ISO 4730:2025

Essential oil of Melaleuca, terpinen-4-ol type (tea tree oil)

This document specifies certain characteristics of the essential oil of Melaleuca, terpinen-4-ol type (tea tree oil), in order to facilitate assessment of its quality.

Huile essentielle de Melaleuca, type terpinén-4-ol (huile essentielle de Tea Tree)

ISO 4730:2017 spécifie certaines caractéristiques de l'huile essentielle de Melaleuca, type terpinèn-4-ol (huile essentielle de «Tea Tree»), destinées à faciliter l'évaluation de sa qualité.

General Information

• Status: Published
• Publication Date: 11-Jun-2025
• ICS: 71.100.60 - Essential oils
• Technical Committee: ISO/TC 54 - Essential oils
• Drafting Committee: ISO/TC 54 - Essential oils
• Current Stage: 6060 - International Standard published
• Start Date: 12-Jun-2025
• Due Date: 01-Jun-2025
• Completion Date: 12-Jun-2025

Relations

• Revises: ISO 4730:2017/Amd 1:2018 - Essential oil of Melaleuca, terpinen-4-ol type (Tea Tree oil) - Amendment 1: Enantiomeric distribution
• Effective Date: 02-Dec-2023
• Revises: ISO 4730:2017 - Essential oil of Melaleuca, terpinen-4-ol type (Tea Tree oil)
• Effective Date: 02-Dec-2023

Overview

ISO 4730:2025 - Essential oil of Melaleuca, terpinen-4-ol type (tea tree oil) - defines the key characteristics and test methods used to assess the quality and authenticity of tea tree oil. The fourth edition updates the standard that facilitates consistent quality assessment, specification, sampling, labelling and storage of this widely used essential oil.

Key Topics and Requirements

The standard specifies physical, chemical and chromatographic requirements and references relevant test methods:

• Identity & appearance: clear, mobile liquid; colourless to pale yellow; characteristic odour.
• Physical constants:
  • Relative density at 20 °C: 0.885 – 0.906 (ISO 279)
  • Refractive index at 20 °C: 1.475 – 1.482 (ISO 280)
  • Optical rotation: +7° to +12° (ISO 592)
  • Miscibility in ethanol 85%: clear solution with up to 2 volumes ethanol per 1 volume oil (ISO 875)
• Chromatographic profile (gas chromatography, ISO 11024): required component ranges form the oil’s fingerprint. Key components include:
  • Terpinen-4-ol: 35.0 – 48.0%
  • γ‑Terpinene: 14.0 – 28.0%
  • α‑Terpinene: 6.0 – 12.0%
  • α‑Terpineol: 2.0 – 5.0%
  • Other constituents: α‑pinene, limonene, p‑cymene, 1,8‑cineole (trace allowed to 10%), etc.
• Enantiomeric distribution (new in 2025 edition, informative):
  • Terpinen‑4‑ol: (R)(+) 67–71% / (S)(–) 29–33%
  • α‑Terpineol: (R)(+) 69–79% / (S)(–) 21–31% (ISO 22972 referenced)
• Flash point (informative): mean closed‑cup value 59 °C (see ISO/TR 11018).
• Sampling & packaging: sampling per ISO 212 (minimum test sample 50 mL); packaging, labelling and storage per ISO 210 and ISO 211.

Applications and Who Uses ISO 4730:2025

ISO 4730:2025 is used by:

• Producers and distillers of Melaleuca essential oil to certify product quality.
• Analytical and QC laboratories to perform gas chromatographic profiling and physical tests.
• Cosmetic, pharmaceutical and aromatherapy manufacturers to specify ingredient acceptance criteria.
• Importers, traders and procurement teams for contract specifications and batch verification.
• Regulatory bodies, transport and insurance companies for safety data (flash point) and compliance.
• Researchers and authenticity specialists using enantiomeric ratios to detect adulteration.

This standard supports traceable quality control, fraud detection and harmonized trade of tea tree oil.

Related Standards

Relevant references include ISO 11024 (GC profiles), ISO 212 (sampling), ISO 279/280/592/875 (physical tests), ISO 210/211 (packaging/label/marking), ISO/TS 24106 (component names), ISO 22972 (chiral GC), and ISO/TR 11018 (flash point guidance).

Standards Content (Sample)

International
Standard
ISO 4730
Fourth edition
Essential oil of Melaleuca, terpinen-
2025-06
4-ol type (tea tree oil)
Huile essentielle de Melaleuca, type terpinén-4-ol (huile
essentielle de Tea Tree)
Reference number
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Requirements . 1
4.1 General .1
4.2 Chromatographic profile .2
5 Additional information . 2
5.1 Flash point .2
5.2 Enantiomeric distribution .3
6 Sampling . 3
7 Packaging, labelling, marking and storage . 3
Annex A (informative) Typical chromatograms of the analysis by gas chromatography of the
essential oil of Melaleuca, terpinen-4-ol type (tea tree oil) . 4
Annex B (informative) Flash point. 7
Annex C (informative) Enantiomeric distribution — General information . 8
Bibliography . 9

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
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related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 54, Essential oils.
This fourth edition cancels and replaces the third edition (ISO 4730:2017), which has been technically
revised. It also incorporates the Amendment ISO 4730:2017/Amd 1:2018.
The main changes are as follows:
— inclusion of enantiomeric distribution parameters for α-terpineol.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
International Standard ISO 4730:2025(en)
Essential oil of Melaleuca, terpinen-4-ol type (tea tree oil)
1 Scope
This document specifies certain characteristics of the essential oil of Melaleuca, terpinen-4-ol type (tea tree
oil), in order to facilitate assessment of its quality.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 210, Essential oils — General requirements and guidelines for packaging, conditioning and storage
ISO 211, Essential oils — General requirements for labelling and marking of containers
ISO 212, Essential oils — Sampling
ISO 279, Essential oils — Determination of relative density at 20 °C — Reference method
ISO 280, Essential oils — Determination of refractive index
ISO 592, Essential oils — Determination of optical rotation
ISO 875, Essential oils — Evaluation of miscibility in ethanol
ISO 11024 (all parts), Essential oils — General guidance on chromatographic profiles
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
essential oil of Melaleuca, terpinen-4-ol type
tea tree oil
essential oil obtained by steam distillation of the leaves and terminal branchlets of Melaleuca alternifolia
(Maiden and Betche) Cheel or of M. linariifolia Sm
Note 1 to entry: For information on the characterization of this essential oil, see ISO/TR 21092.
4 Requirements
4.1 General
Essential oil of Melaleuca, terpinen-4-ol type (tea tree oil)
...