When full-thickness pig ear skin was exposed to UVA in the absence of sunscreen, no significant increase in TBARS was observed, and this is the main trend detected even in the other skin samples studied (Fig. 3 and Fig. 4). This does not imply that skin is not damaged by UVA exposure, but rather, that the assay used might not be sufficiently sensitive to detect small amounts of breakdown products of skin lipid peroxidation. In Fig. 4, however, a significant increase in human SCE membranes was noted, differently from the results on the human SCE membranes reported in Fig. 3. As mentioned earlier, the human SCE samples were from two different individuals, hence it is likely that they respond differently when exposed to UVA. Worthy of mention is also the fact that the basal TBARS levels in full-thickness pig ear skin are higher than those detected from human and pig SCE membranes. This is expected since full thickness skin consists of stratum corneum, viable epidermis and dermis, thus basal lipid levels are expected to be higher, compared to SCE membranes which comprise the epidermis and the stratum corneum (Huong et al., 2009).