Tea Tree Oil

Q: Does tea tree oil help acne?

Modestly, on current evidence. A 2026 meta-analysis of 7 studies (445 patients) found lower acne severity than controls, and a 5% gel worked more slowly than benzoyl peroxide with fewer side effects.

Q: Can tea tree oil be swallowed?

No. Swallowing it can cause confusion, unsteadiness, inability to walk and coma, and a child swallowing it needs emergency care.

Q: Does it work for athlete's foot or nail fungus?

It eased athlete's foot symptoms in two trials, but cleared the fungus in only one. For nail fungus, NCCIH says the evidence is too limited to draw conclusions.

Q: Can tea tree oil cause breast growth in boys?

Case reports suggest it can. Three prepubertal boys developed breast enlargement while using skin products containing lavender and tea tree oils, and it went away after the products were stopped. LactMed notes more such reports, though their relevance has been questioned.

Q: Does tea tree oil interact with medicines?

No interactions are reported in the EU herbal monograph, and NCCIH lists none, but interaction studies are lacking. NCCIH advises anyone taking a medicine to talk with a health care provider before using any herbal product.

Q: Why does tea tree oil irritate my skin?

Irritation and allergic dermatitis are its main side effects, more likely with strong concentrations and with old oil exposed to heat, light or air.

Q: Is tea tree oil shampoo useful for dandruff?

One 126-person trial found a 5% shampoo used daily for 4 weeks improved dandruff scores more than placebo (41% vs 11%). The trial was funded by a tea tree oil research institute.

Also called Melaleuca alternifolia, melaleuca oil, tea tree essential oil, Melaleucae aetheroleum, terpinen-4-ol.

Best grade C across 7 graded outcomes Botanical Last checked Oct 21, 2026

The short answer

From 14 sources

Tea tree oil is a topical essential oil. Small trials and a 2026 meta-analysis of 445 patients suggest a modest effect on mild to moderate acne, and single trials report benefits for dandruff and athlete's foot symptoms. It must never be swallowed: oral use can cause confusion and coma. Skin irritation and allergy are the usual side effects.

Every graded outcome on this page

7 rows · line = participants

Grade CAcne severityAcnen 445
Grade CAthlete's foot (interdigital tinea pedis): clinical response and fungal clearanceAthlete's footn 158
Grade CDandruff severity (quadrant-area-severity score)Dandruffn 126
Grade CInflamed and non-inflamed acne lesions vs benzoyl peroxideAcnen 124
Grade CToenail fungus (onychomycosis) vs clotrimazoleNail fungusn 117
Grade CAthlete's foot: fungal clearance and symptoms vs tolnaftateAthlete's footn 104
Grade CAcne lesion count and severity indexAcnen 60
4 more graded outcomes, in the evidence chapter

Key facts

What it is: An essential oil steam-distilled from the leaves of Melaleuca alternifolia, mostly produced in Australia¹
Top studied outcome: Acne severity: modestly lower than controls across 7 studies and 445 patients (pooled OR 0.74), grade C³
Never swallow it: Oral use can cause confusion, unsteadiness, inability to walk and coma; ingestion by a child is a medical emergency^1,2
Side effects: Redness, itching, burning and allergic contact dermatitis; old or oxidised oil is more likely to irritate^1,2
Research quality: A 2023 review of 46 randomized trials rated the evidence poor to modest overall; it was funded by AgriFutures Australia, a rural research body, and the tea tree industry association ATTIA gave access to its literature database¹⁰

What it is

Tea tree oil is the steam-distilled essential oil of the Australian Melaleuca alternifolia leaf, used only on the skin.

How it works

Proposed

Tea tree oil has antimicrobial and antifungal activity in laboratory tests, including against the yeast linked to dandruff and the fungi behind athlete's foot. This is the proposed basis for its skin uses; human data on how it works are limited.^6,7

Forms, side by side

3 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.

Tea Tree Oil forms compared

3 forms

Tea Tree Oil forms compared: 3 forms by 3 attributes. Empty cells are labelled No data yet, or Not graded in the evidence row.
3 forms	Gels, creams and washes (5% to 10%)	Shampoo (5%)	Concentrated or undiluted oil (25% to 100%)
Absorption in people	Applied to skin, not swallowed.¹	Applied to scalp and rinsed off.⁶	Applied to skin or nails, not swallowed.²
GI tolerance	Redness and irritation in some people; rare burn-like reactions are listed by the EU monograph.^1,2	No adverse effects in the 4-week dandruff trial.⁶	Side effects were mostly minor in trials except at concentrations of 25% or more; 3.8% developed moderate to severe dermatitis with 25% to 50% solutions.^7,10
Studied for	Acne (5% gel), athlete's foot (10% cream)	Mild to moderate dandruff	Athlete's foot and toenail fungus

Gels, creams and washes (5% to 10%)
Absorption in people
Applied to skin, not swallowed.¹
GI tolerance
Redness and irritation in some people; rare burn-like reactions are listed by the EU monograph.^1,2
Studied for
Acne (5% gel), athlete's foot (10% cream)
Shampoo (5%)
Absorption in people
Applied to scalp and rinsed off.⁶
GI tolerance
No adverse effects in the 4-week dandruff trial.⁶
Studied for
Mild to moderate dandruff
Concentrated or undiluted oil (25% to 100%)
Absorption in people
Applied to skin or nails, not swallowed.²
GI tolerance
Side effects were mostly minor in trials except at concentrations of 25% or more; 3.8% developed moderate to severe dermatitis with 25% to 50% solutions.^7,10
Studied for
Athlete's foot and toenail fungus

What the human research says

Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.

Trial map

7 graded outcomes, largest study first

7 graded outcomes: 5 improved, 2 mixed. The largest, a 2026 meta-analysis of 445 people on acne severity, found an improvement.

By sizeTable

1Acne severity

Improved · Grade C · Meta-analysis, 445 people, 2026

Patients with acne in 7 clinical studies

Dose, result and source

Every graded outcome on this page, largest study first
Outcome	Found	People	Study	Who was studied
Acne severity	Improved	445	Grade C · Meta-analysis, 2026	Patients with acne in 7 clinical studies
Athlete's foot (interdigital tinea pedis): clinical response and fungal clearance	Improved	158	Grade C · RCT, 2002	Patients with interdigital tinea pedis confirmed by microscopy (Australia)
Dandruff severity (quadrant-area-severity score)	Improved	126	Grade C · RCT, 2002	People aged 14 and older with mild to moderate dandruff (Australia)
Inflamed and non-inflamed acne lesions vs benzoyl peroxide	Improved	124	Grade C · RCT, 1990	Patients with mild to moderate acne (Australia)
Toenail fungus (onychomycosis) vs clotrimazole	Mixed	117	Grade C · RCT, 1994	Patients with culture-proven distal subungual onychomycosis (U.S.)
Athlete's foot: fungal clearance and symptoms vs tolnaftate	Mixed	104	Grade C · RCT, 1992	Patients with tinea pedis who completed the trial (Australia)
Acne lesion count and severity index	Improved	60	Grade C · RCT, 2007	Adults with mild to moderate acne vulgaris (Iran)

Every graded row

7 rows

Form tested

Showing 7 of 7 outcomes. Human trials only.

Grade CAcne severityAcnepooled OR 0.74Meta-analysis · 7 studies
n 445 · 2026

Improved Tea tree oil was associated with a modest reduction in acne severity compared with controls (pooled OR 0.74, 95% CI 0.63 to 0.88). Adverse events were mostly local and mild; the authors call for larger, standardized trials.

Design: Meta-analysis, 7 studies, n = 445, 2026
Population: Patients with acne in 7 clinical studies
Form: Topical tea tree oil preparations
Dose: Varied across studies
Duration: Varied
Source: Reference 3 · PubMed 42098589 (opens PubMed)

Grade CAthlete's foot (interdigital tinea pedis): clinical response and fungal clearanceAthlete's footImprovedRCT
n 158 · 2002

Improved Marked clinical response in 72% (25%) and 68% (50%) vs 39% on placebo; fungal cultures turned negative in 64% with 50% oil vs 31% on placebo. Four patients (3.8%) on tea tree oil developed moderate to severe dermatitis that resolved after stopping.

Design: RCT, n = 158, 2002
Population: Patients with interdigital tinea pedis confirmed by microscopy (Australia)
Form: 25% or 50% tea tree oil solution vs placebo
Dose: Applied twice daily
Duration: 4 weeks
Source: Reference 7 · PubMed 12121393 (opens PubMed)

Grade CDandruff severity (quadrant-area-severity score)DandruffImprovedRCT
n 126 · 2002

Improved Severity scores improved 41% with tea tree oil vs 11% with placebo (P < .001); itchiness and greasiness improved, scaliness did not reach significance. No adverse effects were reported.

Design: RCT, n = 126, 2002
Population: People aged 14 and older with mild to moderate dandruff (Australia)
Form: 5% tea tree oil shampoo vs placebo shampoo
Dose: Daily use
Duration: 4 weeks
Source: Reference 6 · PubMed 12451368 (opens PubMed)

Grade CInflamed and non-inflamed acne lesions vs benzoyl peroxideAcneImprovedRCT
n 124 · 1990

Improved Both products reduced inflamed and non-inflamed lesions; tea tree oil acted more slowly but caused fewer side effects.

Design: RCT, n = 124, 1990
Population: Patients with mild to moderate acne (Australia)
Form: 5% tea tree oil gel vs 5% benzoyl peroxide lotion
Dose: 5% gel applied topically
Duration: Not stated in the abstract
Source: Reference 5 · PubMed 2145499 (opens PubMed)

Grade CToenail fungus (onychomycosis) vs clotrimazoleNail fungusMixedRCT
n 117 · 1994

Mixed Results were similar and modest in both groups: negative fungal cultures 18% (tea tree oil) vs 11% (clotrimazole); partial or full clinical resolution 60% vs 61%.

Design: RCT, n = 117, 1994
Population: Patients with culture-proven distal subungual onychomycosis (U.S.)
Form: 100% tea tree oil vs 1% clotrimazole solution, with debridement
Dose: Applied twice daily
Duration: 6 months
Source: Reference 9 · PubMed 8195735 (opens PubMed)

Grade CAthlete's foot: fungal clearance and symptoms vs tolnaftateAthlete's footMixedRCT
n 104 · 1992

Mixed Fungal cultures turned negative with tolnaftate in 85%, tea tree oil 30% and placebo 21% (tea tree oil no better than placebo). Scaling, inflammation, itching and burning improved more with tea tree oil than placebo.

Design: RCT, n = 104, 1992
Population: Patients with tinea pedis who completed the trial (Australia)
Form: 10% tea tree oil cream vs 1% tolnaftate vs placebo cream
Dose: 10% cream
Duration: Not stated in the abstract
Source: Reference 8 · PubMed 1303075 (opens PubMed)

Grade CAcne lesion count and severity indexAcneImprovedRCT
n 60 · 2007

Improved Tea tree oil gel improved total lesion count and acne severity index significantly more than placebo (3.55 and 5.75 times more effective, respectively). Side effects were similar and tolerable in both groups.

Design: RCT, n = 60, 2007
Population: Adults with mild to moderate acne vulgaris (Iran)
Form: 5% tea tree oil gel vs placebo gel
Dose: 5% gel applied topically
Duration: 45 days
Source: Reference 4 · PubMed 17314442 (opens PubMed)

What the numbers add up to

Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.

Symptom relief is not the same as clearing fungus

In the 1992 athlete's foot trial, tea tree oil eased itching and scaling like tolnaftate but cleared the fungus no better than placebo.⁸

Low fungal clearance in nail fungus

After 6 months of twice-daily undiluted oil, fungal cultures were cleared in 18% of patients, against 11% with clotrimazole.⁹

Studied doses

Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.

Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.

Doses studied in human trials

Doses studied in human trials ranged from a 5% gel or shampoo for 4 to about 6 weeks (acne, dandruff) to 25% to 50% solutions twice daily for 4 weeks (athlete's foot) and undiluted oil twice daily for 6 months (toenail fungus). All were applied to the skin, never swallowed.^4,6,7,9

Interactions and safety

Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.

Interactions

0 agents

None found in our sources.

Check with what you take

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Add what you take. We list every interaction our evidence profiles cite between Tea Tree Oil and your picks, and between your picks.

Add a supplement or medicine

Most cited:

Add a supplement or medicine you take to check it against Tea Tree Oil.

Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.

Who should be careful

7 groups

Swallowing or inhaling it: Tea tree oil should never be swallowed, including mouthwashes that contain it; oral use can cause confusion, unsteadiness, inability to walk and coma. The EU monograph also rules out oral and inhaled use.^1,2
Children: Use under 12 has not been established (EU monograph), and accidental ingestion by a child is a medical emergency needing hospital care. In published case reports, a 17-month-old became ataxic and drowsy after swallowing less than 10 mL, and a 4-year-old became unsteady within 30 minutes of swallowing a small amount, then unresponsive, and needed a breathing tube.^2,13,14
Boys before puberty: Breast enlargement in three otherwise healthy prepubertal boys coincided with repeated use of skin products containing lavender and tea tree oils and resolved after the products were stopped. LactMed notes numerous such reports in boys; their relevance has been questioned and not confirmed by further testing.^12,11
Allergy to tea tree oil or colophony: Contraindicated with hypersensitivity to tea tree oil or colophony (rosin). Stop if a rash develops.²
Eyes and ears: The EU monograph says not to use it in the eyes or ears.²
Pregnancy and breastfeeding: NCCIH says topical products may be safe during pregnancy and breastfeeding; the EU monograph, citing a lack of data, does not recommend use. LactMed reports no data in nursing mothers or infants and advises against applying it around the breast unless it is thoroughly removed before nursing. Oral use is never appropriate.^1,2,11
People using other medicines: The EU monograph reports no interactions with medicines, and none are listed by NCCIH; interaction studies are lacking.^2,1

Safety

4 notes

Skin-only use; swallowing it is dangerous.

Skin reactions: Smarting, itching, burning, redness, swelling and allergic contact dermatitis are reported; rare burn-like reactions occur.²
Old oil: Oxidised oil is more likely to sensitise skin; the EU monograph advises air-tight containers protected from light and heat.^1,2
Higher strengths: Side effects in trials were minor except where the oil was used at 25% or higher.¹⁰
Accidental ingestion: Can cause central nervous system depression and muscle weakness; in children it requires immediate hospital care.²

How to read the label

What to check on the Supplement Facts panel.

How to read the label

3 checks

Label strength vs trial strength

Acne and dandruff trials used 5% products, athlete's foot trials 10% to 50%. A bottle of pure oil is far stronger than any acne trial product.^4,6,7,8

Storage

Keep it in an air-tight, dark container away from heat; oxidised oil irritates skin more.²

Not for mouth use

Tea tree oil mouthrinses should not be swallowed, and their benefit for gums and breath is uncertain.¹

Frequently asked questions

Short answers to common questions; the numbers link to the sources below.

Common questions

7 answers

Does tea tree oil help acne?

Modestly, on current evidence. A 2026 meta-analysis of 7 studies (445 patients) found lower acne severity than controls, and a 5% gel worked more slowly than benzoyl peroxide with fewer side effects.^3,5

Can tea tree oil be swallowed?

No. Swallowing it can cause confusion, unsteadiness, inability to walk and coma, and a child swallowing it needs emergency care.^1,2

Does it work for athlete's foot or nail fungus?

It eased athlete's foot symptoms in two trials, but cleared the fungus in only one. For nail fungus, NCCIH says the evidence is too limited to draw conclusions.^1,7,8

Can tea tree oil cause breast growth in boys?

Case reports suggest it can. Three prepubertal boys developed breast enlargement while using skin products containing lavender and tea tree oils, and it went away after the products were stopped. LactMed notes more such reports, though their relevance has been questioned.^12,11

Does tea tree oil interact with medicines?

No interactions are reported in the EU herbal monograph, and NCCIH lists none, but interaction studies are lacking. NCCIH advises anyone taking a medicine to talk with a health care provider before using any herbal product.^2,1

Why does tea tree oil irritate my skin?

Irritation and allergic dermatitis are its main side effects, more likely with strong concentrations and with old oil exposed to heat, light or air.^1,2,10

Is tea tree oil shampoo useful for dandruff?

One 126-person trial found a 5% shampoo used daily for 4 weeks improved dandruff scores more than placebo (41% vs 11%). The trial was funded by a tea tree oil research institute.⁶

Sources

14 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.

Sources cited on this page

14 sources

1Tea Tree Oil (last updated April 2025)Fact sheet NCCIH, 2025 · nccih.nih.gov
2European Union herbal monograph on Melaleuca alternifolia (Maiden and Betch) Cheel, M. linariifolia Smith, M. dissitiflora F. Mueller and/or other species of Melaleuca, aetheroleum (EMA/HMPC/320930/2012)Guideline European Medicines Agency (HMPC), 2015 · ema.europa.eu
3Efficacy and Safety of Melaleuca alternifolia (Tea Tree) Oil for Acne-A Systematic Review and Meta-Analysis.Meta-analysis Phytother Res, 2026 · PMID 42098589
4The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: a randomized, double-blind placebo-controlled study.RCT Indian J Dermatol Venereol Leprol, 2007 · PMID 17314442
5A comparative study of tea-tree oil versus benzoylperoxide in the treatment of acne.RCT Med J Aust, 1990 · PMID 2145499
6Treatment of dandruff with 5% tea tree oil shampoo.RCT J Am Acad Dermatol, 2002 · PMID 12451368
7Treatment of interdigital tinea pedis with 25% and 50% tea tree oil solution: a randomized, placebo-controlled, blinded study.RCT Australas J Dermatol, 2002 · PMID 12121393
8Tea tree oil in the treatment of tinea pedis.RCT Australas J Dermatol, 1992 · PMID 1303075
9Comparison of two topical preparations for the treatment of onychomycosis: Melaleuca alternifolia (tea tree) oil and clotrimazole.RCT J Fam Pract, 1994 · PMID 8195735
10Efficacy and safety of Melaleuca alternifolia (tea tree) oil for human health-A systematic review of randomized controlled trials.Systematic review Front Pharmacol, 2023 · PMID 37033604
11Tea Tree Oil. Drugs and Lactation Database (LactMed)Database National Institute of Child Health and Human Development, 2024 · ncbi.nlm.nih.gov
12Prepubertal gynecomastia linked to lavender and tea tree oils.Observational N Engl J Med, 2007 · PMID 17267908
13Melaleuca oil poisoning in a 17-month-old.Observational Vet Hum Toxicol, 1995 · PMID 8588296
14Ingestion of tea tree oil (Melaleuca oil) by a 4-year-old boy.Observational Pediatr Emerg Care, 2003 · PMID 12813303

What changed

Every dated change to this page: what changed, who made it and why.

Change log

3 entries

Dated changes to this page
Date	Change	Who and why
Oct 21, 2026who should be careful, insights, FAQ, related links, sources	Added LactMed (NBK501884, revised 2024) to the breastfeeding note; a 'boys before puberty' note from the 2007 case series (PMID 17267908); two child-ingestion case reports (PMIDs 8588296, 12813303); a medicines note and FAQ (EU monograph: no interactions reported; NCCIH lists none); a breast-growth FAQ; a nail-fungus insight; links to lavender and the hair and skin hub. Interaction table left empty after checking the EU monograph, NCCIH and LactMed. PubMed searched for 2023–2026 meta-analyses and RCTs: the 2026 acne meta-analysis remains the newest skin row; a 2024 gum-disease meta-analysis (PMID 38864380) and a 2023 Demodex meta-analysis (PMID 36310014) report no tea tree participant totals in their abstracts and were not added. Fact-checked against the sources; corrected: nail fungus insight now gives negative fungal cultures as 18% of patients, not of toenails; the medicines FAQ now reflects that NCCIH's advice is aimed at people taking medicines.	Writer: Kymata Health EditorialTrigger: A–Z page audit
Oct 14, 2026all	Initial editorial evidence review (first draft). Every PMID checked against NCBI E-utilities esummary (title and year) and each cited abstract read; numbers taken from the abstracts. No retractions or errata linked to the cited PMIDs. Funding: the 2002 dandruff trial was funded by the Australian Tea Tree Oil Research Institute (stated in the journal article), and an institute researcher co-authored the 2002 athlete's foot trial; the 2026 meta-analysis was publicly funded. Safety, interaction and pregnancy text come only from NCCIH and the EMA herbal monograph (no interactions reported). No product links.	Writer: Kymata Health EditorialTrigger: new page
Oct 14, 2026evidence and safety	Adversarial review: disclosed that the 2023 systematic review (PMID 37033604) was funded by AgriFutures Australia (grant PRJ-012616) with literature access from ATTIA Ltd; its authors declared no conflicts.	Writer: Kymata Health EditorialTrigger: adversarial review

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