Tea tree oil is one of the most known oils in aromatherapy due to its therapeutic properties in treating several skin diseases. However, it also has the most published allergic reactions among all the essential oils (De Groot & Schmidt E., 2016) This may cause fear among patients and ask whether tea tree oil can be faithful in proving its efficacy in healing their illnesses. We aim to find honest and sincere answers in addressing this question, hence we looked at different research to understand what triggers the adverse effects when using tea tree oil.
In this post, two possible causes are listed as to why tea tree oil may elicit some side effects when applied topically.
1. Oxidized tea tree oil
41 cases were identified to have positive reactions to tea tree oil among the 2320 patches tested at the Skin and Cancer Foundation Victoria over 4.5 years. 66% or 27 of 41 have claimed that they used tea tree oil while 20% or 8 of 41 have reported having used neat tea tree oil. This 2007 retrospective review conducted by Rutherford et al. showed that freshly opened tea tree oil yields no or weak reaction.
Meanwhile, a 1997 study presented by Fritz et al. reported that 7 patients had allergic contact dermatitis after using products containing tea tree oil. The result of their study has led them to the conclusion that photo-aged tea tree oil is a stronger sensitizer.
To understand how photo-oxidation takes place and know what it does to tea tree oil, reviewing the study of Hausen et al. (1999) would be helpful. The researchers in this paper have exposed the tea tree oil to light, oxygen, and warmth by placing it on a windowsill. Storing tea tree oil in this way for a few days to months can lead to photo-oxidation which can result in the degradation of the quality of the oil. Oxidized tea tree oil then becomes a moderate to strong sensitizer as peroxides, epoxides, and endoperoxides, like ascaridol, and 1,2,4-trihydroxy methane are formed. These compounds are responsible for the development of allergic contact dermatitis (Hausen et al., 1999). This claim is supported by the 2014 research findings of Christoffers et al. who states in his paper that oxidized tea tree oil that contains compounds such as ascaridole may cause allergic contact dermatitis. Moreover, the 2006 study by Hammer and his colleagues is in agreement that oxidation of the tea tree oil leads to allergic reactions. Some research also reports consistent findings.
The research of De Groot and Schmidt, E. (2016), Ahmad et al. (2019), and the 2007 investigation of Rutherford et al. all agree that fresh tea tree oil has a weak sensitizing material. While oxidized tea tree oil becomes a sensitizer three times stronger (Hausen et Al., 1999) once oxidation takes place, its allergenic potency also increases (Ahmad et al. (2019). Hence, to preserve the quality of tea tree oil Hammer and his colleagues suggested in their 2006 paper that tea tree oil must be stored correctly.
2. Topical use of off-label, 50% concentration tea tree oil
A 2021 study by Tharmarajah and Coroneo reported that a 44-year-old man with a 1-year history of blepharitis had experienced bilateral ocular discomfort. After using topical, off-label 50% tea tree oil solution. The researchers advised to use of approved, low-concentration tea tree oil products when treating Demodex-related blepharitis.
This recommendation is in agreement with Hammer et al (2006) and Groot and Schmidt, E. (2016) statements. According to Hammer and, and his colleagues, using tea tree oil at higher concentrations may cause skin irritation, while Groot and Schmidt E. claimed that most allergic reactions are caused by the use of pure tea tree oil. Ergo, to ensure safety it is recommended to apply only diluted oil topically (Hammer et al., 2006)
Though there are studies that report some side effects in using tea tree oil, knowing and choosing the right tea tree oil, plus ensuring the quality of your tea tree oil, handling it with care, and protecting it from being exposed to factors that can cause oxidation will enable you to experience the therapeutic effects of tea tree oil.
Be committed and faithfully embrace best practices
References:
- (1) De Groot, A. C., & Schmidt, E. (2016). Tea tree oil: contact allergy and chemical composition. Contact dermatitis, 75(3), 129–143. https://doi.org/10.1111/cod.12591
- Rutherford, T., Nixon, R., Tam, M., & Tate, B. (2007). Allergy to tea tree oil: a retrospective review of 41 cases with positive patch tests over 4.5 years. The Australasian journal of dermatology, 48(2), 83–87. https://doi.org/10.1111/j.1440-0960.2007.00341.x
- Fritz, T. M., Burg, G., & Krasovec, M. (2001). Dermatitis de contact allergique aux cosmétiques à base de Melaleuca alternifolia (tea tree oil) [Allergic contact dermatitis to cosmetics containing Melaleuca alternifolia (tea tree oil)]. Annales de dermatologie et de venereology, 128(2), 123–126.
- Hausen, B. M., Reichling, J., & Harkenthal, M. (1999). Degradation products of monoterpenes are the sensitizing agents in tea tree oil. American journal of contact dermatitis: official journal of the American Contact Dermatitis Society, 10(2), 68–77. https://doi.org/10.1016/s1046-199x(99)90002-7
- Ahmad S., Afsana., Popli H. A review on efficacy and tolerability of tea tree oil for acne. Delhi Pharmaceutical Sciences and Research University. Vol 9 No 3 (2019): Volume 9, Issue 3, May June 2019
- Christoffers, W. A., Blömeke, B., Coenraads, P. J., & Schuttelaar, M. L. (2014). The optimal patch test concentration for ascaridole as a sensitizing component of tea tree oil. Contact dermatitis, 71(3), 129–137. https://doi.org/10.1111/cod.12199
- Hammer, K. A., Carson, C. F., Riley, T. V., & Nielsen, J. B. (2006). A review of the toxicity of Melaleuca alternifolia (tea tree) oil. Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association, 44(5), 616–625. https://doi.org/10.1016/j.fct.2005.09.001
- Tharmarajah, B., & Coroneo, M. T. (2021). Corneal Effects of Tea Tree Oil. Cornea, 40(10), 1363–1364. https://doi.org/10.1097/ICO.0000000000002776
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