Tea Tree Oil Benefits and Uses

In this Article (Index)

• Where does Tea Tree Oil come from?
• Uses of Tea Tree Oil
• Tea Tree Oil for skin conditions
• Treatment of nail fungal infections (Onychomycosis)
• Athlete's Foot
• Ringworm
• Antimicrobial and disinfectant
• Hand sanitizer
• Molluscum Contagiosum
• Oral Hygene
• Cold Sores
• Lice
• Dandruff
• What Do We Know About Tea Tree Oil's Safety?

Tea Tree Oil

The origin of Tea Tree Oil

Tea tree oil, also known as tea tree, tea tree essential oil or Australian tea tree oil, TTO for short, is obtained from a plant that grows in southeastern Australia.

Tea tree's scientific name is Melaleuca alternifolia, and is a member of the Melaleuca genus that belongs to the Myrtaceae family, or myrtle. It can grow into a tree 15 to 25 feet tall (5 to 8 metes) (1).

Like all other members of the myrtle family (that includes the clove, allspice, and eucalyptus), it contains essential oils. These are extracted by distilling the leaves and the tender terminal branches with steam. The condensed vapor yields a clear to pale yellow oil known as Tea Tree Oil. 50 to 100 lb. of plant material are processed to obtain one pound of oil.

Chemistry

Tea Tree Oil is composed of over 100 different molecules, most of them are terpene hydrocarbons and associated alcohols. These are volatile components and they give it its particular odor.

The antimicrobial properties of the oil are attributed to terpinen-4-ol, one of its major components. Another component is 1,8-cineole. For many years it was erroneously considered to be a skin irritant, but it isn't. α-Terpinene is one of its components responsible for its antioxidant activity (21).

Traditional Folk Uses

The Bundjalung people of southeastern Queensland and northwestern New South Wales used the plant to treat skin ailments. They have a myth involving their legendary Princess Eelemani, who asked the Gods for help on a long journey along the coast, and they gave her some magical seeds that she sowed along the trails she trekked. They grew into trees that guided her at night with their gray-white bark, and whose leaves had magical properties (2).

The Australian Aboriginal people crushed the leaves of the tea tree plant to release its oil, and inhaled it to treat colds and coughs. They also applied it as a poultice on wounds. They brewed an infusion to treat sore throats or applied the liquid topically to the skin to treat insect bites, stings and minor wounds (2).

It gets its name because it was used to brew tea during Captain Cook's voyages to Australia and New Zealand. Cook wrote: "We at first made our beer of a decoction of the spruce leaves; but, finding that this alone made it too astringent, we afterwards mixed with it an equal quantity of the tea plant (a name it obtained in my former voyage, from our using it as a tea then, as we also did now), which partly destroyed the astringency of the other, and made the beer exceedingly palatable" (3).

Uses of Tea Tree Oil

Tea Tree Oil is promoted as a natural herbal remedy for external use to treat skin affections such as fungal infections (nail fungus, athlete's foot), acne, lice, mite infections in the eyelids, insect bites and oral hygene.

Tea Tree Oil should not be swallowed, ingested or used (like Cook did) in teas or infusions. Read about its side effects and oral toxicity.

How Much Do We Know about its effectiveness?

Several studies involving a limited number of subjects have been conducted to study the use of TTO in topical use (applying the oil to the skin), or as part mouth washes for oral hygene. They have shown that it has promising possibilities, but the small scale trials can only provide inconclusive support to its purported benefits.

Tea Tree Oil for skin conditions

Is tea tree oil antifungal?

Yes, it is.
Several studies have shown that tea tree oil inhibits the growth of fungi and has fungicidal properties.

Onychomycosis affects toenails and fingernails, and is caused by fungi of different species, some of them are dermatophytes of the Trichophyton like the Trichophyton rubrum. Non-dermatophyte molds are caused by other species such as Scopulariopsis brevicaulis, Fusarium spp., and Aspergillus spp.. There are more types of molds and yeasts including Candida albicans, but these are less frequent, mostly affecting immunodepressed and diabetic patients.

Skin and nail fungi

Hammer et al. (2002) showed that "tea tree oil has fungicidal activity... Based on both its inhibitory and fungicidal action, tea tree oil may be a useful agent for treating dermatophyte infections" (4).

Dermatophytes are a group of fungi that infect tissue containing keratine, like the hair, nails and skin.

Another trial conducted by Diane C. Homeyer et al. (2015) demonstrated the antifungal activity of tea tree oil against "filamentous fungi associated with Invasive fungal wound infections (IFIs)" with very small side effects "indicat[ing] a potential use of TTO as topical treatment of IFIs." (5).

Treatment of nail fungal infections (Onychomycosis)

Hamid et al. (2018) (6) looked into the effects of tea tree oil in Onychomycosis, a type of fungal infection that affects toenails or fingernails. They conducted a six-month-long randomized double blind trial involving 66 subjects. They applied 100% pure TTP topically and the outcome was "27% of patients were completely cured, 65% were partially cured and 8% had no response." They concluded that "TTO may play a role in treatment of onychomycosis without side effects of medications."

Alessandrini et al. (2020) (7) evaluated a topical antifungal containing tea tree oil and other essential oils (lime, and oregano) plus vitamin E. The study also lasted for 6 months, and involved 20 patients with daily application of the product on the nail fungus (caused by dermatophytes and non-dermatophyte molds). And was followed up for another 6 months.
The outcome was that "the majority of patients achieved a complete cure of onychomycosis (78.5%).... No side effects were recorded."

Athlete's Foot

Athlete's Foot is caused by a dermatophyte fungus, Tinea pedis. There is limited evidence supporting a positive antimicotic activity of TTO against T. pedis. Satchell, Saurajen, Bell and Barnetson (2002) (15) conducted a randomized double-blind study involving 158 patients affected by athlete's foot to validate the effects of tea tree oil. They were assigned to three groups receiving either a placebo, 25% or 50% tea tree oil. The affected areas were treated with the topical solution twice a day for 4 weeks.
Whereas only 39% of the placebo group showed a strong response to the treatment, 72% of the 25% TTO and 68% of the 50% TTO groups showed improvement. Regarding the cure rate (one thing is an improvement of the symptoms, another is the elimination of the fungi) 64% of those in the 50% tea tree oil were cured, compared to 31% in the placebo group. Also, 3.8% of the patients developed moderate to severe dermatitis that resolved quickly after suspending the treatment. Read more about TTO's side effects below.

Ringworm

Regarding Tinea corporis the fungus responsible for ringworm, a randomized controlled trial by Pokharel, Yaptinchay and Thaebtharm (2015) (16) found that tea tree oil 50% in a cream base had the same therapeutical effect as regular clotrimazole 1% cream, the normal treatment for ringworm. The study involved sixty patients who applied the treatment twice a day for 4 weeks.

Molluscum Contagiosum

Tea tree oil with added iodine may provide an effective treatment for molluscum contagiosum lesions in young children. (Kairey et al., 2023) (20). This is a viral disease that produces small rounded itchy bumps on the skin

Antimicrobial and disinfectant

In an anecdotical experiment, Fitzpatrick (2019) (8) tested the abilities of TTO to control the growth of five bacteria in Petri disehs found that it inhibited the growth of four out five bacteria tested: Bacillus subtilis, Escherichia coli, Micrococcus roseus, Serratia marcescens, it wasn't effective against Sarcina luteus. Furhtermore this antimicrobial effect was compared to fresh garlic, an industrial quaternary ammonium cleaner and Listerine ® mouthwash finding that it "showed superior results" to all of them. Tea tree oil therefore has a potential use as a surface cleaner.

According to Kairet et al., (2023) topical tea tree oil application therapies "show similar efficacy to standard treatments for decolonizing the body from methicillin-resistant Staphylococcus aureus"(20)

Hand sanitizer

Youn et al., (2021) (9) conducted a random trial involving 112 healthy subjects where they compared the disinfecting abilities of tea tree oil against other common hand santisers (gel with 83% ethanol, foam-type benzalkonium chloride. The team found that this"study confirmed that tea tree oil disinfectant is effective for hand disinfection. Accordingly, tea tree oil disinfectants may be introduced to nursing practice as a new hand hygiene product to prevent and reduce healthcare-associated infections."

The formulation they used include 2 parts of tea tree oil , 2 parts of a solubilizer (to help blend the oil in water), 1 part of glycerin, and 15 parts of sterile distilled water, resulting in a 10% dilution of the TTO.

Oral Hygene

Styudies have shown that tea treee oil can inhibit the growth of microorganisms in the mouth and teeth and therefore act as an aid to prevent caries and peridontal disease.

Gum disease treatment, as a mouthwash

Tea tree oil was tested in a pilot study as a mouthwash for treating gum disease (Ripari et al, 2020)(10). This was a randomized clinical trial involving patients suffering from gingivitis. The tea tree oil was administered in the form of mouthwash and compared with a conventional mouthwash (with 0.12% chlorhexidine). The patients rinsed their mouths using 3 drops of TTO in less than half a glass of water after brushing their teeth three times a day. The authors found that "The comparison showed that tea tree oil offered a better improvement in the evaluation of PI [plaque index], BOP [bleeding on probing], and PD [probing depth]." They concluded that "The results suggest that tea tree oil could be advantageous in cases where patients spend little time on toothbrushing." It also avoids the negative effect of conventional chlorhexidine mouthwash: stained teeth and plaque deposit.

It is worth noting that 18% of the patients usint TTO complained about nausea uring the first days of treatment due to its characteristic smell.

A meta-analysis by Kairey et al., (2023) (20) corroborates its effectiveness as a mouthwash: "mouthwashes with 0.2%–0.5% tea tree oil may limit accumulation of dental plaque. Gels containing 5% tea tree oil applied directly to the periodontium may aid treatment of periodontitis as an adjunctive therapy to scaling and root planing."

Caries treatment

Another study (Patri and Sahu, 2017)(11) tested two herbal agents, tea tree oil and aloe vera and applied them as cavity disinfectants in the treatment of caries, to eliminate any bacteria present in the cavity and minimize the appearance of secondary cavities in the same tooth.
They applied a 1% dilution of TTO using an emulsifying agent (Tween 80) and distilled water, and this was compared with regular 2% chlorhexidine and aloe vera gel.

Bacterial counts before, during and after the procedures showed that 2% chlorhexidine was the most effective disinfectant, followed by TTO and aloe vera in the third place. The authors concluded that "Natural antibacterial agents like tea tree oil and aloe vera could be effectively used as cavity disinfectants which will help in minimizing secondary caries and rendering a long term restorative success."

Oral fungal infections caused by denture use

It has also been tested as an effective inhibitor of the fungus Candida albicans that causes a condition known as dental stomatitis in denture wearers. This provokes redness, swelling, soreness in the mouth and palate. Dalwai et al. (2016) (12) tested tea tree oil as a rinse or denture cleaner and to treat dentures, in comparison to chlorhexidine or fluconazole (an antifungal agent), and found that "Tea tree oil and chlorhexidine gluconate are more effective than fluconazole in inhibiting C. albicans growth on heat-polymerised acrylic resin."

Oral Antimicrobial

It has also been tested and proved effective against a nother microorganism, Enterococcus faecalis that lives inside the teeth: dental pulp, root, nerves and surrounding tissue. It is an endodontic pathogen that is associated to persistent root canal infections and also to failure of root canal treatment. Jianyan et al. (2021), (13) tested it in comparison to chlorhexidine and found that it acts on this particular bacteria destroying its cell membrane, and inhibiting the formation of biofilms and eliminating mature biofilms. Biofilms or plaque are structured aggregations or colonies of bacteria that stick to the surface of teeth and gums in the mouth. Jianyan's study reports that "The effect of TTO was the same as that of 0.2% CHX at some specific concentrations. In summary, TTO has the potential to be effective against E. faecalis infections... [and] be further developed as a novel antibacterial drug."

Cold Sores - oral herpes

TTO has been used to treat Cold sores, blisters on lips and mouth provoked by the Herpes simplex 1 virus. The anti-herpesviral effect was studied in a randomized, placebo controlled trial involving 20 participants where half received a placebo gel and the other half a 6% tea tree oil gel. They applied it 5 times a day.
The tea tree oil gel had a shorter healing time (9 days) vs. 12.5 days for the placebo, and the viral load of their sores was lower too. The study concluded that "Melaleuca alternifolia oil has potential to be a cost effective alternative topical treatment for herpes labialis infections" adding that it has the advantage of being cheaper, acceptable to the patients and " poses little threat of inducing resistance to systemic antiviral agents" (23).

Hair Treatments

Dandruff

In 2002, Satchell et al. (17) tested a shampoo containing 5% tea tree oil against a placebo in a single-blinded randomized clinical trial with 126 patients suffering from mild to moderate dandruff. They washed their hair daily for 4 weeks.
Dandruff is provoked by Pityrosporum ovale, a yeast and tea tree oil proved to be effective in 41% of the 5% TTO shampoo group compared to 11% in the placebo group. It reduced itchiness, greasiness and the quadrant-area-severity score without any adverse effects. The authors concluded that "Five percent tea tree oil appears to effective and well tolerated in the treatment of dandruff".

Lice

Di Campli et al., (2012) (14) explored the efficacy of essential oils in controlling head lice infestation. They took tea tree oil and nerolidol and tested them together and separately against lice and its eggs.
They found that "Tea tree oil was more effective than nerolidol against head lice with 100 % mortality at 30 min and 1% concentration." A 2% concentrate of TTO had a potent ovicidal effect turning half of the eggs non-viable after four days, similar to the effect of a 1% nerolidol application. A promising outlook in the treatment of pediculosis strains resistant to common insecticides used against lice.

What Do We Know About Tea Tree Oil's Safety?

External Use Only - Don't ingest

Like all essential oils, Tea tree oil should not be ingested. Swallowing it can provoke serious symptoms such as confusion, breathing problems, loss of muscle coordination (or ataxia), and even coma (1). No human deaths due to TTO have been reported in the literature, but poisoning of children has occurred, and they recovered without further consequences after adequate medical treatment (19).

Test skin for allergy

Even though most people can apply products containing tea tree oil to their skin, nails and hair without any problems, some may be allergic to it. People with allergy may develop an allergic skin rash (or contact dermatitis) in the area where the product was applied topically.

Patch Test: do a test for sensitive skin applying a small amount of the cosmetic containing the Tea Tree oil it on small areas of your skin first, to see if you experience a skin reaction.

The European Union's Scientific Committee on Consumer Products pointed out that Tea tree oil is a skin sensitiser, that in certain formulations at concentrations of 5% or more, it can induce skin and eye irritation (18).

Its safety during pregnancy or while breastfeeding is not known (1).

Carson, Hammer and Riley (2006) (19) also recommend not applying it on the skin of domestic animals, there has been reports of a cat dying from dermal application of TTO.

Safe Use and Storage

Neat TTO should not be applied to the skin, and commercial products that are correctly formulated and bottled should be the preferred choice.

Sunita Lahkar et al, (2013) recommend using adequate carrier systems. Carrier oils dilute the TTO and may enhance its cosmetic properties. These carriers include: olive oil, jojoba oil, almond oil, and coconut oil. Remember that in contact with the air TTO's components oxidize and degrade.

The irritant components in tea tree oil appear in aged, or incorrectly stored product. Sunlight, oxygen and high temperatures degrade the oil. Plastic bottles as opposed to aluminum or glass vials allow oxygen to oxidize the components, mainly α-Terpinene that degrades rapidly, forming allylic epoxides and p-cymene as the major oxidation products and also hydrogen peroxide. Air-exposure enhances the sensitization potency of α-terpinene (21).