Insect repellent activity
In a 2016 study by Gutiérrez et al., the essential oil of T. vulgaris was found to be effective against Pediculus humanus capitis (head lice) adults and eggs. The researchers concluded that T. vulgaris achieves a strong knockdown and mortality rate in adult head lice and toxicity in the eggs after 21 minutes of application at a low concentration.18
In a small 1999 study by Barnard of the repellency to Aedes aegypti and Anopheles albimanus of various concentrations and combinations of five essential oils (Bourbon geranium, cedarwood, clove, peppermint, and thyme) applied to human skin, thyme and clove oils were found to be the most effective mosquito repellents. The author noted that thyme oil (as well as clove and peppermint oils) can irritate the skin and the odor of thyme and clove oils, at concentrations of 25%, or more were deemed unacceptable by the two participants in the study.19
Three years later, Choi et al. found that the essential oil of T. vulgaris also repelled adult mosquitoes (Culex pipiens pallens) on hairless mice and displayed potent repellent activity.20
Melanoma
In 2005, Carrera et al. reported a case of long-term complete remission of cutaneous melanoma metastases in a 73-year-old white woman who consumed a dried thyme herbal tea and thyme topical applications in compresses.4 An association between thyme and melanoma has not been reported in the subsequent literature.
Conclusion
Thyme has a long history of culinary and medical uses. Its antimicrobial and antioxidant activity are well documented. While there is reason to consider the potential applications of thyme for dermatologic conditions, much more research is necessary to determine its viability for such purposes.
References
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16. Int J Dermatol. 2012 Jul;51(7):790-5.
17. J Cosmet Dermatol. 2013 Jun;12(2):116-22.
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19. J Med Entomol. 1999 Sep;36(5):625-9.
20. J Am Mosq Control Assoc. 2002 Dec;18(4):348-51.
Dr. Baumann is chief executive officer of the Baumann Cosmetic & Research Institute in the Design District in Miami. She founded the Cosmetic Dermatology Center at the University of Miami in 1997. Dr. Baumann wrote the textbook “Cosmetic Dermatology: Principles and Practice” (New York: McGraw-Hill, 2002), and a book for consumers, “The Skin Type Solution” (New York: Bantam Dell, 2006). Her latest book, “Cosmeceuticals and Cosmetic Ingredients,” was published in November 2014. Dr. Baumann has received funding for clinical grants from Allergan, Aveeno, Avon Products, Evolus, Galderma, GlaxoSmithKline, Kythera Biopharmaceuticals, Mary Kay, Medicis Pharmaceuticals, Neutrogena, Philosophy, Topix Pharmaceuticals, and Unilever. Dr. Baumann also developed and owns the Baumann Skin Type Solution skin typing systems and related products.