Linoleic acid

Linoleic acid or linseed oil acid (from Latin "Linum" linseed), is an unsaturated essential fatty acid with 18 carbon atoms, which belongs to the 2-omega-6-acids because of its second double bonds.

Linoleic acid appears as a fatty, colorless, yellow oil that is highly 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 contain with 60-80% the highest amount of linoleic acid of all vegetable oils.

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

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

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.