INGREDIENT · ESSENTIAL OIL
Tea tree oil in skincare: acne, allergy and EU limits
Tea tree oil has real antimicrobial chemistry, an acne trial or two, and a track record of causing allergic reactions when it ages. The EU only recently decided how much is acceptable.
You may see it written as
- Tea Tree Oil
- Melaleuca Alternifolia Leaf Oil
What tea tree oil is
Tea tree oil is an essential oil steam-distilled from the Australian plant Melaleuca alternifolia. Its main component terpinen-4-ol has strong antimicrobial and anti-inflammatory properties, and the oil has been reported to act against bacteria, viruses, fungi and protozoa affecting skin and mucosa.1
A 2006 review described close to 80 years of use that suggests topical use is relatively safe, with adverse events that are minor, self-limiting and occasional. It also warned of the downsides: tea tree oil is toxic if swallowed in higher doses and can irritate skin at higher concentrations.2
What the acne evidence is
In a randomised, double-blind trial of 60 patients with mild to moderate acne, a 5% tea tree oil gel or placebo was used over 45 days. The gel was 3.55 times more effective than placebo for total lesion count and 5.75 times for severity, and side effects were similar and tolerable.3
A systematic review of 46 articles across all uses of tea tree oil is less sure. It found oral mouthwashes with 0.2% to 0.5% oil may limit dental plaque, but said more evidence is needed to confirm the benefit for reducing acne lesions and severity.4
Allergy and why age matters
Allergic reactions to tea tree oil occur in predisposed people, and may be due to oxidation products that form when the oil is exposed to light or air. The 2006 toxicity review advises applying only diluted oil, avoiding swallowing it, and using oil that has been stored correctly.2
The EU's safety committee agreed on the sensitisation point. In its 2025 opinion, it said that based on the data provided, tea tree oil is a moderate skin sensitiser, and that the stability of the oil must be maintained in the final product.5
What the EU safety committee decided
Neither region sets a binding cap. EU guidance recommends up to 1% tea tree oil; India has no equivalent guidance.
In October 2025 the committee considered tea tree oil safe as an anti-seborrhoeic and antimicrobial agent in four product types, up to 2.0% in shampoo, 1.0% in shower gel, 1.0% in face wash and 0.1% in face cream. It applies only to oil that conforms to the ISO 4730:2017 composition standard, to dermally applied products for adults, and not to sprays or aerosols that could be inhaled. The assessment also took into account a possible classification as a reproductive toxicant (Repr. 1B).5
That is more specific than the EU guidance of 1% in Snifff's summary above, and newer. We did not find an entry for tea tree oil in the Cosmetics Regulation's annexes of prohibited or restricted substances,6 so the limits above are the safety committee's advice rather than a legal cap.
Tea tree oil in pregnancy and breastfeeding
We found no pregnancy- or lactation-specific evidence for this ingredient.
Evidence on cosmetic products in pregnancy is limited overall, so ask your doctor or midwife about the specific product you use.7
What you will see on the label
On a label, look for Tea Tree Oil and Melaleuca Alternifolia Leaf Oil. Snifff shows it as Moderate risk. For the rest of the formula, see what the score means and how to read the list.
As Snifff shows itTea Tree Oil
Pregnancy and nursing
We found no pregnancy- or lactation-specific evidence for this ingredient.
Regulatory gap
Neither region sets a binding cap. EU guidance recommends up to 1% tea tree oil; India has no equivalent guidance.
Wording as it appears in the extension, which can change between releases.
A FEW MORE ANSWERS
Common questions about tea tree oil
Is tea tree oil good for acne?
A 60-patient trial found a 5% gel 3.55 times more effective than placebo for lesion count,3 but a 2023 review of randomised trials says more evidence is needed.4
Can tea tree oil cause allergy?
Yes. The EU safety committee called it a moderate skin sensitiser,5 and allergic reactions may be due to oxidation products formed as the oil ages.2
How much tea tree oil is safe in skincare?
In its 2025 opinion, the EU safety committee considered up to 2.0% in shampoo, 1.0% in shower gel, 1.0% in face wash and 0.1% in face cream safe for adults, for oil meeting a composition standard.5
Is tea tree oil safe in pregnancy?
Snifff found no pregnancy-specific evidence for Tea tree oil. Ask your doctor or midwife about the product you use.
WHERE THIS COMES FROM
Sources
- A review of applications of tea tree oil in dermatologyPazyar N, et al. · International Journal of Dermatology · 2013
- A review of the toxicity of Melaleuca alternifolia (tea tree) oilHammer KA, et al. · Food and Chemical Toxicology · 2006
- The efficacy of 5% topical tea tree oil gel in mild to moderate acne vulgaris: a randomized, double-blind placebo-controlled studyEnshaieh S, et al. · Indian Journal of Dermatology, Venereology and Leprology · 2007
- Efficacy and safety of Melaleuca alternifolia (tea tree) oil for human health: a systematic review of randomized controlled trialsKairey L, et al. · Frontiers in Pharmacology · 2023
- Opinion on tea tree oil (Melaleuca alternifolia leaf oil)Scientific Committee on Consumer Safety, European Commission · 2025 · SCCS/1681/25, adopted 30 October 2025
- Regulation (EC) No 1223/2009 on cosmetic products (consolidated text, version of 1 September 2025)European Union · 2009
- Cosmetic dermatology in pregnancy and lactation: a risk-benefit framework for clinical practiceKovacs T, et al. · International Journal of Dermatology · 2026
This page explains an ingredient. It is not medical advice, and it is not an assessment of any product. If you are pregnant, breastfeeding, or have a skin condition, ask your doctor or pharmacist.