Linalool is a naturally derived ingredient that is added to cosmetics and personal care products as a fragrance due to its pleasant floral smell.
Linalool refers to two enantiomers of a naturally occurring terpene alcohol found in a wide variety of flowers and spice plants. Terpenes are a large and diverse class of organic compounds produced by a variety of plants. They often have a strong scent and may protect the plants that produce them by deterring herbivores and by attracting predators and parasites of herbivores.
An enantiomer, also called an isomer, refers to a chiral molecule that is non-superimposable on its mirror image. R-linalool is also known as licareol and produces a woody and lavender-like scent. S-linalool is also known as coriandrol and produces a sweet, floral scent. Both enantiomeric forms are found in nature. Linalool can also be produced synthetically.
Over 200 species of plants produce linalool, mainly from the families Lamiaceae (mint and other herbs), Lauraceae (laurels, cinnamon, rosewood), and Rutaceae (citrus fruits).
Linalool functions as a fragrance ingredient in cosmetics and personal care products. In fact, linalool is used as a scent in 60% to 80% of perfumed hygiene products and cleaning agents including soaps, detergents, shampoos, and lotions, according to Medical News Today.
Linalool is also found in many essential oils, which have therapeutic claims including anti-anxiety, sedative, and anti-inflammatory effects. In a study investigating the anti-anxiety effects, rats that were injected with linalool showed a significant decrease in muscular activity when compared with rats that were not. While this study did not prove anti-anxiety effects, the results did suggest that linalool may help with sedation and muscle relaxation.
Linalool may also have anti-inflammatory properties. A 2002 study published in the scholarly journal Phytomedicine examined the anti-inflammatory activity of linalool, as well as linalyl acetate, the acetate ester of linalool. The study found that both linalool and linalyl acetate play a major role in the anti-inflammatory activity displayed by the essential oils containing them, and provide further evidence suggesting that linalool and linalyl acetate-producing species are potentially anti-inflammatory agents.
Of note, linalool can only act as an anti-inflammatory agent in its natural form and not when it is synthetically produced. Dr. Joshua Axe suggests to watch out for “linalool” on product labels. When this ingredient is listed in this form on the label, it is likely a synthetic, man-made version, not the natural compound part of a more complex organic essential oil. According to the National Academy of Sciences, about 95 percent of chemicals used in synthetic fragrances are derived from petroleum. There is a method in which linalool can be synthetically produced from petroleum.
In addition to use as a fragrance, linalool can be used a method of pest control against fleas, fruit flies, cockroaches, moths, and mosquitos. However, the EPA notes that “a preliminary screen of labels for products containing linalool (as the sole active ingredient) indicates that efficacy data on file with the Agency may not support certain claims to repel mosquitos.”
The Food and Drug Administration (FDA) includes linalool on its list of substances considered Generally Recognized As Safe (GRAS) as flavoring substance.
The safety of Linalool has been evaluated by the Research Institute for Fragrance Materials Expert Panel (REXPAN). Based on this evaluation, an International Fragrance Association (IFRA) Standard has been established. The IFRA Standard restricts the use of linalool in fragrances because of potential sensitization.
Unfortunately, linalool can be a problematic ingredient for some people. When linalool comes into contact with oxygen, it breaks down and becomes oxidized, which can cause an allergic reaction. Manufacturers do include other substances in the products to delay this oxidation process, but allergenic substances can still be formed from linalool when it is stored.
Dermatologist Johanna Bråred Christensson explains, “One way of trying to minimize exposure to oxidized linalool is to avoid buying large packs of soap and shower cream, and always to replace the top after using a bottle.”
In conclusion, the safety of linalool depends on whether this ingredient is used in its natural form or as a synthetic fragrance. Linalool as a natural compound of an organic essential oil may provide anti-inflammatory effects, but the synthetic version can possibly lead to skin irritation or allergic reactions.
References: Wikipedia, “Linalool”, Wikipedia, “Terpene”, Cosmetics Info, “Linalool”, Medical News Today, “Widely Used Fragrance Ingredients In Shampoos And Conditioners Are Frequent Causes Of Eczema”, 2009, Naturally Free Life, “Why Essential Oils Work: The Chemistry of Linalool”, 2016, AANA J. 2008 Feb;76(1):47-52, Phytomedicine. 2002 Dec;9(8):721-6, Dr. Axe, “Dangers of Synthetic Scents Include Cancer, Asthma, Kidney Damage and More”.