Tea tree oil is an essential oil regarded for its antimicrobial activity. It is applied topically primarily for the treatment of acne, athlete’s foot, lice, nail fungus and dandruff (1).
Tea tree oil is commonly available as an essential oil and as an active ingredient in over-the-counter products such as lotions and shampoos.
Tea tree oil is distilled from the leaves of the Melaleuca alternifolia plant — native to Australia — and has been used as a traditional medicine in Aboriginal communities for centuries. It contains a number of compounds, including terpinen-4-ol, which have been shown to kill certain bacteria, viruses and fungi.
These properties make tea tree oil a valued natural remedy for treating bacterial and fungal skin conditions, preventing infection and promoting healing. In vitro data also demonstrates its anti-inflammatory properties.
Although early data supports the long-held belief of tea tree oil’s medicinal value, researchers stress the need for large randomized clinical trials to determine its exact role as a topical medicinal agent (2).
1 Tea tree oil has wide-spectrum antibacterial activity. Tea tree oil has emerged as an effective topical antimicrobial agent against certain antibiotic-resistant infections. This news comes at an important time, as the emergence of resistant microorganisms found in hospitals and in the community is of great concern.
Studies find that incorporating tea tree oil with proper handwashing techniques may reduce the transmission of many antibiotic-resistant infections, including methicillin-resistant Staphylococcus aureus (MRSA) 3.
A study testing several types of hand washes showed that adding tea tree oil to the cleansers boosted their effectiveness against Escherichia coli (E. coli) — bacteria that can cause severe abdominal cramps, bloody diarrhea and vomiting.
The active compound, terpinen-4-ol, has also shown antimicrobial activity against several respiratory tract pathogens, including Streptococcus pneumoniae (the bacteria that causes pneumonia, sinus infections, ear infections and meningitis (4,5).
2 Tea tree oil has antiviral activity. In a recent study, tea tree oil showed 100 percent inhibition of influenza type A (H1N1) virus at 0.01 percent concentration. In addition, 30 minute exposure of type A virus to tea tree oil vapor caused 100 percent inhibition (6).
Another study found tea tree oil in aerosol form to be have strong antiviral action (7).
A 2001 in vitro study revealed that a combination of tea tree oil and eucalyptus oil worked effectively against the herpes simplex virus (HSV); There are two types of HSV: HSV type 1 (most commonly causes cold sores) and HSV type 2 (causes genital herpes, but can also infect the mouth) (8, 9).
The results have been mixed, however, with some studies showing inhibited HSV replication and others showing little to no effect. Further studies are needed.
3 Tea tree oil can effectively treat cold sores. These fluid-filled blisters (caused by HSV-1) appear on and around the lips and affect 20 to 40 percent of the population, some of whom develop frequent attacks. According to the Journal of Antimicrobial Chemotherapy, the topical application of 6 percent tea tree oil is as effective as medicated topical therapies in helping promote healing (10). This treatment can be an option for those seeking a natural alternative to combat their recurrent cold sores.
4 Tea tree oil can treat warts. Warts are skin growths that are caused by an infection with the human papillomavirus (HPV). While these growths are not dangerous, they are contagious, unsightly and can be painful. According to one report published in Complementary Therapies in Clinical Practice, the daily application of tea tree oil to the fingers of pediatric patients, successfully removed the warts. Treatment lasted 12 days (11).
5 Tea tree oil helps treat acne. This essential oil’s antimicrobial and anti-inflammatory properties pack a one-two punch against acne. This can help prevent acne lesions, while also reducing swelling associated with inflammatory acne. The results of a study, published in a 2017 issue of the Australasian Journal of Dermatology, concluded that the use of the tea tree oil products significantly improved mild to moderate acne — mean total lesion counts went from 23 at baseline to 10 at 12 weeks. The products were also well tolerated, with minor peeling and dryness as reported side effects (12).
A review of seven studies, including three double-blind trials, published in the International Journal of Antimicrobial Agents in 2015, concluded that products containing at least 5 percent tea tree oil, applied twice daily for multiple weeks, are likely to reduce acne (13).
6 Tea tree oil helps treat athlete’s foot. Athlete’s foot is a common fungal infection that usually begins between the toes, and causes a scaly rash with symptoms of itching, stinging and burning. In a study of 104 participants, those treated with tea tree oil showed significant improvement in symptoms when compared to the placebo group (14).
Another study carried out to evaluate the efficacy of 25 percent and 50 percent tea tree oil in the treatment of athlete’s foot yielded equally promising results. Researchers noted a marked improvement seen in 68 percent of the 50 percent tea tree oil group and 72 percent of the 25 percent tea tree oil group, compared to 39 percent in the placebo group (15).
7 Tea tree oil helps treat nail fungus. A study evaluating the effectiveness of 100 percent tea tree oil and 1 percent clotrimazole solution (a common antifungal medication) for the treatment of toenail fungus, found both treatments provided improvement in nail appearance and symptoms.
After six months of treatment, about 60 percent of people in each group experienced partial or full resolution of the fungus.
Tea tree oil, however, is unlikely to fully cure a well-established toenail fungus infection, since the infection tends to be based in the nail matrix, or “root.”
8 Tea tree oil helps treat head lice. While topical insecticides have long been the go-to treatment for head lice, public concern over their safety has led to an increase in alternative treatments. As a result, natural remedies, such as essential oils, have been proposed to treat this parasitic infestation. At the conclusion of a 2012 study, researchers found that treatment with a 1 percent tea tree oil solution was capable of killing 100 percent head lice within 30 minutes (16).
Research also suggests that tea tree oil and lavender work together effectively to tackle infestations.
9 Tea tree oil helps control dandruff. One hundred twenty-six male and female patients were randomly assigned to receive either 5 percent tea tree oil shampoo or placebo. After four weeks of daily use, the 5 percent tea tree oil shampoo group showed a 41 percent improvement compared with 11 percent in the placebo group. Statistically significant improvements were also observed regarding the itchiness and greasiness components of the patients’ self-assessments (17).
10 Tea tree oil helps treat contact dermatitis. Contact dermatitis is a common skin condition characterized by a red, itchy rash caused by direct contact with a substance or an allergic reaction to it. A 2011 study found that treatment with tea tree oil reduced allergic contact dermatitis symptoms by 40 percent in comparison to traditional topical treatments — zinc oxide (17 percent) or clobetason butyrate (23 percent) 18.
A study evaluating the efficacy of tea tree oil in the treatment of nickel-induced contact hypersensitivity in human skin, found that topical application of 100 percent oil significantly reduced the flare area and helped reduce redness (19).
11 Tea tree oil may speed wound healing. The results of a small study (ten participants) evaluating the effect of tea tree oil on wound healing, demonstrated the essential oil’s ability to decrease healing time in all but one of the participants (20).
Some small clinical studies have indicated that the anti-inflammatory, immunomodulatory and antimicrobial activities of this essential oil possibly contribute to its pro-wound healing properties (21).
12 Tea tree oil may treat gingivitis. The anti-inflammatory properties of a mouthwash made from tea tree oil appear to be a valuable non-toxic adjunct in the management of gingivitis (a form of gum disease that occurs when plaque builds up on teeth and causes the inflammation of the surrounding gum tissue).
In a 2017 comparative study, 16 participants with gingivitis used one of four types of mouthwash. Tea tree oil provided a greater improvement in the symptoms of pain, inflammation and bleeding associated with gingivitis compared to chlorhexidine, a common chemical compound used in commercial mouthwashes.
It was not, however, as effective at controlling bacterial plaque as the chlorhexidine rinse (22).
13 Tea tree oil may help treat chronic periodontitis. Periodontitis is a gum infection that damages the soft tissue and destroys the bone that supports teeth. Local application of tea tree oil gel may provide some beneficial effects by augmenting the results of the conventional periodontal therapy.
According to the Journal of Indian Society of Periodontology, tea tree oil also has the potential to reduce inflammation and promote healing of periodontal tissues (23).
14 Tea tree oil may help treat and prevent eye conditions. The results of one study, published in a 2014 issue of the European Journal of Ophthalmology demonstrated the effectiveness of a tea tree oil eyelid scrub as an effective treatment in preventing recurrent chalazions (24). A chalazion is a slowly developing lump that forms due to blockage and swelling of an oil gland in the eyelid.
Tea tree oil also brought relief to 24 patients suffering from itchy eyelids due to a demodex folliculorum mite infestation. D. folliculorum mites live in or around hair follicles, usually the eyelids and eyelashes, and are typically harmless. However, larger numbers of mites can cause skin problems, such as itching.
After 4 weeks of 5 percent tea tree oil treatment, 16 patients were totally free of itching and the remaining 8 patients had different degrees of relief (25).
15 Tea tree oil may help prevent skin cancer. An in vitro study demonstrated the potential anti-tumoral activity of tea tree oil against human melanoma cells. Melanoma is the most serious type of skin cancer. Both the complex oil (tea tree oil) and its main active component terpinen-4-ol were able to induce apoptosis (or cell death) of melanoma cells (26).
A three-year study by the University of Western Australia’s Tea Tree Oil Research Group found solid tumors grown under the skin in mice and treated with a tea tree oil formulation caused inhibition of tumor growth and tumor regression within a day of treatment. Within three days, the tumors could not be detected (27).
While human clinical trials with pre-cancerous lesions are needed, researchers are pleased with these early results.
When used topically, tea tree oil is generally safe. However, several adverse reactions have been reported. Tea tree oil can be irritating to the skin, especially when applied in its undiluted, pure form.
1 Tea treat oil may cause skin irritation. When used topically, local skin irritation and/or an allergic reaction including itching, redness, burning, dryness and swelling have been reported. Individuals who have sensitive skin or related conditions like eczema or rosacea should take caution.
2 Tea tree oil is toxic when swallowed, especially at full strength. Serious side effects can occur, including disorientation, body rash, a lack of muscle control or coordination of voluntary movements (ataxia), decreasing levels of consciousness and coma (28).
3 Repeated application of tea tree oil can cause swelling of the breast tissue (gynecomastia) in prepubescent boys. According to The New England Journal of Medicine, researchers have found a link between the repeated topical application of lavender oil and tea tree oil and gynecomastia in young boys. Gynecomastia resolved in each patient shortly after the use of products containing these oils was discontinued (29).
Tea tree oil is widely available as a 100 percent undiluted or “neat” oil. Diluted forms are also available, ranging from 5 to 50 percent strength.
The recommended tea tree oil dosage and length of treatment depend on several factors, including the condition requiring treatment, its severity and the concentration of the tea tree oil.
The following are general recommendations; the proper dosage should be recommended by a health professional.
Acne: Apply 5 percent gel to acne twice a day for 20 minutes; rinse off with water.
Athletes foot: Apply a light coating of diluted oil (25 to 50 percent) to affected areas three or four times a day; continue use for two weeks after symptoms resolve to make sure that the fungus is eradicated.
Finger and toenail fungal infections: Apply a drop or two of 100 percent tea tree oil to the discolored nail two or three times a day; avoid any skin area to prevent irritation.
Dandruff: Add 5 to 10 drops of tea tree essential oil to your current shampoo bottle and shake well. Massage into your scalp gently and rinse thoroughly. You can also look for a shampoo that includes 5 percent tea tree oil and use it as directed on the label.
Wounds: Mix 1 ½ tablespoons of a 10 percent tea tree oil solution to a cup of warm water and use it to rinse and clean infected wounds.
What is tea tree oil good for? Tea tree oil is believed to offer several benefits to the skin due to its antimicrobial and anti-inflammatory properties. It is often used to treat acne, athlete’s foot, lice, nail fungus and insect bites.
Where does tea tree oil come from? Tea tree oil is an essential oil that is derived from the leaves of Melaleuca alternifolia, a plant native to Australia. The oil is extracted from the leaves by steam distillation.
Does tea tree oil come from the same plant that makes tea? No. Tea tree oil comes from the Melaleuca alternifolia plant, while the leaves used to make black, green and oolong tea come from a specific species of plant known as the camellia sinensis.
What is terpinen-4-ol? It is the most active constituent in tea tree oil and has been shown to have antimicrobial and anti-inflammatory properties.
Where can tea tree oil be bought? Tea tree oil is available at most health food and herb stores. When purchasing 100 percent tea tree oil, look for one that contains least 30 percent terpinen-4-ol — the main beneficial compound known for its antimicrobial properties.
How is tea tree oil applied? Tea tree oil should only be applied topically. Ingesting it is toxic and can cause serious health complications. When applied to the skin, it should be diluted with a carrier oil (such as jojoba, coconut or almond oil) to prevent skin irritation.
If you have sensitive skin or are eczema-prone, test a small area (like the skin on your wrist) before applying it somewhere else like the sensitive skin of your face.
What happens if tea tree oil is not diluted? Tea tree oil might be natural, but that does not mean it will not cause irritation. One hundred percent undiluted or “neat” oil can cause skin irritation and/or an allergic reaction, resulting in itching, redness, burning, dryness and swelling.
How do you dilute tea tree oil? The process of diluting tea tree oil entails mixing several drops with a carrier oil. The carrier oil/tea tree oil ratio depends on what is being treated. For the treatment of acne, mixing two teaspoons of carrier oil with 15 drops of pure tea tree oil (to get a five percent concentration) has been shown to be effective. To be safe, buying tea tree oil that is already diluted is recommended.
Does tea tree oil have a smell? Pure tea tree oil smells like camphor and eucalyptus. It has also been described as having a medicinal and earthy smell. It may take on a different smell when mixed with carrier oils.
How do you use tea tree oil for acne? Based on studies, applying a 5 percent gel to acne twice a day (every day) for 20 minutes then rinsing face with water, has been shown to be effective. For those who do not have sensitive skin, dabbing blemishes with a Q-tip dampened with tea tree oil can be an effective spot treatment. Discontinue use, however, if irritation occurs.
How do you use tea tree oil for toenail fungus? While it is important to dilute tea tree oil before applying it to the skin, studies show that using 100 percent tea tree oil is the most effective way to treat nail fungus. Apply a drop or two of oil to the affected nail once or twice daily, while carefully avoiding the surrounding skin to prevent irritation.
How do you use tea tree oil for dandruff? To help control dandruff flakes, use a shampoo that contains 5 percent tea tree oil. Alternatively, try adding 5 to 10 drops of tea tree essential oil to your current shampoo bottle and shake vigorously. Massage into your scalp gently and rinse thoroughly.
How do you use tea tree oil for lice? Research is ongoing to determine the specific dose that is clinically effective. Some clinical trials have used a dose of 1 to 10 percent tea tree oil in a shampoo or gel formula. These mixtures were applied to participants’ skin at least once a day for as long as four weeks. Seek the advice of a medical professional for guidance.
How long does it take for tea tree oil to work? It depends on what is being treated. According to studies, when applied twice daily, 5 percent tea tree oil reduces acne after 45 days; Topical application of 100 percent tea tree oil solution, twice a day for six months, can help treat nail fungus; Application of 25 percent or 50 percent tea tree oil solution for 4 weeks can relieve symptoms and help clear up athlete’s foot.
How should tea tree oil be stored? Tea tree oil can oxidize when exposed to too much light and air, resulting in the breakdown of the oil and rendering it ineffective. It should be kept in a dark glass bottle and stored in a cool, dark place away from sunlight to maintain its efficiency.
How long does tea tree oil last? The oil should last one to two years if it is kept in a cool, dark place and is not exposed to sunlight. Follow the timeframe recommended on the label.
Tea tree oil is an essential oil that is regarded for its broad-spectrum antimicrobial activity and anti-inflammation properties. Derived from the Australian Melaleuca alternifolia plant, it is applied topically for the treatment of acne, athlete’s foot, lice, nail fungus, cold sores and warts.
It is generally safe when used topically, but it can cause skin irritation (itching, redness, burning, swelling and dryness), especially when used in its pure form. To prevent adverse skin reactions, it should be diluted with a carrier oil.
Tea tree oil can be harmful if swallowed.
Although tea tree oil has been used as a traditional medicine in Aboriginal communities for centuries, clinical trials proving its efficacy are lacking. Further research will shed light on its efficacy and safety.