Hyaluronic Acid
Also known as Hyaluronic acid, Hyaluronane, HA, Hyaluronan (free acid form)
“CIR Expert Panel says: safe as used in cosmetics.”
Hyaluronic Acid (CAS 9004-61-9) is the free-acid form of hyaluronan, a naturally occurring glycosaminoglycan composed of repeating β4-glucuronic acid-β3-N-acetylglucosamine disaccharides with molecular weights ranging from ~5 to 1,800 kDa. It is less common in finished cosmetics than its sodium salt (Sodium Hyaluronate, CAS 9067-32-7), though functionally equivalent as a humectant. The 2023 CIR Hyaluronates group assessment (FR_Hyaluronates_062023.pdf, July 7, 2023) re-reviewed the 3 ingredients originally assessed in 2009 (Hyaluronic Acid, Potassium Hyaluronate, Sodium Hyaluronate) plus 4 additional hyaluronate derivatives (Hydrolyzed Calcium Hyaluronate, Hydrolyzed Hyaluronic Acid, Hydrolyzed Sodium Hyaluronate, Sodium Acetylated Hyaluronate). The Expert Panel concluded all 7 ingredients are safe in the present practices of use and concentration described in the safety assessment, supported by the high molecular weight (limiting dermal absorption), the presence of Hyaluronic Acid as an endogenous substance in skin, and extensive use with few reported adverse effects. According to 2023 VCRP data, Hyaluronic Acid is reported in 663 formulations at concentrations up to 0.83% (rinse-off).
Potent humectant — 1 g of Hyaluronic Acid can bind up to 6 L of water (per 2023 CIR assessment)
Structurally identical to endogenous hyaluronan, supporting excellent biocompatibility
High molecular weight (5–1,800 kDa) limits dermal absorption; the majority deposits in the stratum corneum at ~25 μm depth (dermal penetration data, 2023 CIR assessment)
CIR Expert Panel re-reviewed and concluded safe as used in cosmetics (FR_Hyaluronates_062023.pdf, July 7, 2023)
CIR Safety Assessment of Hyaluronates as Used in Cosmetics (Final Report, July 7, 2023) — Hyaluronic Acid (CAS 9004-61-9) named directly …
“The Expert Panel concluded that the 7 following hyaluronate ingredients are safe in cosmetics in the present practices of use and concentration described in the safety assessment: Hyaluronic Acid, Hydrolyzed Calcium Hyaluronate, Hydrolyzed Hyaluronic Acid, Hydrolyzed Sodium Hyaluronate, Potassium Hyaluronate, Sodium Acetylated Hyaluronate, Sodium Hyaluronate”— FR_Hyaluronates_062023.pdf, p. 13