Monday, September 5, 2011

Tea Tree Oil (TTO)

Tea Tree.
Copyright Steven Foster
Alternate names: Australian tea tree oil, tea tree essential oil, melaleuca oil
Latin name: Maleleuca alternifolia

Summary: Tea tree oil has been shown to have some antibacterial and antifungal properties in vitro and in small in vivo studies.  It may prove useful for disinfecting wounds, and as an alternative to traditional antiseptic soaps used in the hospital setting.  Small studies have shown it useful as an antifungal.  More clinical studies need to be done to solidify the effectiveness and safety of TTO as a topical treatment.

Acne: A 5% tea tree oil water-based gel has been shown to be comparable to 5% benzoyl peroxide in the treatment of acne with fewer side effects.

Nail Fungus: 100% tea tree oil shows promise as a treatment for toe nail fungus and was as effective as 1% clotrimazole.

Fungal infection: A 10% tea tree oil cream might be effective in alleviating the symptoms of a fungal skin infection, however it was not shown to be effective in eradicating the fungus completely.

MRSA, E. coli, etc: In vitro and in vivo studies have demonstrated tea tree oil's effectiveness at eliminating a variety of bacteria, and promoting wound healing in people with MRSA.  It also shows promise as an alternative antiseptic in hand wash, and does not appear to confer resistance, even in bacterial strains prone to acquiring resistance.

Yeast: Tea tree oil may be an effective topical treatment for Candida infections, including albicans and non-albicans.  It has also been shown to be effective against Malassezia furur.

Seborrheic Dermatitis: Anecdote suggests that 5% tea tree oil might be effective in reducing dandruff, redness, and itching associated with seborrheic dermatitis.  I could not find any scientific studies supporting this, however I personally have used 5% TTO applied for 10 minutes once a week to treat my husband's seborrheic dermatitis with success.  It caused some redness and irritation shortly after application, however by the next day my husband reported a decrease in itching and redness that lasted for several weeks.

Warnings: Tea tree oil is for topical use only and should not be ingested.  Ingestion can result in confusion, drowsiness, rash, disorientation, and loss of muscle control in the arms and legs.
Tea tree oil should be used with caution in prepubescent boys as it might cause the reversible development of breast tissue.  It has been shown experimentally to cause small increases in estrogen levels and a small decrease in androgen levels.
Small studies have been conducted in humans to determine the appropriate topical dosage for tea tree oil.  In general, dosages of 1% and 5% have resulted in no adverse events, while dosages of 25% have been shown to cause allergic reactions in some individuals.  

Scientific Babble:  Medicinal use of tea tree oil originated in Australia.  TTO has been suggested for dandruff, acne, athlete's foot, nail fungus, wounds, infections, lice, cold sores, and for antibacterial and antifungal treatments ("Tea Tree Oil").  In a study in Australia, a 5% topical solution of TTO was shown to be as effective as 5% topical benzoyl peroxide in the treatment of mild to moderate acne, although it took longer for the effects of the TTO treatment to be realized (Carson).  Both the benzoyl peroxide and TTO treatment resulted in a reduction in acne symptoms after 3 months of use.  However, the TTO  had fewer side effects (dryness, itching, burning, irritation) than the benzoyl peroxide (44% vs 73%).

In a study comparing the efficacy of tolnaftate (an antifungal) and a 10% tea tree oil cream in treating fungal dermatitis, both were found equally effective in alleviating symptoms, however tolnaftate was more effective in eliminating the fungal infection than TTO.  TTO was found as effective as placebo at resolving the fungal infection.  However, application of 100% TTO was found to be as effective as 1% clotrimazole cream in the treatment of nail fungus.  Both were equally efficient at alleviating symptoms and eradicating the fungus (Bedi).

A 2005 study comparing soft soap and 5% tea tree oil in hand washing soap, antiseptic hand wash soap, and 1% Tween 80 found the TTO combined with antiseptic hand wash soap and Tween 80 to be acceptably effective at eliminating E. coli to be used in a health care setting (Messager).  TTO has been shown to inhibit a variety of bacteria including antibiotic resistant strains (e.g. MRSA, vancomycin-resistant enterococci), C. albicans and M. furfur at concentrations below 1% (Carson, Hammer).  In addition, TTO demonstrates higher effectiveness against transient bacteria as opposed to the bacteria that naturally colonize the skin (Carson). It has the added benefit over traditional antiseptics of being less likely to result in dermatological problems from over use, such as dried, cracked skin, even when added to an antiseptic soap (Messager).  In a study comparing traditional treatment for MRSA decolonization and TTO, there was no significant overall difference found between the traditional regimen and the TTO regimen.  However, the traditional treatment of Mupriocin at decolonizing nasal passages was found more effective than the 10% TTO cream.  The traditional body wash for the decolonization of superficial skin sites and lesions was found less effective than a 5% TTO body wash (Dryden).  A small 2011 study examining healing of wounds colonized by MRSA without signs of infection in the wound found that a majority (8 of 11) of wounds washed with a 3.3% TTO solution decreased in size over the course of the study, many with only short-term exposure.  It did not, however, cause MRSA decolonization of the wounds (Edmondson).  A larger study is needed to confirm the possibility of using TTO as a bacterial decolonization agent and treatment for wound healing.

A study in the New England Journal of Medicine reported three cases of otherwise unexplained prepubescent gynecomastia (breast development in boys) determined to have been caused by various topical products containing lavender oil or a combination of lavender oil and tea tree oil.  In vitro experiments showed that both lavender oil and TTO independently caused a slight increase in estrogen and a decrease in androgens.  In all three cases of prepubescent gynecomastia, hormone levels and sexual development were otherwise normal.  In one instance, an identical twin who was using the same lavender oil-containing products with the exception of a lavender soap did not develop gynecomastia.  Discontinuation of the topical products caused the breast tissue to regress and resolve after several months (Henley).

Topical dosages: three small studies have shown no adverse reactions with the use of 1% and 5% dermal tea tree oil patches.  However, a study of 28 individuals in which a 25% dermal TTO patch was applied resulted in severe allergic reactions in 3 individuals attributed to TTO.  The other 25 individuals completed the study without any adverse effects (Carson).  

I am not a doctor, nor do I attempt to feign one on the internet.  Please consult your personal doctor or healthcare provider before starting any treatment regimen to determine what will be the best treatment for you, your child, or some other person for whom you are making medical decisions.  Please inform your healthcare provider of any treatments you are taking, including those that fall under the umbrella of complementary and alternative medicine (they are still important).  This article is meant to provide a summary of the information I was able to find in scholarly journals on an complementary or alternative medicine to promote more informed conversations about alternative medicines between healthcare providers and patients.  This is not all inclusive.  Please consult the National Center for Complementary and Alternative Medicine for more information.


Bassett, I. B., D. L. Pannowitz, and R. S. Barnetson. "A Comparative Study of Tea-tree Oil versus Benzoylperoxide in the Treatment of Acne." Med J Aust 153.8 (1998): 455-58. PubMed. Web. 3 Sept. 2011. <>.

Bedi, M. K. "Herbal Therapy in Dermatology." Archives of Dermatology 138.2 (2002): 232-42. Archives of Dermatology. American Medical Association. Web. 3 Sept. 2011. <>.

Carson, C.F., T.V. Riley, and B.D. Cookson. "Efficacy and Safety of Tea Tree Oil as a Topical Antimicrobial Agent." Journal of Hospital Infection 40.3 (1998): 175-78.ScienceDirect. Web. 4 Sept. 2011. <>.

Dryden, M. S., S. Dailly, and M. Crouch. "A Randomized, Controlled Trial of Tea Tree Topical Preparations versus a Standard Topical Regimen for the Clearance of MRSA Colonization." Journal of Hospital Infection 56.4 (2004): 283-86. ScienceDirect. Web. 4 Sept. 2011. <>.

Edmondson, Margaret, Nelly Newall, Keryln Carville, Joanna Smith, Thomas V. Riley, and Christine F. Carson. "Uncontrolled, Open-label, Pilot Study of Tea Tree (Melaleuca Alternifolia) Oil Solution in the Decolonisation of Methicillin-resistant Staphylococcus Aureus Positive Wounds and Its Influence on Wound Healing." International Would Journal 8.4 (2011): 375-84. Wiley. Web. 4 Sept. 2011. <>.

Hammer, Katherine A., Christine F. Carson, and Thomas V. Riley. "Frequencies of Resistance to Melaleuca Alternifolia (tea Tree) Oil and Rifampicin in Staphylococcus Aureus, Staphylococcus Epidermidis and Enterococcus Faecalis." International Journal of Antimicrobial Agents 32.2 (2008): 170-73. ScienceDirect. Web. 4 Sept. 2011. <>.

---. "In-vitro Activity of Essential Oils, in Particular Melaleuca Alternifolia (tea Tree) Oil and Tea Tree Oil Products, against Candida Spp." Journal of Antimicrobial Chemotherapy 42.5 (1998): 591-95.Journal of Antimicrobial Chemotherapy. Oxford Journals. Web. 3 Sept. 2011. <>.

Henley, Derek V., Natasha Lipson, Kenneth S. Korach, and Clifford A. Bloch. "Prepubertal Gynecomastia Linked to Lavendar and Tea Tree Oils." New England Journal of Medicine 356.5 (2007): 479-86. Prepubertal Gynecomastia Linked to Lavendar and Tea Tree Oils. New England Journal of Medicine, 1 Feb. 2007. Web. 3 Sept. 2011. <>.

Kwieciński, Jakub, Sigrun Eick, and Kinga Wójcik. "Effects of Tea Tree (Melaleuca Alternifolia) Oil on Staphylococcus Aureus in Biofilms and Stationary Growth Phase."International Journal of Antimicrobial Agents 33.4 (2009): 343-47.ScienceDirect. Web. 4 Sept. 2011. <>

Messager, S., K.A. Hammer, C.F. Carson, and T.V. Riley. "Effectiveness of Hand-cleansing Formulations Containing Tea Tree Oil Assessed Ex Vivo on Human Skin and in Vivo with Volunteers Using European Standard EN 1499." Journal of Hospital Infection59.3 (2005): 220-28. ScienceDirect. Web. 4 Sept. 2011. <>.

"Tea Tree Oil -- Uses, Side Effects, Research." NCCAM. 19 April 2011.  NCCAM, NIH. 3 Sept 2011. <>.

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