Zinc Undecylenate

Safety Information

U.S. Food and Drug Administration

The U.S. Food and Drug Administration (FDA) reviewed the safety of undecylenic acid and its calcium and zinc salts and approved these ingredients for use in over-The-counter (OTC) antifungal drug products.

Expert Panel for Cosmetic Ingredient Safety

The Expert Panel for Cosmetic Ingredient Safety has deferred evaluation of these ingredients because the safety has been assessed by FDA. This deferral of review is according to the provisions of the Expert Panel procedures.

In the U.S., OTC antifungal products may contain undecylenic acid, calcium undecylenate or zinc undecylenate, individually or in any ratio that provides a total undecylenate concentration of 10 to 25%.

Link to FDA Code of Federal Regulations for undecylenic acid

Undecylenic acid and its salts may be used as preservatives in cosmetics and personal care products marketed in Europe according to the Cosmetics Directive of the European Union (see Annex VI).

Link to the EU Cosmetic Regulation:


Zinc Undecylenate

What Is It?

Undecylenic acid, a fatty acid, occurs as a pale liquid. Undecylenic acid as well as some of its salts (calcium, zinc) are used in the formulation of topical antifungal products. In the U.S., topical antifungal products are regulated as OTC drugs by the FDA.

Why Is It Used?

Undecylenic acid inhibits the growth and reproduction of fungal cells and decrease the number of fungi present. In the U.S. antifungal agents are regulated as OTC drug ingredients. Undecylenic acid and its calcium and zinc salts also help to cleanse the skin or to prevent odor by destroying or inhibiting the growth of microorganisms and prevent powdered or granular substances from forming clumps. These ingredients also clean skin and hair by helping water to mix with oil and dirt so that they can be rinsed away, and help to form emulsions by reducing the surface tension of the substances to be emulsified.

Scientific Facts

Undecylenic acid is an organic unsaturated fatty acid derived from natural castor oil (ricinoleic acid). It is the common name of the 10-undecenoic acid and is used in the manufacture of pharmaceuticals and cosmetics and personal care products. Undecylenic acid is produced by cracking of castor oil under pressure.

10-Undecenoic acid is another name for undecylenic acid. It is a fatty acid. Fatty acids are the carboxylic acids obtained by hydrolysis of fats and oils. Carboxylic acids having alkyl chains shorter than about seven carbon atoms are not commonly considered fatty acids. Natural fatty acids may be saturated or unsaturated and generally contain an even number of carbon atoms.