Propylene glycol is technically speaking an alcohol, with a number of functions when used in skin care products. One of these is its ability to attract and hold water (humectant) which can help hydrate the upper skin layers (stratum corneum). This is important for maintaining a healthy skin barrier function.
A study of people diagnosed with mild atopic dermatitis have showed that a lotion with high concentrations of propylene glycol (20%) was similarly effective at reducing itchy and dry skin (scaling, roughness, redness) on the lower legs as a control cream (4% urea)1.
After applying the moisturisers twice daily for two weeks, both treatments had improved the dry skin related symptoms, as reported both by the study participants and by the physicians. But one moisturiser was not better than the other.
The concentration of an ingredient is important for its efficacy, and therefore products containing the same ingredient may not necessarily have the same effect as in the studies mentioned above. Updated: July. 2017
Updated: July 2017