Undecylenic / Undecenoic Acid is an organic unsaturated fatty acid derived from natural castor oil. It is the common name of the undecenoic acid (CH2CH(CH2)8COOH). A white or pale yellow liquid, practically insoluble in water, freely soluble in alcohol and in fatty and essential oils. It is used in the manufacture of pharmaceuticals, cosmetics and perfumery including anti-dandruff shampoos, anti-microbial powders and as a musk in perfumes and aromas. Undecylenic acid is a natural fungicide and is FDA approved in over-the-counter medications for skin disorders or problems. It is the active ingredient in medications for skin infections, and relieves itching, burning, and irritation. Undecylenic Acid is commonly used in industrial fungicides and bactericides. It is also used as an intermediate in chemical synthesis, polyamide plastics and fibers, perfume bases and synthetic floors. Undecylenic acid topical (for the skin) is a fatty acid that works by preventing fungus from growing on the skin. Undecylenic acid topical is used to treat skin infections that are caused by fungus, such as athlete's foot, jock itch, diaper rash, prickly heat, excessive sweating in the groin area, itching, burning, and chafing. Undecylenic acid topical may also be used for other purposes not listed in this medication guide. Undecylenic Acid as well as some of its salts (Calcium, Zinc) are used in the formulation of topical antifungal products. In the United States, topical antifungal products are regulated as Over-the-Counter (OTC) drugs by the Food and Drug Administration. It is used as a surfacant with cleansing properties. It is used as a precursor in the manufacture of aromatic chemicals, polymers or modified silicones. Due to its bifunctional properties, undecylenate is also used as a linking molecule to conjugate other biomolecules such as proteins. It serves as an acid moiety for anabolic steroid boldenone.