Australian tea tree oil, Bogaskin® (veterinary formulation), breathaway, Burnaid®, cymene, malaleuca, Malaleuca alternifolia, Melaleuca alternifolia Cheel, Melaleuca Alternifolia Hydrogel® (burn dressing), melaleuca oil, melaleucae, oil of mela-leuca, oleum, Oleum melaleucae, T36-C7, tea tree oil, Tebodont®, teebaum, terpinen, terpinen-4-ol, terpinenol-4, ti tree, TTO.
Note: Should not be confused with cajeput oil, niauouli oil, kanuka oil, or manuka oil obtained from other Melaleuca species.
Tea tree oil is obtained by steam distillation of the leaves of Melaleuca alternifolia. Tea tree oil is purported to have antiseptic properties and has been used traditionally to prevent and treat infections. While numerous laboratory studies have demonstrated antimicrobial properties of tea tree oil (likely due to the compound terpinen-4-ol), only a small number of high-quality trials have been published. Human studies have focused on the use of topical tea tree oil for fungal infections (including fungal infections of the nails and athlete's foot), acne, and vaginal infections. However, there is a lack of definitive available evidence for the use of tea tree oil in any of these conditions, and further study is warranted.
Tea tree oil should not be used orally; there are reports of toxicity after consuming tea tree oil by mouth. When applied to the skin, tea tree oil is reported to be mildly irritating and has been associated with the development of allergic contact dermatitis, which may limit its potential as a topical agent for some patients.
Although available in many products, little information is available from human studies to evaluate the benefit of tea tree oil used on the skin for the treatment of acne. Tea tree oil may reduce the number of inflamed and non-inflamed lesions.
Allergic skin reactions:
Early small studies show that tea tree oil applied to this skin may reduce histamine-induced inflammation. Further research is needed to confirm these results.
Athlete's foot (tinea pedis):
Early studies report that tea tree oil may have activity against several fungal species. However, at this time there is not enough information to make recommendations for or against the use of tea tree oil on the skin for this condition.
Tea tree oil is used in mouthwash for dental and oral health. However, there is currently insufficient evidence in humans to recommend for or against this use of tea tree. Tea tree oil can be toxic when taken by mouth and therefore should not be swallowed.
Early research reports that the use of 5% tea tree oil shampoo on mild-to-moderate dandruff may be effective and well tolerated. Further research is needed to confirm these results.
Study results on the effects of tea tree oil mouthwash on gum inflammation and plaque are mixed. Further research is needed before a strong conclusion can be drawn.
Eye infections (ocular parasitic mites):
Early studies found that tea tree oil helped rid the eye area of the mite infection caused by ocular parasitic mites. Large, well-designed clinical trials are needed before a strong recommendation can be made.
Fungal nail infection (onychomycosis):
Although tea tree oil is thought to have activity against several fungus species, there is not enough information to make recommendations for or against the use of tea tree oil on the skin for this condition.
Laboratory studies show that tea tree oil has activity against some viruses, and it has been suggested that a tea tree gel may be useful as a treatment on the skin for genital herpes. However, there is currently not enough information to make a recommendation for or against this use of tea tree oil.
Early studies have found that tea tree alone or in combination with other agents may be effective against lice. However, large, well-designed trials are still needed before a strong recommendation can be made.
Methicillin-resistant Staphylococcus aureus (MRSA) chronic infection (colonization):
Laboratory studies report that tea tree oil has activity against methicillin-resistant Staphylococcus aureus (MRSA). It has been proposed that using tea tree oil ointment in the nose and a tea tree wash on the body may treat colonization by these bacteria. However, there is currently not enough information from human studies to make recommendations for or against this use of tea tree oil.
Thrush (Candida albicans of the mouth):
In laboratory studies, tea tree oil has been shown to kill fungus and yeast such as Candida albicans. However, at this time, there is not enough information available from human studies to make recommendations for or against this use of tea tree oil. Tea tree oil can be toxic when taken by mouth and therefore should not be swallowed.
Vaginal infections (yeast and bacteria):
In laboratory studies, tea tree oil has been shown to kill yeast and certain bacteria. However, at this time there is not enough information available from human studies to make recommendations for or against this use of tea tree oil for vaginal infections. Although tea tree oil may reduce itching caused by yeast or bacteria, it may cause itching from dry skin or allergy.
Although there is no proven effective dose, a common dose studied in trials is 5-10% tea tree oil in gel or shampoo form applied on the skin daily for up to four weeks. While 100% tea tree oil is sometimes used for certain conditions, such as fungal nail infections, it is often diluted with inactive ingredients. Due to reports of severe side effects after tea tree oil ingestion, it is strongly recommended that tea tree oil not be taken by mouth. Although tea tree oil solution has been used as a mouthwash, it should not be swallowed.
There is insufficient research to recommend the safe use of tea tree oil in children.
There are many reports of allergy to tea tree oil when taken by mouth or used on the skin. Skin reactions range from mild contact dermatitis to severe blistering rashes. People with a history of allergy to tea tree oil (Melaleuca alternifolia), to any of its components, or to plants that are members of the myrtle (Myrtaceae) family, balsam of Peru, or benzoin, should not use tea tree oil. Use cautiously if allergic to eucalyptol as many tea tree preparations contain eucalyptol.
Tea tree oil taken by mouth has been associated with potentially severe reactions, even when used in small quantities. Several reports describe people using tea tree oil by mouth who developed severe rash, reduced immune system function, abdominal pain, diarrhea, lethargy, drowsiness, inflammation of the corners of the mouth, slow or uneven walking, confusion, or coma. There have also been reports of nausea, unpleasant taste, burning sensation, and bad breath associated with tea tree oil use. Many tea tree preparations contain large volumes of alcohol.
When used on the skin, tea tree oil may cause allergic rash, redness, blistering, and itching. This may be particularly severe in people with pre-existing skin conditions such as eczema. Use of tea tree oil inside of the mouth or eyes can cause irritation. Animal research suggests that tea tree oil used on the skin in large quantities can cause serious reactions such as difficulty walking, weakness, muscle tremor, slowing of brain function, and poor coordination. When applied in the ears of animals, 100% tea tree oil has caused reduced hearing, although a 2% solution has not led to lasting changes in hearing. The effect of tea tree oil on hearing when used in the ears of humans is not known.
Not enough scientific information is available to recommend tea tree oil during pregnancy or breastfeeding. Animal studies suggest caution in the use of tea tree oil during childbirth because tea tree oil has been reported to decrease the force of spontaneous contractions, which theoretically could put the baby and mother at risk. Women who are breastfeeding should not apply tea tree oil to the breast or nipple since it may be absorbed by the infant.