Linalool

Linalool is an acyclic monoterpene alcohol with the molecular formula C10H18O. Like many terpenes it is chiral and occurs as two mirror-image forms, sometimes called licareol and coriandrol, which have subtly different floral scents. It is a colorless, oily liquid with a soft, sweet aroma reminiscent of lavender and spice, and it is one of the most common fragrance molecules found in nature.

The compound is produced by hundreds of plant species across many families, and it is a major component of the essential oils of lavender, coriander, sweet basil, rosewood, bergamot, and citrus blossom, among others. It is also one of the notable aromatic terpenes present in cannabis. Because of its wide natural distribution and pleasant smell, it is manufactured on a large scale for commercial use.

Linalool is valued chiefly as a fragrance. It appears in a large share of perfumed goods, including perfumes, colognes, soaps, shampoos, detergents, and lotions, where it contributes floral top notes or rounds out other scents. It is also used as a flavoring in foods and beverages, and it has practical applications as an insect repellent and a component of some pesticides. In the United States it is recognized as generally safe for use as a synthetic flavoring.

Linalool is one of the compounds most often credited with the relaxing reputation of lavender aromatherapy, and it has been the subject of behavioral research. In laboratory studies, mice exposed to inhaled linalool showed reduced anxiety, greater social interaction, and less aggression, supporting the idea that lavender-type aromas can promote a calmer state ^[1]. Such effects are commonly linked to the brain's GABA system, the main inhibitory signaling network involved in relaxation and sedation ^[2]. This work is largely preclinical, and linalool is not an approved medicine; it is encountered mainly as a fragrance and flavor rather than a therapeutic drug.

Linalool is generally well tolerated, but like other fragrance terpenes it can cause problems on the skin, particularly after it has been exposed to air. Oxidation converts linalool into hydroperoxides that are far stronger sensitizers than the fresh compound, and patch testing has identified these oxidation products as an important cause of fragrance-related allergic contact dermatitis ^[3]. For this reason it is among the fragrance ingredients that must be declared on product labels in some regions. It can also irritate the eyes and airways at high concentrations.

Well tolerated as a food and fragrance component. Linalool can oxidize on air exposure into compounds that cause skin allergy, so old or oxidized oils are more sensitizing. High oral doses aren't well studied in humans.