What Is It?

Trihydroxystearin is the triester of glycerin and hydroxystearic acid. In cosmetics and personal care products, Trihydroxystearin is used in the formulation of body, hand and skin care preparations. It is also used in makeup preparations including eye makeup, blushers, face powders, foundations and lipstick.

Why Is It Used?

Trihydroxystearin increases the thickness of the lipid (oil) portion of cosmetics products. When used in skin care formulations, it slows the loss of water from the skin by forming a barrier on the skin’s surface.

Scientific Facts

Trihydroxystearin is derived from the fatty acid, Hydroxystearic Acid. One method of producing both Trihydroxystearin and hydroxystearic acid involves the catalytic hydrogenation of castor oil.

Safety Information

The Food and Drug Administration (FDA) has reviewed the safety of Castor Oil, hydrogenated trihydroxystearin and approved its use as an indirect food additive for certain adjuvants and production aids. Trihydroxystearin has also been used as a thickening agent for peanut butter. The safety of Trihydroxystearin has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data, including study summaries from CIR Safety Assessments of Hydroxystearic Acid and Glyceryl Stearate and Glyceryl Stearate SE, and concluded that Trihydroxystearin was safe as used in cosmetic formulations.

CIR Safety Review: The CIR Expert Panel had previously conducted a safety assessment of Glyceryl Stearate and Hydroxystearic Acid and relied on data available from these reports because these two ingredients were chemically similar to Trihydroxystearin. When tested at concentrations up to 20.0%, Glyceryl Stearate was neither an irritant nor a sensitizer. Thus, in the absence of sensitization data on Trihydroxystearin, it was concluded that this ingredient was not likely a sensitizer based on data on a chemically similar ingredient. All of the available data suggested that Trihydroxystearin and its component chemical species were safe as used in cosmetic formulations.

FDA: Link to Code of Federal Regulations for Castor Oil, Hydrogenated…

Trihydroxystearin may be used in cosmetic and personal care products marketed in Europe according to the general provisions of the Cosmetics Regulation of the European Union. Ingredients of animal origin must comply with European Union animal by-products regulations.

Link to the EU Cosmetic Regulation:…

More Scientific Information

Trihydroxystearin is the triester of glycerin and hydroxystearic acid and is used as a skin conditioning agent, solvent, and viscosity increasing agent (nonaqueous) in cosmetics. Nonaqueous viscosity-increasing ingredients are used to thicken the lipid portions of cosmetic products. Their performance is the result of their water insolubility and compatibility with various lipids. They are widely used to thicken or gel various types of oleaginous products, such as lipsticks and pastes.


Find out more about the regulation of Food Additives by the Food and Drug Administration

Food Ingredients and Packaging:

Food Contact Substances:…

Substances Generally Recognized As Safe (GRAS):

Search the Code of Federal Regulations

EU Cosmetics Inventory