Tea tree oil

Botanical0.5–5%

A native Australian essential oil with a fresh, medicinal scent, used in clarifying skin, scalp and body care.

What it is

Tea tree oil is steam-distilled from the leaves of Melaleuca alternifolia, grown on plantations in northern New South Wales and Queensland. It gives cleansers, body washes and shampoos a fresh, clean feel and is a familiar choice for oily skin and an oily, flaky scalp. The Bundjalung people of northern New South Wales used the crushed leaves long before the oil was distilled.

Good for

Oily skinOily scalpFlaky scalp

How it works

Its main component, terpinen-4-ol, disrupts the cell membranes of microbes in lab studies, which supports a clean, fresh feel on skin and scalp. Lab work also suggests it can calm the look of redness.

Ratings

Evidence

4/5

Extensive lab data and several clinical trials.

Gentleness

3/5

Fine at low levels, but it is a moderate skin sensitiser, more so when oxidised.

Formulation difficulty

3/5

Needs solubilisers in water-based products and protection from air.

Cost

2/5

Moderate, with verified Australian oil costing more than blends.

Popularity

5/5

Used in skin, scalp and body care around the world.

Pairs and cautions

Pairs well with

In a routine. Pairing in one formula depends on matching pH windows.

Take care with

Baby productsCan sensitise skin
Leave-on use near the eyesHarsh on the eye area

Formulations it suits

Body wash Gel and foaming cleanser Shampoo Serum Gel Cream Deodorant stick

Packaging

Regional considerations

Australia	Neat oil is Schedule 6 unless packed at 15 mL or less with a restricted-flow insert and warnings, or at 25 mL or less with a restricted-flow insert, child-resistant closure and warnings; products at 25% or less are unscheduled. 'Antiseptic' or acne-treatment claims make it a TGA medicine.
European Union	The EU is moving to class it a reproductive toxicant; expected limits follow the SCCS: 2% shampoo, 1% body or face wash, 0.1% face cream, adults only, no sprays. Allergens it contains, such as alpha-terpinene, terpinolene and limonene, must be labelled above 0.001% (leave-on) or 0.01% (rinse-off).
United Kingdom	In August 2025 Great Britain's HSE proposed not classifying tea tree oil as a reproductive toxicant for now, pending further assessment, so the EU's expected limits are not set to apply in GB.
China	Listed in China's IECIC as Melaleuca Alternifolia (Tea Tree) Leaf Oil, so it needs no new-ingredient filing with NMPA.

In the lab

Specifications

Typical use level

0.5–5%0525%

Solubility

Oil-soluble

Sensitive to

OxygenLightHeat

Body washes and shampoos use 0.5–2% for a clean, herbal note; leave-on gels and scalp and foot products use 1–5%.

INCI	Melaleuca Alternifolia (Tea Tree) Leaf Oil
Also known as	Melaleuca oil, TTO, Melaleuca alternifolia
Origin	plant-derived

Lab notes

Solubility and phase

Oil phase, or solubilise into water-based products with polysorbate 20, PEG-40 hydrogenated castor oil or a natural solubiliser.

Stability

Add below 40 °C with an antioxidant, and store the oil cool, dark and in full containers. Oxidation raises p-cymene and peroxides, and aged, oxidised oil is harsher on skin and a known sensitiser.

Regulatory, Australia

Specify oil to ISO 4730:2025, which replaced the 2017 edition (terpinen-4-ol 35–48%, 1,8-cineole 10% max) in June 2025; it is a cosmetic ingredient (AICIS). Poisons Standard Schedule 6 applies except to preparations with 25% or less and to small restricted-flow packs with warnings.

Claims to take care with

Cosmetic claims include 'purifying', 'clarifying' and 'helps keep skin clean', while 'antiseptic', 'antifungal' or 'treats acne' are therapeutic (TGA). 'Antibacterial' is cosmetic only within the Excluded Goods conditions.