Do shake lotions, zinc oil and polyethylene glycol gels produce dehydration or moisturization?

We carried out three studies to evaluate the effects of white zinc shake lotion (Zinkschüttelmixtur DAC), zinc oil ( Zinköl NRF 11.20), Lotio Cordes, PEG ointment (Polyethylenglykolsalbe DAB) and PEG paste on nonmoisturized and moisturized skin. The aim of the study was a clear indication for these vehicles in the clinical practice. Studies 1 and 2 were performed on 20 healthy volunteers. Study 1 was carried out on nonmoisturized skin, while test areas in study 2 were treated with the study products after 1-hour moisturization with hydrophilic aqueous ointment (hydrophile wasserhaltige Salbe DAB), covered with a semiocclusive film dressing. Study 3, carried out on 10 subjects, differed from study 2 by a longer follow-up period. The water content of the horny layer before and after application of the different vehicles was estimated by the capacitance measurement (Corneometer CM 820) and the conductance measurement (Skikon). The glycerol-containing zinc shake lotion and both PEG gels (with or without zinc oxide) produced hydration under the conditions of study 1 and 2. Zinc oil and moisturizer-free Lotio Cordes had little impact on stratum corneum hydration under the conditions of studies 1-3. Therefore, zinc shake lotion and the two PEG ointments can be used in the treatment of dry atopic skin, but not in overhydrated skin, e.g. in intertriginous regions. Zinc oil and Lotio Cordes can be used in overhydrated skin but not in dry skin, for the missing water-binding capacity in the horny layer. On the other hand an effective dehydrating effect cannot be expected.