Hydrolyzed Hyaluronic Acid

Hydrolyzed hyaluronic acid is a low–molecular weight humectant used at low concentrations (typically well under a few percent) to bind water and improve hydration, and hyaluronans are generally well-tolerated in clinical use and patch testing. Compared with higher–molecular weight sodium hyaluronate, the hydrolyzed/low-MW form has a slightly higher likelihood of stinging on very compromised barriers and can rarely provoke irritation in highly reactive eczema patients, especially in leave-on products layered with other actives. Overall, its inherent irritancy is low and it is usually safe for sensitive skin, but not “inert,” warranting a very gentle (0.2) score. Safety Notes: In commercial skincare, hydrolyzed (low–molecular weight) hyaluronic acid is commonly used at very low levels (about 0.001–0.05%) in lotions, toners, and rinse-off cleansers as a secondary humectant/label claim, often alongside standard sodium hyaluronate. High-strength OTC leave-on serums and ampoules marketed for intensive hydration are observed up to ~0.5–1.0% hydrolyzed HA, with higher levels becoming impractical due to tackiness/film feel, viscosity changes, and diminishing sensory stability; rinse-off products generally sit at the low end of this range.