What is Tea Tree Oil?

Latin Name: Melaleuca alternifolia
Other Names: Melaleuca oil, Australian tea tree oil

Tea tree oil is an essential oil obtained by steam distillation of the leaves of Melaleuca alternifolia, a plant native to Australia.

Historically, the leaves were used as a substitute for tea, which is how tea tree oil got its name. The part used medicinally is the oil from the leaves.

Why Do People Use Tea Tree Oil?

Tea tree has a long history of traditional use. Australian aboriginals used tea tree leaves for healing skin cuts, burns, and infections by crushing the leaves and applying them to the affected area. Tea tree oil contains consituents called terpenoids, which have been found to have antiseptic and antifungal activity. The compound terpinen-4-ol is the most abundant and is thought to be responsible for most of tea tree oil's antimicrobial activity. 

People use tea tree oil for the following conditions:

• Acne
• Athlete's foot
• Dandruff
• Vaginitis
• Thrush
• Periodontal disease
• As an antiseptic
• Boils
• Lice
• Eczema
• Psoriasis
• Yeast infection

Sources of Tea Tree Oil

Tea tree oil is most commonly found as a pure essential oil. It is also an ingredient in creams, ointments, lotions, soaps, and shampoos.

Tea tree oil should not be confused with Chinese tea oil, cajeput oil, kanuka oil, manuka oil, ti tree oil, and niauouli oil.

What is the Evidence for Tea Tree Oil?

There have only been a few, older clinical trials looking at the effectiveness of tea tree oil in humans.

• Athlete's Foot

A randomized controlled trial examined the use of 25% tea tree oil solution, 50% tea tree oil solution, or placebo in 158 people with athlete's foot. After twice daily applications for 4 weeks, the two tea tree oil solutions were found to be significantly more effective than placebo.

In the 50% tea tree oil group, 64% were cured, compared to 31% in the placebo group. Four people using the tea tree oil withdrew from the study because they developed dermatitis (which improved after discontinuing tea tree oil use). Otherwise, there were no significant side effects.

• Fungal Infection of the Toenails

A randomized, controlled trial published in the Journal of Family Practice looked at the twice-daily application of 100% tea tree oil or 1% clotrimazole solution (a topical antifungal medication) in 177 people with toenail fungal infection. After 6 months, the tea tree oil was found to be as effective as the topical antifungal, based on clinical assessment and toenail cultures.

Another randomized, controlled trial examined the effectiveness and safety of a cream containing 5% tea tree oil and 2% butenafine hydrochloride in 60 people with toenail fungal infection. After 16 weeks, 80% of people using the cream had significant improvement compared to none in the placebo group. Side effects included mild inflammation.

A third double-blind study looked at 100% tea tree oil compared with a topical antifungal, clotrimazole, in 112 people with fungal infections of the toenails. The tea tree oil was as effective as the antifungal.

• Acne

A single-blind randomized trial by the Department of Dermatology at the Royal Prince Alfred Hospital in Australia compared the effectiveness and tolerance of 5% tea tree oil gel with 5% benzoyl peroxide lotion in 124 people with mild to moderate acne. People in both groups had a significant reduction in inflamed and non-inflammed acne lesions (open and closed comedones) over the three month period, although tea tree oil was less effective than benzoyl peroxide.

Although the tea tree oil took longer to work initially, there were fewer side effects with tea tree oil. In the benzoyl peroxide group, 79 percent of people had side effects including itching, stinging, burning, and dryness. Researchers noted that there were far less side effects in the tea tree oil group.

• Dandruff

A single-blind study examined the use of 5% tea tree oil shampoo or placebo in 126 people with mild to moderate dandruff. After 4 weeks, the tea tree oil shampoo significantly reduced symptoms of dandruff.

Safety Concerns

One study shows that tea tree oil may alter hormone levels. There have been three case reports of topical tea tree oil products causing unexplained breast enlargement in boys. People with hormone-sensitive cancers or pregnant or nursing women should avoid tea tree oil. 

For more information, read Lavender and Tea Tree Oils Linked to Breast Enlargement in Boys.

Occasionally, people may have allergic reactions to tea tree oil, ranging from mild contact dermatitis to severe blisters and rashes. Undiluted tea tree oil may cause skin irritation, redness, blistering, and itching. Tea tree oil should not be taken internally, even in small quantities. It can cause impaired immune function, diarrhea, and potentially fatal central nervous system depression (excessive drowsiness, sleepiness, confusion, coma).

The tea tree oil in commercial toothpastes and mouthwashes is generally considered to be acceptable because it is not swallowed. Avoid homemade tea tree oil mouthwashes. Seek medical attention if you experience symptoms of overdose: excessive drowsiness, sleepiness, poor coordination, diarrhea, vomiting.

Don't use tea tree oil if you are pregnant or breastfeeding.

Keep tea tree oil out of the reach of children and pets.