Tea Tree Oil

• How It Works

  Topical tea tree oil may be effective in treating certain skin conditions, but research is limited.

  Tea tree oil is the essential oil distilled from Melaleuca alternifolia, a plant native to Australia. It has been used in traditional medicine for its antiseptic and anti-inflammatory properties to treat various skin conditions and infections. It is also a popular ingredient in skin and hair products. In lab studies, tea tree oil killed several bacteria and fungi most commonly found in skin infections and acne.

  Studies on the use of tea tree oil in humans are limited. In healthy volunteers, a topical tea tree oil extract reduced inflammation caused by histamine exposure. It has also shown some benefit in individuals with athlete’s foot, acne, cold sores, and warts, but more studies are needed.

• Purported Uses
  • To treat skin conditions
    In a small older study, tea tree oil was as effective as benzoyl peroxide for acne, but additional study is needed.
  • To treat infections
    Studies on whether tea tree oil is effective in treating fungal infections are mixed. A small study suggests it may be helpful for cold sores, but further study is necessary.
  • To reduce inflammation
    Small studies suggest tea tree oil may reduce inflammation related to histamine exposure, or from insect bites or stings.
  • To treat mucositis (painful mouth sores, swelling)
    There are no clinical data to prove this claim. Intake of tea tree oil by mouth can cause severe toxicity.
• Patient Warnings
  • Tea tree oil should not be taken orally, as severe side effects have occurred.
• Do Not Take If
  • You have sensitive skin: There have been a number of case reports of skin rash and other reactions with the use of tea tree oil.
• Side Effects

  Case reports

  • Topical: Local skin irritation, itching, redness, and swelling; breast tissue enlargement in boys with application of lavender and tea tree oils.
  • Oral: Disorientation, systemic body rash, abnormal white blood cell counts, and coma.
• Scientific Name

  Melaleuca alternifolia

• Clinical Summary

  Tea tree oil is an essential oil distilled from the leaves of Melaleuca alternifolia, a plant native to Australia. It has been used in traditional medicine for its antiseptic and anti-inflammatory properties to treat various skin conditions and infections. It has also been incorporated into many topical formulations to treat cutaneous infections, speed wound healing, and as an ingredient in skin and hair products.

  In vitro studies suggest wide-spectrum antimicrobial ^(2) (12), antiviral ⁽²⁰⁾, antiprotozoal ⁽²¹⁾, anti-inflammatory ⁽²²⁾ and antiproliferative ^(14) (15) properties. Animal studies also suggest cytotoxic effects  ⁽²³⁾.

  Preliminary studies in humans suggest various topical tea tree oil formulations may help treat acne ⁽⁵⁾, athlete’s foot ^(6) (9), fungal nail infections ⁽⁷⁾, histamine-induced skin inflammation ⁽⁸⁾, warts ⁽¹⁶⁾, cold sores ⁽¹¹⁾, chalazia ⁽²⁶⁾, and dermatitis ⁽¹⁸⁾. However, additional studies are needed to confirm under what conditions topical applications may be effective.

• Purported Uses
  • Infections
  • Skin conditions
  • Inflammation
  • Mucositis
• Mechanism of Action

  Terpinen-4-ol, a major constituent of tea tree oil, exhibited antimicrobial activity against Candida albicans, Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. Terpin-4-ol, alpha-terpineol, and alpha-pinene also had antimicrobial effects against Staphylococcus epidermidis and Propionibacterium acnes ⁽²⁾. Terpinen-4-ol suppressed inflammatory mediator production by activating human monocytes ⁽⁸⁾.

  A tea tree oil concentrate prevented influenza virus from entering the host cells by disturbing the normal viral membrane fusion procedure ⁽²⁵⁾. Other in vitro studies indicate that tea tree oil has weak estrogenic and antiandrogenic properties that may alter the estrogen and androgen signaling pathways ⁽¹³⁾. At the same time, the notion that tea tree oil has hormone-modulating properties has been challenged, and further confirmatory research is needed ⁽²⁷⁾.

  Skin irritation following use of tea tree oil is due to its auto-oxidation and formation of epoxide intermediates via arene-epoxidation reactions catalyzed by human cytochrome P450 enzymes ⁽¹⁷⁾.

• Warnings
  • Tea tree oil should not be taken orally, as severe side effects have occurred.
• Contraindications
  • Patients with sensitive skin should use caution with topical applications, as skin reactions have been reported.
• Adverse Reactions

  Case Reports
  Topical: Skin irritation and contact dermatitis ^{(3) (10) (19) (24)}; gynecomastia in prepubertal boys with repeated application of lavender and tea tree oils ⁽¹³⁾.
  Oral: Disorientation, systemic contact dermatitis, neutrophil leukocytosis, and coma ⁽⁴⁾.

• References

  1. Carson CF, Hammer KA, Riley TV. Melaleuca alternifolia (Tea Tree) oil: a review of antimicrobial and other medicinal properties. Clin Microbiol Rev. 2006 Jan; 19(1):50-62.

  2. May J, et al. Time-kill studies of tea tree oils on clinical isolates. J Antimicrob Chemother 2000;45:639-43.

  3. Rubel DM, Freeman S, Southwell IA. Tea tree oil allergy: what is the offending agent? Report of three cases of tea tree oil allergy and review of the literature. Australia J Dermatol 1998;39:244-7.

  4. Carson C, Riley TV, Cookson BD. Efficacy and safety of tea tree oil as a topical antimicrobial agent. J Hosp Infect 1998;40:175-8.

  5. Bassett IB, Pannowitz DL, Barnetson RS. A comparative study of tea tree oil versus benzol peroxide in the treatment of acne. Med J Aust 1990;153:455-8.

  6. Tong MM, Altman PM, Barnetson RS. Tea tree oil in the treatment of tinea pedis. Australia J Dermatol 1992;33:145-9.

  7. 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.

  8. Koh KJ, et al. Tea tree oil reduces histamine-induced skin inflammation. Br J Dermatol 2002;147:1212-7.

  9. Satchell AC, et al. Treatment of interdigital tinea pedis with 25% and 50% tea tree oil solution: A randomized, placebo-controlled, blinded study. Australas J Dermatol 2002; 43: 175-8.

  10. Storan ER, Nolan U, Kirby B. Allergic contact dermatitis caused by the tea tree oil-containing hydrogel Burnshield(R). Contact Dermatitis. May 2016;74(5):309-310.

  11. Carson CF, et al. Melaleuca alternifolia (tea tree) oil gel (6%) for the treatment of recurrent herpes labialis. J Antimicrob Chemother 2001; 48: 450-1.

  12. Bagg J, et al. Susceptibility to Melaleuca alternifolia (tea tree) oil of yeasts isolated from the mouths of patients with advanced cancer. Oral Oncol 2006; 42(5): 487-92.

  13. Henley DV, Lipson N, Korach KS, et al. Prepubertal gynecomastia linked to lavender and tea tree oils. N Engl J Med 2007;356(5):479-85.

  14. Calcabrini A, Stringaro A, Toccacieli L, et al. Terpinen-4-ol, the main component of Melaleuca alternifolia (tea tree) oil inhibits the in vitro growth of human melanoma cells. J Invest Dermatol. 2004 Feb;122(2):349-60.

  15. Greay SJ, Ireland DJ, Kissick HT, et al. Induction of necrosis and cell cycle arrest in murine cancer cell lines by Melaleuca alternifolia (tea tree) oil and terpinen-4-ol. Cancer Chemother Pharmacol. 2010 Apr;65(5):877-88.

  16. Millar BC, Moore JE. Successful topical treatment of hand warts in a paediatric patient with tea tree oil (Melaleuca alternifolia). Complement Ther Clin Pract. 2008 Nov;14(4):225-7.

  17. Meesters RJ, Duisken M, Hollender J. Cytochrome P450-catalysed arene-epoxidation of the bioactive tea tree oil ingredient p-cymene: indication for the formation of a reactive allergenic intermediate? Xenobiotica. 2009 Sep;39(9):663-71.

  18. Wallengren J. Tea tree oil attenuates experimental contact dermatitis. Arch Dermatol Res. 2011 Jul;303(5):333-8.

  19. Posadzki P, Alotaibi A, Ernst E. Adverse effects of aromatherapy: a systematic review of case reports and case series. Int J Risk Saf Med. 2012 Jan 1;24(3):147-61.

  20. Li X, Duan S, Chu C, et al. Melaleuca alternifolia concentrate inhibits in vitro entry of influenza virus into host cells. Molecules. 2013 Aug 9;18(8):9550-66.

  21. Mikus J, Harkenthal M, Steverding D, Reichling J. In vitro effect of essential oils and isolated mono- and sesquiterpenes on Leishmania major and Trypanosoma brucei. Planta Med. 2000 May; 66(4):366-8.

  22. Ninomiya K, Hayama K, Ishijima SA, et al. Suppression of inflammatory reactions by terpinen-4-ol, a main constituent of tea tree oil, in a murine model of oral candidiasis and its suppressive activity to cytokine production of macrophages in vitro. Biol Pharm Bull. 2013;36(5):838-44.

  23. Ireland DJ, Greay SJ, Hooper CM, et al. Topically applied Melaleuca alternifolia (tea tree) oil causes direct anti-cancer cytotoxicity in subcutaneous tumour bearing mice. J Dermatol Sci. 2012 Aug;67(2):120-9.

  24. de Groot AC, Schmidt E. Tea tree oil: contact allergy and chemical composition. Contact Dermatitis. Sep 2016;75(3):129-143.

  25. Li X, Duan S, Chu C, et al. Melaleuca alternifolia concentrate inhibits in vitro entry of influenza virus into host cells. Molecules. 2013 Aug 9;18(8):9550-66.

  26. Yam JC, Tang BS, Chan TM, et al. Ocular demodicidosis as a risk factor of adult recurrent chalazion. Eur J Ophthalmol. Mar-Apr 2014;24(2):159-163.

  27. Carson CF, Tisserand R, Larkman T. Lack of evidence that essential oils affect puberty. Reprod Toxicol. Apr 2014;44:50-51.