Linoleic acid

Linoleic acid, also known as linolenic acid (from the Latin "linum" flax), is an unsaturated essential fatty acid with 18 carbon atoms, which belongs to the 2-omega-6 acids due to its second double bond.

Linoleic acid appears as a fatty, colorless, yellow oil that is easily soluble in organic solvents and insoluble in water.

Linoleic acid is found as a natural glyceride in linseed oil(Lini oleum virginale), hemp oil (Cannabis sativa), poppy seed oil (Papaver somniferum), sea buckthorn oil(Hippophae rhamnoides) but also in animal oils (e.g. whale fat). Grape seed oil and safflower oil have the highest linoleic acid content of all vegetable oils at 60-80%.

Salts of linoleic acid are called linoleates. Gylceryl linoleate (INCI) is used in cosmetics as an emollient and emulsifier.

The medical significance of linoleic acid, in particular for immunological defense mechanisms of the skin, still requires further investigation.

1. Fuke G et al (2016) Systematic evaluation on the effectiveness of conjugated linoleic acid in human health. Crit Rev Food Sci Nutr PubMed PMID: 27636835.
2. Nguyen MT et al.(2015) Skin-Specific Unsaturated Fatty Acids Boost the Staphylococcus aureus Innate Immune Response. Infect Immune 84:205-215.