Raffinose

Raffinose is a non-ionic oligosaccharide used mainly as a humectant/skin-protective sugar at low percentages, and sugars of this class are generally well tolerated in leave-on products. It is not a pH-dependent active and lacks the protein-reactive chemistry typical of common irritants, so irritation risk is low, though very reactive or eczematous skin can still sting with high-osmolality humectant systems or compromised barriers. Given its typical use and low sensitization profile, it fits a very gentle (but not inert) rating. Safety Notes: In commercial skincare, raffinose is most often used as a minor humectant/prebiotic-style sugar or as part of a multi-sugar osmolyte blend, where it commonly appears at trace-to-low levels (~0.01–0.3%) in leave-on serums/creams and occasionally rinse-off cleansers. Higher-strength consumer products (especially “prebiotic/moisture complex” leave-on formulas and some sheet-mask essences) can push total raffinose to around 1–3%, with the upper end (~5%) observed in specialized OTC hydration/barrier-support formulations where tackiness and microbial control are managed with system design. There are no specific FDA/EU cosmetic concentration caps for raffinose; practical limits are driven by sensory/stability (stickiness, crystallization risk at high solids) and preservative robustness.