Tea tree oil
Under the IFRA Standards a rinse-off soap may hold up to 3.4 % of this oil, a limit set by its Methyl eugenol.
IFRA maximum for soap
Restricted constituents, at the typical levels IFRA's annex gives:
- Methyl eugenol
- 0.05 %
- beta-Cedrene
- 0.03 %
Worked out from typical levels. A supplier's certificate for your lot comes first, and its figure is the one to follow.
Check a blend against its IFRA limits and list its allergens in the fragrance and allergen calculator.
How essential oils behave in soap, and how much to use: Scenting soap.
Identity and labelling
Melaleuca Alternifolia Leaf Oil
- Botanical name
- Melaleuca alternifolia
- CAS
- 8022-72-8, 68647-73-4
The EU does not name this oil itself as an allergen to label, but some of its constituents may be: the fragrance allergen tool works them out for a recipe.
What it is and how it behaves in soap
Tea tree oil is steam-distilled from the leaves and terminal branchlets of Melaleuca alternifolia (ISO 4730), mostly on Australian plantations (SCCS). It smells sharp, camphor-like and medicinal.
It behaves well in cold process (Faiola) and is a middle note that softens with lavender, lemon or rosemary (Cable; Fisher). Recipes use it at 0.8 to 3 % of the oils (Cable) and 1.4 to 2.1 % (Faiola). The IFRA figure on this page is the ceiling. Books sell tea tree soap as antibacterial or for acne, but no soap is a medicine: what tea tree adds to a bar is its scent.
Oxidised tea tree oil sensitises skin more (SCCP). In 2025 the SCCS found it safe only in shampoo (up to 2 %), shower gel and face wash (1 %) and face cream (0.1 %), bar soap not among them. A draft EU regulation would class it toxic to reproduction, which would bar it from cosmetics sold in the EU unless an exemption is granted; that is not law yet, and Great Britain's regulator has not proposed the same class. Check the rules before selling. It is the oil most often reported in pet poisonings (Merck Veterinary Manual).
Recipes that use it
Sources
- CosIng, the cosmetic ingredient database: MELALEUCA ALTERNIFOLIA LEAF OIL, European Commission. The CosIng entry carries no status; there is no active entry under this name.
- ISO 4730, Essential oil of Melaleuca, terpinen-4-ol type (tea tree oil), 2025 draft text, International Organization for Standardization (2025). Steam distillation of the leaves and terminal branchlets
- Anne-Marie Faiola, Soap Crafting, Storey Publishing (2013). Tea tree among the essential oils that are typically wonderful in cold process soap
- Kelly Cable, The Natural Soap Making Book for Beginners, Althea Press (2017). Tea tree as a middle note that blends with lemon, lavender and rosemary; at 0.8 to 3 % of the oils
- David Fisher, The Complete Photo Guide to Soap Making, Creative Publishing International (2018). Tea tree among the middle notes
- Anne-Marie Faiola, Pure Soapmaking, Storey Publishing (2016). Tea tree at 1.4 to 2.1 % of the oils
- Opinion on tea tree oil (SCCP/1155/08), Scientific Committee on Consumer Products, European Commission (2008). Tea tree oil is a sensitiser, and oxidation products formed with air and heat add to it
- Scientific Opinion on Tea Tree Oil (SCCS/1681/25), Scientific Committee on Consumer Safety, European Commission (2025). Safe only in shampoo, shower gel, face wash and face cream at set maxima, for adults; considered in view of a possible classification as toxic for reproduction (Repr. 1B) recommended by ECHA's Risk Assessment Committee; Australian plantation-grown oil
- Draft Commission Delegated Regulation amending Regulation (EC) No 1272/2008 (24th adaptation to technical progress), notified to the WTO as G/TBT/N/EU/1172, European Commission (2025). Annex: tea tree oil as Repr. 1B (H360Fd), following the Risk Assessment Committee's opinion of 30 November 2023; not yet adopted or published in September 2026
- Agency opinion on the classification of tea tree oil (GB CLP), Health and Safety Executive (2025). Proposes the Risk Assessment Committee's classes except reproductive toxicity and STOT SE 3, which need further assessment
- Kia Benson, Toxicoses From Essential Oils in Animals, Merck Veterinary Manual, Merck & Co. (2025). Tea tree oil the most commonly reported essential oil intoxicant in pets
- Khan, McLean and Slater, Concentrated tea tree oil toxicosis in dogs and cats: 443 cases (2002-2012), Journal of the American Veterinary Medical Association 244, American Veterinary Medical Association (2014)