In recent years, new technologies have enabled the production of biofunctional textiles. There textiles are able to release therapeutic compounds or cosmetics to the skin. In this work, after the foulard application of an encapsulated active principle (the sun filter)onto cotton fabrics a new methodology for assessing the in vivo efficacy of the active principle applied to the textile as well as for the in vitro demonstration of its penetration into the skin has been developed. When the biofunctional textile is placed in close contact with the skin for som time, it is possible to evaluate its skin effectiveness using non-invasive biophysical techniques.