Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.
For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.
3 StarsReliable and relatively consistent scientific data showing a substantial health benefit.
2 StarsContradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
1 StarFor an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.
This supplement has been used in connection with the following health conditions:
Apply 5% oil twice per day
A clinical trial compared the topical use of 5% tea tree oil to 5% benzoyl peroxide for common acne. Although the tea tree oil was slower and less potent in its action, it had far fewer side effects and was thus considered more effective overall.1The effectiveness of tea tree oil was confirmed in a six-week double-blind trial. In that study, participants applied a 5% tea tree oil gel to the affected area twice a day for 20 minutes and then washed it off with tap water.2
Apply a 10% cream twice per day
Tea tree oil has been traditionally used to treat athlete’s foot. One trial reported that application of a 10% tea tree oil cream reduced symptoms of athlete’s foot just as effectively as drugs and better than placebo, although it did not eliminate the fungus.4
Swish 15 ml of a 5% or less solution in mouth for 30 to 60 seconds four times per day, then spit out
A small, preliminary trial found that a mouthwash with diluted tea tree oil was effective in decreasing the growth of Candida albicans and in improving symptoms in AIDS patients with oral Candida infections (thrush) that had not responded to drug therapy.5 People in the study took 15 ml of the oral solution (dilution of tea tree oil was not given) four times per day and were instructed to swish it in their mouth for 30 to 60 seconds and then spit it out. For use of tea tree oil as a mouthwash, one should not exceed a 5% dilution and should be extremely careful not to swallow the solution.
Refer to label instructions
The potent effects of some commercial mouthwashes may be due to the inclusion of thymol (from thyme) and eukalyptol (from eucalyptus)—volatile oils that have proven activity against bacteria. One report showed bacterial counts plummet in as little as 30 seconds following a mouthrinse with the commercial mouthwash Listerine™, which contains thymol and eukalyptol.6 Thymol alone has been shown in research to inhibit the growth of bacteria found in the mouth.7, 8 Because of their antibacterial properties, other volatile oils made from tea tree,9 clove, caraway, peppermint, and sage,10 as well as the herbs myrrh11 and bloodroot,12 might be considered in a mouthwash or toothpaste. Due to potential allergic reactions and potential side effects if some of these oils are swallowed, it is best to consult with a qualified healthcare professional before pursuing self-treatment with volatile oils that are not in approved over-the-counter products for halitosis.
Apply shampoo to hair and leave on for one hour before washing out
[1 star] Learn More
An herbal shampoo (Paw Paw Lice Remover Shampoo) containing a standardized extract of paw paw (Asimina triloba), thyme oil, and tee tree oil was found to be toxic to head lice in test tube studies, after which uncontrolled trials were carried out in 13 families.13 The shampoo was applied to the dry hair and left on for one hour before washing out and combing with a fine-toothed comb; this was repeated eight and sixteen days later, after which 100% of the 37 participants were free of lice.
HIV and AIDS Support
Refer to label instructions
A 5% solution of tea tree oil has been shown to eliminate oral thrush in people with AIDS, according to one preliminary trial.14 The volunteers in the study swished 15 ml of the solution in their mouths four times per day and then spit it out. This may cause mild burning for a short period of time after use.
Topically applied tea tree oil has been studied and used successfully as a topical treatment for Trichomonas,Candida albicans, and other vaginal infections.15 Tea tree oil must be diluted when used as a vaginal douche, and should only be used for this purpose under the supervision of a healthcare practitioner. Some physicians suggest using tea tree oil by mixing the full-strength oil with vitamin E oil in the proportion of 1/3 tea tree oil to 2/3 vitamin E oil. A tampon is saturated with this mixture or the mixture is put in a capsule to be inserted in the vagina each day for a maximum of six weeks.
Refer to label instructions
Australian Aboriginals used the leaves of tea tree to treat cuts and skin infections, crushing and applying them to the affected area. Modern herbalists recommend tea tree oil (at a strength of 70–100%) applied moderately in small areas at least twice per day to the affected areas of skin.16 For a variety of reasons, some researchers have suggested that tea tree oil should not be used to treat burns.17
Traditional Use (May Not Be Supported by Scientific Studies)
Australian Aborigines used the leaves to treat cuts and skin infections. They would crush the leaves and apply them to the affected area. Captain James Cook and his crew named the tree “tea tree,” using its leaves as a substitute for tea as well as to flavor beer. Australian soldiers participating in World War I were given tea tree oil as a disinfectant, leading to a high demand for its production.
How It Works
How It Works
The oil contains numerous chemicals known as terpenoids. Australian standards were established for the amount of one particular compound, terpinen-4-ol, which must make up at least 30% and preferably 40–50% of the oil for it to be medically useful. Another compound, cineole, should make up less than 15% and preferably 2.5% of the oil. The oil kills fungus and bacteria, including those resistant to some antibiotics.18, 19 For common acne, a double-blind trial compared the topical use of 5% tea tree oil to 5% benzoyl peroxide.20 Although the tea tree oil was slower and less potent in its action, it had far fewer side effects and was thus considered more effective overall.
A double-blind trial found that a 10% tea tree oil cream was as effective as anti-fungal medicine at improving symptoms associated with athlete’s foot, though it was not more effective than a placebo for eliminating the fungal infection.21 A double-blind trial found 100% tea tree oil applied topically was as effective as the anti-fungal medicine clotrimazole (Lotrimin®, Mycelex®) for people with fungus affecting the toe nails, a condition known as onychomycosis.22 In another double-blind trial with toenail fungus sufferers, a combination of 5% tea tree oil and 2% butenafine (Mentax®), a synthetic anti-fungal drug, in a cream proved more effective than an unspecified concentration of tea tree oil in cream alone.23 The results are not entirely surprising, as the tea tree product alone was probably not at a sufficiently high enough concentration to be effective.
A preliminary trial found that rinsing the mouth with 1 tablespoon (15 ml) tea tree oil solution four times daily effectively treated thrush (oral yeast infections) in AIDS patients.24 Solutions containing no more than 5% should be used orally and should never be swallowed.
A concern for hospital staff and patients is the spread of the bacteria Staphylococcus aureus—sometimes referred to as a “staph infection.” One small clinical trial found that use of a 4% tea tree oil nasal ointment as well as a 5% tea tree oil body wash was slightly more effective than standard drugs used to prevent the spread of the bacteria.25
How to Use It
Oil at a strength of 70–100% should be applied moderately at least twice per day to the affected areas of skin or nail.26 For topical treatment of acne, the oil is used at a dilution of 5–15%. Concentrations as strong as 40% may be used—with extreme caution and qualified advice—as vaginal douches. For thrush in immune-compromised adults, tea tree oil diluted to 5% or less is used in the amount of 1 tablespoon (15 ml) four times daily (as a mouth rinse). Tea tree oil should never be swallowed.
Interactions with Supplements, Foods, & Other Compounds
At the time of writing, there were no well-known supplement or food interactions with this supplement.
Interactions with Medicines
As of the last update, we found no reported interactions between this supplement and medicines. It is possible that unknown interactions exist. If you take medication, always discuss the potential risks and benefits of adding a new supplement with your doctor or pharmacist.
The Drug-Nutrient Interactions table may not include every possible interaction. Taking medicines with meals, on an empty stomach, or with alcohol may influence their effects. For details, refer to the manufacturers’ package information as these are not covered in this table. If you take medications, always discuss the potential risks and benefits of adding a supplement with your doctor or pharmacist.
While tea tree oil can be applied to minor cuts and scrapes, use caution for more extensive areas of broken skin or areas affected by rashes not due to fungus. The oil may burn if it gets into the eyes, nose, mouth, or other tender areas. Some people have allergic reactions, including rashes and itching, when applying tea tree oil.27 For this reason, only a small amount should be applied when first using it.
In case reports, three young boys developed breast enlargement (gynecomastia) after repeated topical application of products that contained lavender oil and tea tree oil. The problem resolved after they stopped using the oils. While a cause–effect relationship was not conclusively proven, it was suggested by the fact that these oils have been found to have estrogen-like effects in test tube studies.28 Tea tree oil should never be swallowed, as it may cause nerve damage and other problems.
1. Bassett IB, Pannowitz DL, Barnetson RS. A comparative study of tea-tree oil versus benzoyl peroxide in the treatment of acne. Med J Austral 1990;53:455–8.
2. Enshaieh S, Jooya A, Siadat AH, Iraji F. The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: a randomized, double-blind placebo-controlled study. Indian J Dermatol Venereol Leprol 2007;73:22–5.
3. Buck DS, Nidorf DM, Addino JG. Comparison of two topical preparations for the treatment of onychomycosis: Melaleuca alternifolia (tea tree) oil and clotrimazole. J Fam Pract 1994;38:601–5.
4. Tong MM, Altman PM, Barnetson RS. Tea tree oil in the treatment of tinea pedis. Aust J Dermatol 1992;33:145–9.
5. Jandourek A, Vaishampayan JK, Vazquez JA. Efficacy of melaleuca oral solution for the treatment of fluconazole refractory oral candidiasis in AIDS patients. AIDS 1998;12:1033–7.
6. Kato T, Iijima H, Ishihara K, et al. Antibacterial effects of Listerine on oral bacteria. Bull Tokyo Dent Coll 1990;31:301–7.
7. Cosentino S, Tuberoso CI, Pisano B, et al. In-vitro antimicrobial activity and chemical composition of Sardinian Thymus essential oils. Lett Appl Microbiol 1999;29:130–5.
8. Petersson LG, Edwardsson S, Arends J. Antimicrobial effect of a dental varnish, in vitro. Swed Dent J 1992;16:183–9.
9. Cox SD, Mann CM, Markham JL, et al. The mode of antimicrobial action of the essential oil of Melaleuca alternifolia (tea tree oil). J Appl Microbiol 2000;88:170–5.
10. Serfaty R, Itic J. Comparative trial with natural herbal mouthwash versus chlorhexidine in gingivitis. J Clin Dent 1988;1:A34–7.
11. Dolara P, Corte B, Ghelardini C, et al. Local anaesthetic, antibacterial and antifungal properties of sesquiterpenes from myrrh. Planta Med 2000;66:356–8.
12. Hannah JJ, Johnson JD, Kuftinec MM. Long-term clinical evaluation of toothpaste and oral rinse containing sanguinaria extract in controlling plaque, gingival inflammation, and sulcular bleeding during orthodontic treatment. Am J Orthod Dentofacial Orthop 1989;96:199–207.
13. McCage CM, Ward SM, Paling CA, et al. Development of a paw paw herbal shampoo for the removal of head lice. Phytomedicine 2002;9:743-8.
14. Jandourek A, Vaishampayan JK, Vazquez JA. Efficacy of melaleuca oral solution for the treatment of fluconazole refractory oral candidiasis in AIDS patients. AIDS 1998;12:1033–7.
15. Pena E. Melaleuca alternifolia oil: Its use for trichomonal vaginitis and other vaginal infections. Obstet Gynecol 1962;19:793–5.
16. Carson CF, Riley TV. Antimicrobial activity of the essential oil of Melaleuca alternifolia: A review. Lett Appl Microbiol 1993;16:49–55.
17. Faoagali J, George N, Leditschke JF. Does tea tree oil have a place in the topical treatment of burns? Burns 1997;23:349–51.
18. Carson CF, Riley TV. Antimicrobial activity of the essential oil of Melaleuca alternifolia—A review. Lett Appl Microbiol 1993;16:49–55.
19. Carson CF, Cookson BD, Farrelly HD, Riley T. Susceptibility of methicillin-resistant Staphylococcus aureus to the essential oil of Melaleuca alternifolia. J Antimicrobial Chemother 1995;35:421–4.
20. Bassett IB, Pannowitz DL, Barnetson RS. A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne. Med J Austral 1990;153:455–8.
21. Tong MM, Altman PM, Barnetson RS. Tea tree oil in the treatment of tinea pedis. Austral J Dermatol 1992;33:145–9.
22. Buck DS, Nidorf DM, Addino JG. Comparison of two topical preparations for the treatment of onychomycosis: Melaleuca alternifolia (tea tree) oil and clotrimazole. J Garm Pract 1994;38:601–5.
23. Syed TA, Qureshi ZA, Ali SM, et al. Treatment of toenail onychomycosis with 2% butenafine and 5% Melaleuca alternifolia (tea tree) oil in cream. Trop Med Intl Health 1999;4:284–7.
24. Jandourek A, Vaishampayan JK, Vazquez JA. Efficacy of melaleuca oral solution for the treatment of fluconazole refractory oral candidiasis in AIDS patients. AIDS 1998;12:1033–7.
25. Caelli M, Porteous J, Carson CF, et al. Tea tree oil as an alternative topical decolonization agent for methicillin-resistant Staphylococcus aureus. J Hospital Infect 2000;46:236–7.
26. Brown DJ. Phytotherapeutic approaches to common dermatological conditions. Quart Rev Natural Med 1998;Summer:161–73.
27. Knight TE, Hansen BM. Melaleuca oil (tea tree oil) dermatitis. Med J Australia 1994;30:423–7.
28. Henley DV, Lipson N, Korach KS, Bloch CA. Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med 2007;356:479–85.
The information presented in Aisle7 is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires June 2014.
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