Isostearic Acid

What Is It?

Isostearic Acid is a clear, oily liquid that is used in a wide variety of cosmetics and personal care products.

Why Is It Used?

Isostearic Acid functions as a surfactant – cleansing agent, and a binder.

Scientific Facts

Isostearic Acid, a fatty acid, is a blend of different forms of octadecanoic acid, which is obtained from animal and vegetable fats and oils. Isostearic Acid can be prepared from many sources including soybean oil or tallow

Safety Information

The safety of Isostearic Acid has been assessed by the Cosmetic Ingredient Review (CIR) Expert Panel. The CIR Expert Panel evaluated the scientific data and concluded that Isostearic Acid was safe as a cosmetic ingredient in the present practices of use. In 2002, the CIR Expert Panel considered available new data on Isostearic Acid and reaffirmed the above conclusion.

CIR Safety Review: In clinical studies, no signs of irritation were observed with undiluted Isostearic Acid. Isostearic Acid was neither an irritant nor a sensitizer and gave no indication of phototoxicity. Although there was some evidence that Isostearic Acid may contribute to the formation of comedones (acne-like skin bumps), the CIR Expert Pane noted that availabe tests were not adequate to predict the potential for human comedogenicity.

Based on the available data, the CIR Expert Panel concluded that Isostearic Acid was safe as a cosmetic ingredient in the present practics of use. When made from plants, Isostearic Acid may be used in cosmetics 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 the European Union animal by-products regulations.

Link to the EU Cosmetic Regulation:…

More Scientific Information

Isostearic Acid is a mixture of branched chain 18 carbon aliphatic acids consisting mainly of methyl branched isomers of octadecanoic acid. Isostearic Acid shows some of the same chemical properties as stearic acid and has physical properties similar to those of oleic acid.