Undecylenic acid is an organic

Organic compound

An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...

 unsaturated

Saturation (chemistry)

In chemistry, saturation has six different meanings, all based on reaching a maximum capacity...

 fatty acid

Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid with a long unbranched aliphatic tail , which is either saturated or unsaturated. Most naturally occurring fatty acids have a chain of an even number of carbon atoms, from 4 to 28. Fatty acids are usually derived from...

 derived from castor oil

Castor oil

Castor oil is a vegetable oil obtained from the castor bean . Castor oil is a colorless to very pale yellow liquid with mild or no odor or taste. Its boiling point is and its density is 961 kg/m3...

. It is the common name of the 10-undecenoic acid, (CH₂CH(CH₂)₈COOH). It is used in the manufacture of pharmaceuticals, cosmetics

Cosmetics

Cosmetics are substances used to enhance the appearance or odor of the human body. Cosmetics include skin-care creams, lotions, powders, perfumes, lipsticks, fingernail and toe nail polish, eye and facial makeup, towelettes, permanent waves, colored contact lenses, hair colors, hair sprays and...

 and perfumery, including antidandruff shampoos, antimicrobial powders and as a musk in perfumes and aromas. Undecylenic acid is produced by cracking

Cracking (chemistry)

In petroleum geology and chemistry, cracking is the process whereby complex organic molecules such as kerogens or heavy hydrocarbons are broken down into simpler molecules such as light hydrocarbons, by the breaking of carbon-carbon bonds in the precursors. The rate of cracking and the end products...

 of castor oil under pressure.

Medicinal uses

Undecylenic acid is a natural fungicide and is FDA approved in over-the-counter medications for skin disorders. It is the active ingredient in medications for skin infections, and relieves itching, burning, and irritation. For example, it is used against fungal skin infections

Mycosis

A mycosis is a fungal infection of animals, including humans. Mycoses are common, and a variety of environmental and physiological conditions can contribute to the development of fungal diseases...

, such as athlete's foot

Athlete's foot

Athlete's foot is a fungal infection of the skin that causes scaling, flaking, and itch of affected areas. It is caused by fungi in the genus Trichophyton and is typically transmitted in moist areas where people walk barefoot, such as showers or bathhouses...

, ringworm, jock itch or Candida albicans

Candida albicans

Candida albicans is a diploid fungus that grows both as yeast and filamentous cells and a causal agent of opportunistic oral and genital infections in humans. Systemic fungal infections including those by C...

. When used for jock itch, it can result in extreme burning, as the skin is rather sensitive.
It is also used in the treatment of psoriasis

Psoriasis

Psoriasis is an autoimmune disease that appears on the skin. It occurs when the immune system mistakes the skin cells as a pathogen, and sends out faulty signals that speed up the growth cycle of skin cells. Psoriasis is not contagious. However, psoriasis has been linked to an increased risk of...

.
Undecylenic acid has antiviral properties that are effective on skin infections such as herpes simplex

Herpes simplex

Herpes simplex is a viral disease caused by both Herpes simplex virus type 1 and type 2 . Infection with the herpes virus is categorized into one of several distinct disorders based on the site of infection. Oral herpes, the visible symptoms of which are colloquially called cold sores or fever...

.

The mechanism of action is unknown.

Other uses

Undecylenic acid can be used in silicon-based biosensors. Monolayers can be made on bare silicon transducer surfaces with the help of covalent bonds between silicon atom and the double bonds of undecylenic acid. The carboxylic acid

Carboxylic acid

Carboxylic acids are organic acids characterized by the presence of at least one carboxyl group. The general formula of a carboxylic acid is R-COOH, where R is some monovalent functional group...

 groups remain available for the conjugation of biomolecules such as DNA or proteins.