Glycogen

Glycogen is a large polysaccharide used in cosmetics primarily as a humectant/skin-conditioning agent, typically at low percentages, and it is not pH-dependent or inherently bioactive like exfoliating acids. Available safety/patch-test data and its polymeric, water-binding nature suggest a low likelihood of stinging or barrier disruption, though any biologically derived carbohydrate can rarely trigger irritation or contamination-related reactions in highly reactive eczema patients. Given sensitive-skin risk management, it fits best as very gentle rather than completely inert. Safety Notes: In commercial skincare, glycogen is typically used as a skin-conditioning/humectant-support ingredient in leave-on serums and creams at low levels (~0.01–0.3%), often as part of a broader “energy/anti-fatigue” complex where it appears mid-to-late INCI. Higher-strength consumer-available “glycogen” serums/boosters and barrier-repair moisturizers can reach ~1–5% active glycogen (commonly supported by supplier guidance and the upper end of marketed claims), with usage above this becoming limited by viscosity/film feel, tack, and cost rather than regulatory caps (no specific EU/FDA maximum established for cosmetics). Rinse-off products generally sit toward the lower end due to short contact time, while the highest levels are observed in leave-on formulations.