The moisturizing effect of vesicles formed from monoglycerides on human skin was studied by measurement of conductance on and transepidermal waterloss from the skin surface. Although sonication of the monoglycerides in water with Ca2+ gave multilamellar vesicles, the lamellar structure of the vesicles disappeared during their storage without any other additive. With the addition of poly(vinylpyrrolidone) after the sonication, the stability of the vesicles increased and their lamellar structure was maintained for 3 months at 40 degrees C. These vesicles led to a significantly higher water content of the stratum corneum of human skin compared with non-lamellar monoglyceride, and consequently they improved rough human skin.