The revised guidance incorporates a testing approach that has already been accepted within OECD Test Guideline (TG) 498, further strengthening the alignment between South Korea’s regulatory framework and internationally recognised methods for non-animal cosmetic safety testing.
Continued progress towards non-animal safety assessment
South Korea has spent several years expanding the use of alternative methods in cosmetic safety evaluation. Legislative changes introduced since 2018 have progressively restricted animal testing for cosmetic finished products and newly developed ingredients, while also limiting the marketing of cosmetics and ingredients that have been tested on animals, except in specific circumstances established by law.
As a result, validated in vitro methods have become an increasingly important part of demonstrating product safety and meeting regulatory expectations.
The latest revision reflects this broader policy direction by expanding the range of recognised methods available to applicants.
KeraSkin™ added to national guidance
The updated document now recognises two reconstructed human epidermis (RhE) models for evaluating phototoxicity:
- EpiDerm™, the validated reference method already included in the guidance.
- KeraSkin™, a Korean-developed reconstructed human skin model that has now been incorporated as an equivalent method under OECD TG 498.
KeraSkin™ was developed and validated by the Korean Center for Validation of Alternative Methods (KoCVAM). Following an independent validation process, it was accepted within OECD TG 498 as a method equivalent to the reference procedure, allowing laboratories to use either approach while maintaining comparable scientific performance.
According to the validation data referenced in the guidance, the method achieved a sensitivity of 100%, specificity of 98.6% and an overall accuracy of 99.3%.
How the test works
Phototoxicity testing is intended to determine whether a substance becomes harmful to skin cells after exposure to ultraviolet or visible light.
The method involves applying the test substance to a reconstructed human epidermis model before exposing part of the tissue to simulated sunlight. Cell viability is then compared between irradiated and non-irradiated samples using the MTT assay, enabling laboratories to identify phototoxic effects under controlled conditions.
The procedure combines established elements from OECD Test Guidelines 439 and 432 while following the requirements set out in OECD TG 498 for reconstructed human epidermis phototoxicity testing.
Scope and limitations
The guidance also clarifies when this type of assessment is appropriate.
Before performing the test, laboratories should evaluate whether the substance absorbs sufficient UV or visible light, following OECD TG 101. Compounds with a molar extinction coefficient below 1,000 L·mol⁻¹·cm⁻¹ are considered unlikely to trigger a photochemical reaction and may not require phototoxicity testing.
The document also notes that the method may not be suitable for certain mixtures or unstable substances. In addition, it is designed specifically to assess phototoxicity and should not be used to predict other light-related hazards, such as photoallergy, photogenotoxicity or photocarcinogenicity.
What this means for cosmetic companies
For cosmetic manufacturers and safety assessors operating in South Korea, the revision expands the recognised toolbox of non-animal testing methods without changing the underlying regulatory objective.
By incorporating KeraSkin™ into the national guidance, South Korea continues to harmonise its safety assessment framework with OECD standards while supporting the wider adoption of validated alternative methods. Companies developing products for the Korean market should ensure that their testing strategies reflect the updated guidance when preparing safety data for regulatory submissions.
