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What is Tea Tree Oil & How Is It Used?

Dr. Kline & Green Team
16 October 2019
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The scientific name of tea tree oil is Melaleuca alternifolia, from the leaves of genus Melaleuca and species Alternifolia. Tea tree oil is composed of terpene hydrocarbons and alcohols, which are both volatile and aromatic (for example some people use it for aromatherapy).

While it is a popular natural remedy, and available over the counter in many places, tea tree oil is not inherently stable and is a volatile oil, meaning it has the ability to rapidly transition from a liquid state to a gas state. Its highly volatile nature means that special packaging precautions must be taken to avoid oxidation, which is a process in which atoms gradually lose electrons through a series of chemical reactions, leading to low-quality oil that emits a terrible odor and taste.

Users can slow the oxidation process, by storing tea tree oil bottles in tightly sealed containers in dark, cool rooms. For packaging and shipping, the following materials allow top-quality tea tree oil maintenance during all conditions: inert gas capping, level 5 fluorinated HDPE containers, Schutz EcoBulk MX 1000 Un Ex Evoh intermediate bulk containers (IBCs), or stainless steel, which is considered the best for transport.

Primary uses of Tea Tree Oil:

The earliest documented use of tree oil within the industrial medical field was in Australia during the 1920s, and tea tree oil use has since spread worldwide. Tea tree oil, nowadays, is used primarily for antimicrobial purposes and is only applied topically, due to the low threshold of oral toxicity effects. A low threshold indicates that the bodily tolerance for tea tree oil is extremely low without the presence of harmful side effects or possible fatality.

Tea tree oil also contains a low threshold for dermal toxicity effects and must be diluted to at least 10% within all formulations. When used for dermatological treatments such as skin conditions, skincare and beauty, tea tree oil is usually diluted in a carrier oil or water base. Tea tree oil is considered an essential oil, which are potent oils which go through a distillation process in which the liquid substance is heated and the remaining vapor is condensed. On the other hand, carrier oils are extracted from plant seeds through a manual process and are used to safely “carry” the essential oils through the skin layers without burning or other negative effects.

Potential side effects of Tea Tree Oil:

Drops of tea tree oil are usually safe to use in diluted, topical preparations. However, the following side effects may occur if it is not properly diluted or the individual has a tea tree oil sensitivity:

  • itchiness
  • stinging
  • burning
  • scaling
  • redness
  • dryness
  • skin irritation
  • dermatitis (allergic skin rash)

When consumed orally, tea tree oil can have the following toxic effects:

  • confusion
  • loss of muscle coordination
  • loss of consciousness

There is no evidence for clinical drug interactions with tea tree oil. Tea tree oil can be safely used alongside clinical formulations.

Antifungal effects:

While numerous clinical evaluations over tea tree oil’s effectiveness for onychomycosis (nail fungus) and other fungal infections have been conducted, none of these studies have been published. A large percent of studies have revealed that tea tree oil has the ability to alter membrane permeability of Candida Albicansyeast cells and create an antifungal effect which inhibits the formation of germ tubes. Since onychomycosis is primarily caused by this yeast, this finding may possibly lead to other fungal treatment findings and, in the near future, clinically significant results for the treatment of onychomycosis with tea tree oil.

Additional properties and resistance effects:

Tea tree oil is bactericidal, meaning that it ultimately destroys bacteria and this occurs through the disintegration of bacterial cell membranes. Antiprotozoal effects were seen with a 50% decrease in protozoal growth and antiviral effects with reduced viral infection in tobacco plants after only 10 days. Tea tree oil also has shown anti-inflammatory effects with the ability to reduce edema-swelling, erythema-flares, and histamine-induced inflammation.

*There is no evidence for the development of fungal or bacterial cross-resistance to tea tree oil. Numerous studies have failed to produce results showing microbial resistance to tea tree oil. This may be due to its biologically complex composition, which is abundant in natural and unprocessed substances.

Dosage and Toxicity levels:

Topical tea tree oil is not recommended for oral use; however, in rat models, a 50% lethal dose occurred within a range of 1.9 – 2.6 ml/kg. Tea tree oil lethal toxicity levels have not been tested in humans, of course, but human poisoning has occurred with full recovery.

For lowering the risk of dermal toxicity, it is widely recommended to use tea tree oil at a diluted dosage of 10% or less. During a patch-test study involving human participants, the results revealed dermal irritation at a mean score of 0.25, indicating that tea tree oil should never constitute 25% of a dilution formulation. Allergic reactions occur mostly due to oxidated oil from either natural age factors or a lack of proper storage precautions.

Concluding comments:

In regards to clinical efficacy, tea tree oil and variants such as tea tree oil gel is NOT a clinically-approved dermatological / medical topical application to be used for bacterial, fungal, or viral infections as there is not enough empirical data to back-up these sentiments. Overall, tea tree oil should be used with caution and make sure to always take the proper dilution measures (at least 10%). Tea tree oil should NEVER be consumed orally and is only recommended for topical application use with wounds, treatment of moderate acne, dandruff, head lice, symptoms of and cases of athlete’s foot, along with other sensitive skin ailments. Additional experiments and a further study of tea tree oil should be conducted to determine a significant clinical effect of tea tree oil on onychomycosis.

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These include various tea tree oil studies and information from the following.

  1. Carson, C. F., Hammer, K. A., & Riley, T. V. (2006). “Melaleuca alternifolia (tea tree) oil: a review of antimicrobial and other medicinal properties.” Clinical Microbiology Reviews 19(1), doi: 10.1128/CMR.19.1.50-62.2006
  2. NIH. (2017, Oct. 24). “Tea Tree Oil”. U.S. National Library of Medicine: National Center for Biotechnology Information, database: PubChem, Retrieved from: https://pubchem.ncbi.nlm.nih.gov/
  3. Australian Tea Tree Industry Association (2017, Feb. 13). “Australian tea tree oil: a natural treatment – nature’s best.” Retrieved from: https://teatree.org.au/
  4. Mayo Clinic Staff. (2017, Oct. 24). “Tea Tree Oil”. Mayo Clinic, Retrieved from: https://www.mayoclinic.org/

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