Tea tree oil (Melaleuca alternifolia [Maiden & Betche] Cheel)
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| Tea tree
oil |
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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 in vitro studies have demonstrated
antimicrobial properties of tea tree oil (likely attributable to the
constituent terpinen-4-ol), only a small number of randomized, controlled
human trials have been published. Human studies have focused on the use of
topical tea tree oil for fungal infections (including onychomycosis and tinea
pedis), acne, and vaginal infections. However, no definitive evidence exists
for the use of tea tree oil in any of these conditions, and further study is
warranted.
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Tea tree oil should be avoided orally, as reports of toxicity after oral
ingestion have been published. When used topically, 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.
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Australian tea tree oil, Bogaskin® (veterinary formulation), breathaway,
Burnaid® (40mg/g of tea tree oil and 1mg/g of triclosan), cymene, M.
alternifolia , malaleuca, Melaleuca Alternifolia Hydrogel® (burn
dressing), melaleucae, melaleuca oil, oil of mela-leuca, oleum, Oleum
melaleucae, T36-C7, tea tree oil, Tebodont®, teebaum, terpinen,
terpinen-4-ol, terpinenol-4, ti tree, TTO.
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Note: Should not be confused with cajeput oil, niauouli oil, kanuka oil, or
manuka oil obtained from other Melaleuca species.
These uses have been tested in humans or animals. Safety
and effectiveness have not always been proven. Some of these conditions are
potentially serious, and should be evaluated by a qualified healthcare provider.
| Uses based on scientific evidence |
Grade* |
| Acne vulgaris
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.
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| Allergic skin reactions
One small study shows that topical tea tree oil may reduce
histamine-induced skin inflammation. Further research is needed to
confirm these results.
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| Athlete's foot (tinea pedis)
Preliminary studies report tea tree oil to have activity against several
fungal species. However, at this time there is not sufficient
information to make recommendations for or against the use of tea tree
oil on the skin for this condition.
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| Dandruff
Preliminary 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.
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| Fungal nail infection (onychomycosis)
Although tea tree oil is thought to have activity against several fungus
species, there is not sufficient information to make recommendations for
or against the use of tea tree oil on the skin for onychomycosis.
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| Genital herpes
Tea tree oil has activity against some viruses in laboratory studies,
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 sufficient information to make a recommendation for or against this
use of tea tree oil.
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| 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 plus a
tea tree body wash may treat colonization by this bacteria. However,
there is currently not enough information from studies in humans to make
recommendations for or against this use of tea tree oil.
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| Plaque/gingivitis
Study results on the effects of tea tree oil mouthwash on gum
inflammation and plaque are mixed. Further research is needed before a
conclusion can be drawn.
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| Thrush (Candida albicans of the mouth)
In laboratory studies, tea tree oil can kill fungus and yeast such as Candida
albicans. However, at this time there is not enough information
available from studies in humans 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.
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| Vaginal infections (yeast and bacteria)
In laboratory studies, tea tree oil can kill yeast and certain bacteria . However,
at this time there is not enough information available from studies in
humans 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.
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*Key to grades
A: Strong scientific evidence for this use;
B: Good scientific evidence for this use;
C: Unclear scientific evidence for this use;
D: Fair scientific evidence against this use;
F: Strong scientific evidence against this use.
Grading rationale
Uses based on tradition or theory
The below uses are based on tradition or scientific theories. They often
have not been thoroughly tested in humans, and safety and effectiveness have
not always been proven. Some of these conditions are potentially serious, and
should be evaluated by a qualified healthcare provider.
Anti-inflammatory, antihistamine, antioxidant, antiseptic, body odor, boils,
bronchial congestion, bruises, burns, carbuncles, colds, contraction cessation,
corns, cough, eczema, furuncles, gangrene, immune system deficiencies, impetigo,
insect bites/stings, lice, lung inflammation, melanoma, mouth sores, muscle and
joint pain, nose and throat irritation, periodontal disease, psoriasis,
ringworm, root canal treatment, scabies, sinus infections, skin
ailments/infections, solvent, sore throat, tonsillitis, vulvovaginitis, warts,
wound healing.
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)
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Tea tree oil has been used in gels, creams shampoo, body washes and in
tinctures or extracts. Most doses used in studies are applied topically (on
the skin). These doses have not necessarily been proven effective or safe.
While 100% tea tree oil is sometimes used (ex. for fungal nail infections), it
is often diluted with inactive ingredients. Typically, preparations contain
about 4-5% tea tree oil and are used daily for four weeks to six months
depending on condition. 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.
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Tea tree oil 5% gel has been applied to acne-prone areas of the skin daily.
For athlete's foot (tinea pedis), 10% tea tree oil cream, applied twice daily
to the feet after they have been thoroughly washed and dried or 25-50% tea
tree oil solution applied twice daily to the affected area for 4 weeks has
been studied. For genital herpes, a 6% tea tree oil gel has been used.
Children (younger than 18 years)
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There is insufficient research to recommend the safe use of tea tree oil in
children.
The U.S. Food and Drug Administration does not strictly
regulate herbs and supplements. 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.
Allergies
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There are multiple 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. People with a history of allergy to tincture of benzoin
or colophony (rosin) should not use tea tree oil products because
cross-reactions have been reported.
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Use cautiously if allergic to eucalyptol as many tea tree preparations contain
eucalyptol.
Side Effects and Warnings
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Tea tree oil taken by mouth is 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.
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When used on the skin, tea tree oil may cause allergic rash, redness,
blistering, and itching. Use of tea tree oil inside of the mouth or eyes can
cause irritation. One report describes a person with long-standing eczema (atopic
dermatitis) who developed a severe flare after applying 100% tea tree oil
mixed in honey to the skin. 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
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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.
Most herbs and supplements have not been thoroughly
tested for interactions with other herbs, supplements, drugs, or foods. The
interactions listed below are based on reports in scientific publications,
laboratory experiments, or traditional use. 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.
Interactions with Drugs
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Tea tree oil skin products may result in drying of the skin, and may worsen
the drying caused by skin treatments such as tretinoin (Retin-A®), benzoyl
peroxide, salicylic acid, or isotretinoin (Accutane®, taken by mouth).
Interactions with Herbs and Supplements
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Not enough scientific information is available.