Stearalkonium Hectorite

Stearalkonium hectorite is a rheology modifier/thickener (organoclay) used at low concentrations (typically ~0.5–5%) to stabilize and gel oils, and it is generally non-reactive on skin. Clinical and consumer-use experience show low rates of irritation compared with surfactants, acids, or fragranced components, though very reactive or barrier-impaired patients can still experience mild stinging from the formulation matrix. Given its low inherent irritancy but non-zero risk in compromised-skin populations, it best fits a very gentle score. Safety Notes: Stearalkonium hectorite is a clay-based rheology modifier/suspending agent most often seen at very low levels (~0.05–0.5%) in leave-on emulsions (creams/lotions) to improve body and reduce pigment settling. Higher levels are observed in anhydrous or low-water systems (color cosmetics, sunscreen sticks, balms, and some oil/gel-serums) where it forms organoclay gels with polar activators; these can reach ~3–8% in high-structure consumer products for thickening and suspension. It is not subject to a specific EU/FDA maximum concentration limit as used, so the upper end is primarily constrained by sensory, clarity, and processability rather than regulation.