Glyceryl Isostearate

Glyceryl isostearate is primarily an emollient/emulsifier used at low-to-moderate levels (often ~1–5%) to improve texture and reduce water loss, and it is generally well tolerated in rinse-off and leave-on products. Clinical and patch-test experience suggest a low rate of irritation or sensitization, but compromised barrier states (e.g., active eczema) can still react to lipidic surfactant-like emulsifiers, so it is not treated as fully inert. Overall, it fits a very gentle profile with minimal but non-zero irritation potential in highly reactive individuals. Safety Notes: Glyceryl isostearate is used as an emollient/co-emulsifier and pigment dispersant; in many commercial leave-on lotions, sunscreens, and makeup products it appears at low levels (~0.1–1%) as an auxiliary stabilizer or slip agent. In richer creams, cleansing balms, and anhydrous/oil-heavy sticks (including some makeup and high-slip barrier products), it can be a primary structuring emulsifier/emollient and is seen in the ~5–15% range in consumer-available formulations. There is no specific FDA/EU maximum concentration limit for this ingredient in cosmetics; the practical upper end is driven by texture/waxiness, phase behavior, and stability rather than regulation, with rinse-off products generally using the lower-to-mid portion of the range.