Linalool (Linalol) is a natural component found in essential oils such as lavender (1), rose, coriander, orange etc.It is also found in common fruits and vegetables.
In its purest form it is used in medicine as a bioactive anti-tumor principle (2)
It is commonly used as a fragrance in the cosmetic field to perfume the products that contain it.It can be obtained from laurel, bergamot, geranium and many other flowers.In these cosmetic applications, as the linalool is easily oxidizable when in contact with air, there is a risk of skin allergy (3).
Reading many texts and reviews in cosmetic head, the linalool is cited as a dangerous component, but it does not.It is the oxidation of the product that can be potentially dangerous, as the linalool is treated in a non-sterile manner and in contact with components that can accelerate the oxidation process. It is however a component that can cause contact allergy.
It has anti-stress properties (4).
Safety
Linalool and D-limonene are common fragrance ingredients that readily oxidize on exposure to air. The resulting hydroperoxides of linalool and D-limonene have been shown to have high frequencies of positive patch test reactions in several European and international studies....In this study, the frequency of positive patch test reactions to the hydroperoxides of linalool is 20% (19/96), and the frequency of positive reactions to the hydroperoxides of D-limonene is 8% (7/90). These high frequencies suggest that patch testing to the hydroperoxides of linalool and limonene should be performed in all patients with suspected fragrance allergy (5).
It is also used as an antiparasitic.
References______________________________________________________________________
(1) Adaszyńska M, Swarcewicz M, Dzięcioł M, Dobrowolska A. Comparison of chemical composition and antibacterial activity of lavender varieties from Poland. Nat Prod Res. 2013;27(16):1497-501. doi: 10.1080/14786419.2012.724408. Epub 2012 Sep 19.
Abstract. The aim of the study was comparing the chemical composition of the essential oils from five varieties of lavender (Lavandula angustifolia L.), and its biological activity against two pathogenic bacteria, Staphylococcus aureus and Pseudomonas aeruginosa. In the comparison we included the following varieties: 'Munstead', 'Munstead Strain', 'Lavender Lady', 'Ellegance Purple' and 'Blue River'. Selected varieties of lavender (L. angustifolia) are characterised by exactly the same main compounds with only variations in the percentage of content. The primary components of the essential oils were: linalool (23.9-15.8%), linalyl anthranilate (12.3-1.6%), 1-terpinen-4-ol (9.7-5.5%), p-menth-1-en-8-ol (7.9-4.0%) and linalool oxide (4.7-1.1%). From the essential oils that were tested, the 'Blue River' and 'Munstead' varieties have the greatest antibacterial activity against S. aureus and P. aeruginosa.
(2) Chang MY, Shen YL. Linalool exhibits cytotoxic effects by activating antitumor immunity. Molecules. 2014 May 22;19(5):6694-706. doi: 10.3390/molecules19056694.
Abstract. According to recent studies, the Plantaginaceae, which are traditional Chinese herbal remedies, have potential for use in viral infection treatment and cancer therapy. Linalool and p-coumaric acid are two of the biologically active compounds that can be isolated from the Plantaginaceae. This study mainly focused on investigating the bioactivity of linalool as well as the bioactivity of p-coumaric acid in terms of their cytotoxic effects on cancer cells. Whether the mechanisms of such effects are generated through apoptosis and immunoregulatory activity were also investigated. By using WST-1 analysis, it was shown that linalool and p-coumaric acid have good inhibitory effects against breast, colorectal and liver cancer cells. The IC50 values of linalool for those cancer cell types were 224 μM, 222 μM, and 290 μM, respectively, and the IC50 values of p-coumaric acid were 693 μM, 215 μM and 87 μM, respectively. Cell cycle analysis also confirmed that linalool and p-coumaric acid can lead to apoptosis. By using flow cytometry, it was determined that treatment with linalool rather than p-coumaric acid significantly increased the sub-G1 phase and that there were more cells concentrated in the G1 phase. Furthermore, by using cytokine array analysis, we found that linalool can stimulate IFN-γ, IL-13, IL-2, IL-21, IL-21R, IL-4, IL-6sR and TNF-α secretion. This demonstrated that in addition to the bidirectional regulation capabilities found in linalool, it also induces Th1 cellular immune response in T-47D cells. These results showed that linalool holds great potential for use in cancer therapy, and we believe that it could provide an alternative way to take action against tumors.
Cherng JM, Shieh DE, Chiang W, Chang MY, Chiang LC. Chemopreventive effects of minor dietary constituents in common foods on human cancer cells. Biosci Biotechnol Biochem. 2007 Jun
Abstract. Epidemiological evidence has suggested that vegetables and fruits may have a role in cancer prevention. The aim of the present study was to examine the anti-proliferative activity of ten related pure compounds from common vegetables and fruits. Studies were conducted on a series of carcinoma cells derived from eight human organs. The results show that linalool possessed the strongest activity against nine carcinoma cells, and that baicalein and luteolin also exhibited a broad spectrum of anti-proliferative activities. Among them, linalool showed the strongest activity against carcinoma of the cervix (IC50: 0.37 microg/ml), stomach (IC50: 14.1 microg/ml), skin (IC50: 14.9 microg/ml), lung (IC50: 21.5 microg/ml) and bone (IC50: 21.7 microg/ml). As for the flavonoids, luteolin exhibited the strongest activity against carcinoma of the stomach (IC50: 7.1 microg/ml), cervix (IC50: 7.7 microg/ml), lung (IC50: 11.7 microg/ml) and bladder (IC50: 19.5 microg/ml), whereas baicalein possessed the strongest anti-proliferative activity against carcinoma of the cervix (IC50: 9.8 microg/ml), stomach (IC50: 16.1 microg/ml) and skin (IC50: 19.5 microg/ml). The present study indicates that linalool possessed the strongest activity against a broad spectrum of carcinoma cells, especially cervical carcinoma cells, suggesting that linalool and flavonoids are partially responsible for the cancer prevention of common vegetables and fruits.
(3) Bråred Christensson J, Andersen KE, Bruze M, Johansen JD, Garcia-Bravo B, Gimenez Arnau A, Goh CL, Nixon R, White IR. Air-oxidized linalool: a frequent cause of fragrance contact allergy. Contact Dermatitis. 2012 Nov;67(5):247-59. doi: 10.1111/j.1600-0536.2012.02134.x.
Deza G, García-Bravo B, Silvestre JF, Pastor-Nieto MA, González-Pérez R, Heras-Mendaza F, Mercader P, Fernández-Redondo V, Niklasson B, Giménez-Arnau AM; GEIDAC. Contact sensitization to limonene and linalool hydroperoxides in Spain: a GEIDAC* prospective study. Contact Dermatitis. 2017 Feb;76(2):74-80. doi: 10.1111/cod.12714.
(4) Souto-Maior FN, de Carvalho FL, de Morais LC, Netto SM, de Sousa DP, de Almeida RN. Anxiolytic-like effects of inhaled linalool oxide in experimental mouse anxiety models. Pharmacol Biochem Behav. 2011 Dec;100(2):259-63. doi: 10.1016/j.pbb.2011.08.029.
Takahashi M, Satou T, Ohashi M, Hayashi S, Sadamoto K, Koike K. Interspecies comparison of chemical composition and anxiolytic-like effects of lavender oils upon inhalation. Nat Prod Commun. 2011 Nov;6(11):1769-74.
Abstract. Essential oils have traditionally been used for decades to alleviate the symptoms of various mental problems. In terms of anxiolytic-like properties, lavender oil is probably the most commonly used and best-studied essential oil. Although there is compositional variance among the oils extracted from different origins, there have been few studies performed to date to investigate how these differences affect the expression of anxiolytic-like activity. This paper discusses the interspecies differences and contributions of the main constituents in the expression of anxiolytic-like effects upon inhalation, as assessed in mice by the elevated-plus maze test, by comparing the essential oils from six different species of Lavandula. The results showed qualitative and quantitative variations in the tested oils, which results in significant differences in their anxiolytic-like activities. Our findings also suggest that linalyl acetate (LA) works synergistically with linalool (LO) and that the presence of both LA and LO is essential for the whole oil to work as an inhaled anti-anxiety agent.
(5) Nath NS, Liu B, Green C, Atwater AR. Contact Allergy to Hydroperoxides of Linalool and D-Limonene in a US Population. Dermatitis. 2017 Sep/Oct;28(5):313-316. doi: 10.1097/DER.0000000000000318.
Abstract. Background: Linalool and D-limonene are common fragrance ingredients that readily oxidize on exposure to air. The resulting hydroperoxides of linalool and D-limonene have been shown to have high frequencies of positive patch test reactions in several European and international studies....Conclusions: In this study, the frequency of positive patch test reactions to the hydroperoxides of linalool is 20% (19/96), and the frequency of positive reactions to the hydroperoxides of D-limonene is 8% (7/90). These high frequencies suggest that patch testing to the hydroperoxides of linalool and limonene should be performed in all patients with suspected fragrance allergy.
Linalool 
