Skin Irritation (OECD TG 439)

Skin irritation refers to the production of reversible damage to the skin following the application of a test substance. Understanding the potential of topically-applied chemicals or formulations to induce skin irritation (hazard) is an important consideration in their safety evaluation.

The EpiDerm Skin Irritation Test was developed and designed to predict skin irritation potential of neat test substances in the context of identification and classification of skin irritation hazard according to the EU classification system (R 38 or no label) and the UN GHS system. The EpiDerm Skin Irritation Test allows for the discrimination between irritants of category 2 and non-irritants.

MatTek offers the EpiDerm Skin Irritation Test as a GLP or non-GLP service.


Test ModelEpiDerm
ReplicatesN=3 tissues per test condition
Exposure Time1 hour topical exposure to
30µl or 25mg of test material per tissue
Test Article Quantity1ml or 1g
Assay ControlsNegative Control – Sterile DPBS
Positive Control – 5% SDS
EndpointsMTT Tissue Viability Assay
Data Delivery% relative viability ± SD
In vitro classification

Download the EpiDerm Skin Irritation Test Protocol


The determination of skin irritation potential of test materials is based on tissue viability.  According to the EU and GHS classification (R38 / Category 2 or no label), an irritant is predicted if the mean relative tissue viability of triplicate tissues exposed to a test material is reduced below 50% of the mean viability of the negative controls.


in Vitro Resultin Vivo Prediction
Mean tissue viability < 50%Irritant (I), (R38 or GHS Category 2)
Mean tissue viability > 50%Non-irritant (NI)


Download the OECD Test Guideline 439

Reference 809 – Application of MatTek In Vitro Reconstructed Human Skin Models for Safety, Efficacy Screening, and Basic Preclinical Research

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