Sorbitan Isostearate

Sorbitan isostearate is a nonionic emulsifier/surfactant typically used at low concentrations (about 0.5–5%) to stabilize creams and lotions, and it is generally well-tolerated in clinical and consumer use. However, as a surfactant/emulsifier it can contribute to barrier disruption or mild irritation in highly reactive or eczematous skin—especially in leave-on products used repeatedly—so it is best classified as gentle rather than exceptionally gentle. Safety Notes: Sorbitan isostearate is most often used as a W/O emulsifier/co-emulsifier or dispersant, and in many leave-on creams/lotions it appears at low levels (~0.1–1%) as part of an emulsifier system; the lowest observed uses in commercial products are around 0.05% as a minor stabilizer or pigment/UV filter wetting aid. High-strength consumer products such as water-in-oil sunscreens, heavy barrier creams, cleansing oils/balms, and some makeup/primer-type emulsions can use it at ~3–8% to build and stabilize the oil-phase structure; higher levels are uncommon due to sensory (waxy/drag) and emulsification balance constraints. No specific EU/FDA maximum applies for this ingredient in cosmetics beyond general safety, so the upper bound is driven by formulation performance and tolerability rather than regulation.