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New guideline reduces animal testing and protects from allergies caused by chemicals


ECHA has published advice to registrants on how to reliably combine different sources of alternative data when assessing skin sensitisation of chemicals. This reduces the need to test on animals, while protecting people from allergies. The advice is based on a recent OECD guideline.

Helsinki, 13 October 2021 – The OECD guideline informs REACH registrants on how to reliably combine different sources of non-animal data on skin sensitisation properties of their substances. It will help companies to reduce animal testing while ensuring that people are protected from allergies caused by chemicals.   

ECHA has now published advice on how to use the guideline and advance the use of non-animal test methods. This is the first guideline outlining how to use in silico tools (using computer simulation) such as the QSAR Toolbox to assess skin sensitisation.

Mike Rasenberg, ECHA’s Director for Hazard Assessment says: “This is an important milestone for advancing the use of alternative methods to assess chemical hazards. With the new guideline, we make sure that this approach can be used to protect people against skin sensitisation, without the need to conduct tests on animals. ECHA contributed significantly to its development in close cooperation with the OECD, Joint Research Centre and other organisations.

The guideline contains defined approaches for assessing whether a substance is a skin sensitiser, and categorising whether the sensitisation is strong or moderate. This categorisation is especially important, as REACH requires skin sensitisation potency to be assessed. If the defined approach results in a conclusion on skin sensitisation and potency, it can replace the currently used in vivo method Local Lymph Node Assay, reducing testing on animals.

Using the guideline helps registrants who have already submitted in chemico or in vitro data in their registrations but are uncertain whether this data is accepted by regulators. ECHA encourages those registrants to check whether they can use the defined approaches for their substances to make conclusive predictions and update their dossiers accordingly. If registrants cannot make conclusive predictions, they may need to generate new data or use a weight of evidence approach. The guideline also helps registrants select the most suitable tests to generate new data for substances.


Since 2017, REACH requires registrants to use in vitro methods (tests outside a living organism, usually involving isolated tissues, organs or cells) to provide data on skin sensitisation.

From information in ECHA’s Classification and Labelling Inventory, there are over 14 000 substances on the EU market with some indication of a skin sensitising concern.  Allergic contact dermatitis is a common occupational and environmental health issue. Many skin sensitising chemicals are already restricted under REACH.


The OECD QSAR Toolbox is a free software application that supports reproducible and transparent chemical hazard assessment. It is developed by OECD and ECHA.