Another option is to use cultured or reconstructed human skin models; but such systems are not yet recommended for in vitro testing, on the basis of an insufficient barrier function (Bouwstra et al., 2008). Some studies propose the use of a fully differentiated human skin trilayer that could have multiple applications such as in vitro drug absorption tests and regenerative therapies (Monfort et al., 2013); but such engineered skin has not yet been validated.