Definition
Sorbitan sesquioleate (SSO) is a water-in-oil emulsifier that allows oil and water to blend into a homogeneous mixture that does not separate. It is widely used in cosmetics such as moisturizers, cleansers, conditioners, eye makeup removers, exfoliating products, sunscreens, and baby products. Closely related emulsifiers such as Span 20 (sorbitan monolaurate), Span 40 (sorbitan monopalmitate), span 60 (sorbitan monostearate), span 65 (sorbitan tristearate), span 80 (sorbitan monooleate), and Span 85 (sorbitan trioleate) can cross-react with SSO. They, therefore, should be avoided in patients sensitive to SSO.
Safety
Sorbitan Sesquioleate is considered a low hazard ingredient by the Cosmetics Database, which only notes mild concerns regarding organ system and toxicity, due to animal studies that showed organ effects and skin moderation at moderate doses.
