The assessment of skin penetration is crucial for evaluating occupational and public health risks of industrial chemicals. Skin samples, from humans or animals, are used, with human skin data considered standalone for predicting absorption. A recommended approach involves the "Triple Pack," integrating in vivo and in vitro animal studies with human in vitro dermal absorption studies to enhance reliability. Reconstructed human epidermis models and synthetic membranes are explored, with the latter recommended for initial screening due to simplicity but limited correlation with human absorption data. Biological skin models are suggested for accurate permeation data in hazard assessments.