymer FOU = 207 Definition: Sodium Hyaluronate Crosspolymer is the sodium salt of a polymer of Hyaluronic Acid crosslinked with divinyl sulfone. Reported Functions: Skin-Conditioning Agents - Humectant; Skin-Conditioning Agents - Miscellaneous Notes: (CAS No. 105524-32-1) These 3 ingredients share the same polyhyaluronate backbone and differ only by the crosslinker (diglycidyl ether for Sodium Hyaluronate Crosspolymer-2 and propylbisoxyamine for Sodium Hyaluronate Crosspolymer-3). (The Panel has recently addressed the safety of Sodium Hyaluronate.)”— 2024_Final_Priorities.pdf, p. 6