ISO/TR 18811 is a technical report that provides scientific guidance on how cosmetic stability testing should be approached. Rather than establishing mandatory test conditions or acceptance criteria, it offers a framework to help manufacturers design appropriate stability studies based on the characteristics of each product.
Understanding the role of ISO/TR 18811 helps cosmetic brands interpret laboratory reports correctly and develop testing programmes that are both scientifically justified and aligned with European regulatory expectations.
What is ISO/TR 18811?
ISO/TR 18811:2018, Cosmetics — Guidelines on the stability testing of cosmetic products, was published by the International Organization for Standardization (ISO) to provide guidance on stability assessment for cosmetic products.
Importantly, this document is a Technical Report (TR) rather than an International Standard. That distinction matters. Unlike a standard that specifies mandatory requirements or detailed test methods, a technical report provides recommendations, background information and good scientific practices. It helps manufacturers understand how stability testing can be planned but leaves the final testing strategy to the company responsible for placing the product on the market.
Is ISO/TR 18811 mandatory in the European Union?
No. Neither Regulation (EC) No 1223/2009 nor any official European guidance requires manufacturers to comply specifically with ISO/TR 18811.
However, the Regulation requires that cosmetic products are safe under normal or reasonably foreseeable conditions of use. Demonstrating product stability forms part of the scientific evidence supporting that safety assessment.
Because ISO/TR 18811 reflects internationally recognised scientific principles, many laboratories and regulatory professionals use it as a reference when designing stability studies and documenting their rationale.
What does ISO/TR 18811 actually say?
One of the most important messages in ISO/TR 18811 is that there is no universal stability testing protocol suitable for every cosmetic product.
The report recognises the enormous diversity of cosmetic formulations, packaging systems, storage conditions and intended uses. As a result, it concludes that manufacturers should establish and justify their own stability protocols based on scientific reasoning rather than following a single predefined procedure.
This flexible approach is consistent with European cosmetic legislation, which places responsibility on the manufacturer to generate appropriate evidence for each individual product.
ISO/TR 18811 discusses the main elements that should be considered when planning a stability programme. Among the topics addressed are:
- The scientific principles behind cosmetic stability
- Factors that may influence product stability
- Selection of appropriate testing methods
- Storage conditions and study design
- Evaluation of stability results
- Documentation of conclusions
The report also reviews existing scientific references and previously published guidance, providing manufacturers with a useful framework for selecting appropriate testing strategies.
How should manufacturers use ISO/TR 18811?
For most cosmetic companies, ISO/TR 18811 is best viewed as a reference document rather than a compliance checklist.
It helps manufacturers understand why stability testing programmes differ between products and why laboratories may recommend different study designs depending on the formulation being evaluated.
Rather than asking whether a product is “tested according to ISO/TR 18811”, it is usually more appropriate to ask whether the stability programme has been designed using scientifically justified principles that are consistent with its recommendations.
