The influence of water, glycerin, paraffin oil and ethanol on skin mechanics.

Moisturizers and emollients do not only smooth the skin but also make it more supple. To clarify this effect, the short-term influence of tap water, paraffin oil, ethanol and glycerin on skin mechanics was studied. These substances are all common ingredients in moisturizers and emollients. Significant changes were seen already after 10 min of application. The distensibility and hysteresis (creep phenomenon) showed the most pronounced changes. Water and paraffin oil application caused significant (p < 0.03) increases after 10 min of application. The changes persisted for at least 10 min following paraffin oil application, while they disappeared sooner following water application. Application of ethanol had a negative effect on distensibility (p < 0.03). Glycerin appears to have a slow onset of action, but with the changes continuing even after application was stopped. The changes induced by glycerin appear to be similar to those induced by water and paraffin oil. The study shows that some of the most common ingredients in moisturizers and emollients are capable of inducing significant changes in the mechanical properties of human skin in vivo even after a 10-min application, suggesting that the outermost layers of the epidermis play an important role in skin mechanics.