Skin irritation – OECD 439 (RHE – Reconstructed Human Epidermis)

Skin irritation assessment is a key regulatory requirement in the safety evaluation of cosmetic, chemical, and biocidal products. In accordance with European regulations prohibiting animal testing for cosmetic purposes, in vitro are now preferred.

The OECD 439 test is based on the use of reconstructed human epidermis (RHE) models and allows for the standardized evaluation of the irritant potential of a topically applied substance or formulation.

Objectives of the analysis according to OECD TG 439

• Evaluate irritant potential without using animals , on a relevant human biological model
• Classifying a substance or mixture as "irritant" or "non-irritant" according to GHS criteria (CLP, REACH, EC Cosmetics Regulation No. 1223/2009)
• Meeting national and European regulatory requirements (REACH, BPR, DIP)
• Contribute to the creation of a toxicological safety dossier (PSUR, cosmetic annexes, etc.)

OECD Method Principle 439

The test is based on measuring the cell viability of a reconstructed human epidermis after direct exposure to the tested substance. Residual viability is measured by the MTT assay (ability of living cells to reduce a colored salt).

• A viability < 50% indicates an irritant effect (H315 classification)
• A viability ≥ 50% classifies the product as non-irritating

Test duration : approximately 42 to 60 minutes of exposure, followed by a post-incubation period.

RHE models available

• EpiSkin®
• EpiDerm™
• SkinEthic™ RHE

These models are validated by EURL ECVAM and comply with international standards (OECD, ISO, BPR).

Products concerned

• Cosmetics: facial care, cleansers, sunscreens, pure active ingredients
• Chemicals (REACH, CLP)
• Biocides, pesticides, industrial formulations
• Topical medications, medical devices for cutaneous use

Results provided

• Viability rate (%)
• Regulatory interpretation (irritant/non-irritant)
• Before/after photos of the model
• Full study report (GLP if required)

Why choose YesWeLab?

• YesWeLab connects you with partner laboratories specializing in in vitro GLP- certified platforms , ISO 17025 , and experience in regulatory testing according to OECD 439.
• Our experts will assist you in choosing the protocol, validating samples and writing reports tailored to your regulatory obligations.

See also:

• In vitro skin absorption (OECD 428)
• In vitro eye irritation test (OECD 492)
• Skin corrosion test (OECD 431)