Lavender’s adverse skin reactions
Despite popular belief about the innocuousness of botanical extracts such as lavender, there are numerous cases in the literature concerning contact dermatitis to lavender fragrance or lavender oil. A study of patch test results in Japan found that in the period from 1990-1998, the rate of positive patch tests to 20% lavender oil in petrolatum rose from 1.1% to 13.9%, an increase that correlated with the rising popularity of aromatherapy using lavender oil and the trend of placing dried lavender flowers in pillows, drawers, cabinets, or rooms. Since lavender is increasing in popularity as a fragrance, it is possible that more patients in the future will experience such reactions.
There is evidence that the contact allergencitiy of lavender oil is due to its lack of natural protection against autoxidation. When lavender oil is exposed to air, its chief components (linalyl acetate, linalool and b-caryophyllene) oxidize rapidly, forming hydroperoxides and other oxidation products that are potent contact allergens.
Research also indicates that other components of lavender, specifically linalool, can be cytotoxic, meaning that topical application causes skin-cell death (Source: Cell Proliferation, June 2004, pages 221–229). Lavender leaves contain camphor, which is known as a skin irritant. Because the fragrance constituents in lavender oil oxidize when exposed to air, lavender oil is pro-oxidant. This enhanced oxidation also increases its irritancy on skin (Source: Contact Dermatitis, September 2008, pages 143–150). Lavender oil is the most potent form, and even small amounts of it (0.25% or less) can be problematic.
Sköld M, Hagvall L, Karlberg AT. Autoxidation of linalyl acetate, the main component of lavender oil, creates potent contact allergens. Contact Dermatitis. (2008)
Hagvall L, et. al. Lavender oil lacks natural protection against autoxidation, forming strong contact allergens on air exposure. Contact Dermatitis. (2008)
Lavender as an antioxidant
The antioxidant power of lavender essential oil has been evaluated through the in vitro FRAP, ABTS and DPPH assays. It is severely diminished upon UVA irradiation due to the degradation of the oil constituents, but this can be mitigated by the addition of propolis. Source: Gismondi A, et. al. Biochemical composition and antioxidant properties of Lavandula angustifolia Miller essential oil are shielded by propolis against UV radiations. Photochem Photobiol. (2014) It should be noted that this source is from an in-vitro study.
“There is no research showing it has any benefit for skin” (Sources: Phytotherapy Research, June 2002, pages 301–308).
Lavender’s antimicrobial effects
The essential oils derived from several Lavandula species have demonstrated antibacterial and/or antifungal activities. It appears to be more effective than lemon oil, but less so than tea tree oil and thyme oil.
Lavender oil’s antimicrobial effect can be augmented through blending with other essential oils, such as cinnamon oil and orange oil.
Although personal care products frequently do not contain sufficiently high amounts of lavender oil for it to exert significant aseptic activity on its own, it can be used as a component of preservative systems to lower the concentration of synthetic preservatives required to pass antimicrobial effectiveness tests.
- Adaszyńska M, et. al. Comparison of chemical composition and antibacterial activity of lavender varieties from Poland. Nat Prod Res. (2013)
- Sienkiewicz M, et. al. Antibacterial activity of thyme and lavender essential oils. Med Chem. (2011)
- Zuzarte M, et. al. Lavandula luisieri essential oil as a source of antifungal drugs. Food Chem. (2012)
- Zuzarte M, et. al. Chemical composition and antifungal activity of the essential oils of Lavandula viridis L’Her. J Med Microbiol. (2011)
- Kirmizibekmez H, et. al. Chemical composition and antimicrobial activity of the essential oils of Lavandula stoechas L. ssp. stoechas growing wild in Turkey. Nat Prod Commun. (2009)
- Kunicka-Styczyńska A, Sikora M, Kalemba D. Lavender, tea tree and lemon oils as antimicrobials in washing liquids and soft body balms. Int J Cosmet Sci. (2011)
- de Rapper S, et. al. The In Vitro Antimicrobial Activity of Lavandula angustifolia Essential Oil in Combination with Other Aroma-Therapeutic Oils. Evid Based Complement Alternat Med. (2013)
- Sabara D, Kunicka-Styczynska A. Lavender oil – flavouring or active cosmetic ingredient? Food Chem Biotechnol. (2009)
- Kunicka-Styczyńska A, Sikora M, Kalemba D. Antimicrobial activity of lavender, tea tree and lemon oils in cosmetic preservative systems. J Appl Microbiol. (2009)
- Kunicka-Styczyńska A, et. al. Preservative activity of lavender hydrosols in moisturizing body gels. Lett Appl Microbiol. (2014)