//8RReconstructed skin and epidermis models are finding increasingly numerous applications in cosmetology and dermatology. In particular, they are currently employed to assess the tolerability and efficacy of raw materials and formulations, in conditions approaching those of normal use. Importantly, the use of such models greatly reduces the need for animal testing. Various models of reconstructed skin and epidermis have been developed [1–4] and some are now produced industrially [5–8]. They are used for the prediction of cutaneous irritancy and, to a lesser extent, percutaneous absorption and cutaneous metabolism. However, before being officially recognized as valid alternative methods and entering routine use, standard protocols must be developed to assess their reproducibility and performance as compared with in situ human studies.