Dermal Absorption NAMs in Cosmetic Safety Assessment

Dermal absorption NAMs in cosmetic safety assessment are becoming an increasingly important area as safety assessment shifts from hazard-driven to exposure-led science. In this context, understanding skin penetration is critical.

NAMs are supporting this shift through a combination of in vitro and in silico approaches. These methods are generating and extending human-relevant data to support cosmetic safety assessment and non-animal cosmetic safety decisions.

Why Dermal Absorption Matters

Dermal absorption is essential to understanding skin penetration. As cosmetic safety assessment becomes increasingly focused on exposure, skin penetration becomes a critical part of the assessment process.

This is why dermal absorption is emerging as one of the most compelling applications of NAMs. The shift from hazard-driven to exposure-led science increases the importance of approaches that can provide human-relevant data on dermal absorption.

In Vitro and In Silico Dermal Absorption NAMs in Cosmetic Safety Assessment

In vitro NAMs are already contributing to dermal absorption assessment through:

• Reconstructed human epidermis models

• Franz diffusion cells

• Advanced skin barrier systems

These approaches are generating increasingly human-relevant data.

In silico NAMs are extending these insights through:

• QSAR models predicting skin permeability from molecular descriptors

• PBPK and PBK models translating dermal absorption into systemic exposure predictions

• AI-driven permeability prediction trained on experimental datasets

• Mechanistic diffusion models simulating transport across skin layers

These approaches are no longer theoretical. OECD Test Guideline 428 and updated OECD dermal absorption guidance already support the use of in vitro skin absorption methods in regulatory assessment.

At the same time, PBPK-driven NGRA frameworks are increasingly demonstrating how integrated in vitro and in silico NAMs can support non-animal cosmetic safety decisions.

Opportunities and Challenges

The opportunity for dermal absorption NAMs in cosmetic safety assessment is significant. These approaches can support:

• Faster ingredient screening

• Better human relevance

• Reduced animal testing

• More scalable safety assessment

However, several challenges remain:

• Formulation complexity

• Variability in skin barrier function

• Limited high-quality human datasets

• Confidence in model extrapolation

These opportunities and challenges reinforce the importance of an integrated approach. The future of dermal absorption will not rely exclusively on experimental methods or computational models.

An Integrated Future for Dermal Absorption

The future of dermal absorption will not be purely experimental or purely computational. It will be integrated.

Dermal absorption NAMs in cosmetic safety assessment combine experimental and computational approaches, bringing together in vitro NAMs and in silico NAMs. This integration can support human-relevant data, exposure-led science, scalable safety assessment and non-animal cosmetic safety decisions.