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.
NB! The below doses are based on scientific research, publications, traditional use, or expert opinion. Many herbs and supplements have not been thoroughly tested, and safety and effectiveness may not be proven. Brands may be made differently, with variable ingredients, even within the same brand. The below doses may not apply to all products. You should read product labels, and discuss doses with a qualified healthcare provider before starting therapy.
Adults (18 years and older)
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.
Children (younger than 18 years)
There is insufficient research to recommend the safe use of tea tree oil in children.
NB! There is no guarantee of strength, purity or safety of products, and effects may vary. You should always read product labels. If you have a medical condition, or are taking other drugs, herbs, or supplements, you should speak with a qualified healthcare provider before starting a new therapy. Consult a healthcare provider immediately if you experience side effects.
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.
Side Effects and Warnings
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.
Pregnancy and Breastfeeding
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.