Moisturizers are used on all skin types to address a range of skin issues/needs—including protection, healing and treatment, as well as moisturization. Main uses include: prevention in normal and dry skin, healing of irritated skin and treatment of diseased skin. Despite their widespread use and applications, however, the scientific literature on moisturizers lacks strong evidence to support dermatological use. Stronger scientific support of moisturizer efficacy will both help dermatologists treat cutaneous disorders and support their decisions with evidence1 as well as help manufacturers improve the efficacy of their products. This article explores current literature on the efficacy of moisturizers to help the industry understand their mechanisms and role in treatment.
Challenges to Clinical Studies
It is difficult to clinically study the efficacy of moisturizers in a meaningful way. The most reliable evidence is from prospective, double-blind, placebo-controlled clinical trials but these are demanding due to challenges such as the lack of harmonized methods, variations in test location on the body and volunteer compliance. Without a standard method to evaluate efficacy, the outcome of improved skin symptoms is time-consuming and difficult to standardize. A visual assessment, which is used frequently, is not sufficient on its own.
In addition, studies in humans do not test the most common location of dry skin—the hands. The forearm is used due to its correlation with skin reactions on the back of the hands to irritants and moisturizers. Although the forearm is thought to be easy to handle, it may not be the ideal body part to study.2 Finally, as noted, volunteer compliance is often a limiting factor. Strong smell, greasy compositions and irritation from the products may make studies unpleasant to complete.