Two Randomized, Controlled, Comparative Studies of the Stratum Corneum Integrity Benefits of Two Cosmetic Niacinamide ⁄ Glycerin Body Moisturizers vs. Conventional Body Moisturizers

January 2012 | Volume 11 | Issue 1 | Original Article | 22 | Copyright © January 2012

Jeremy C. Christman MS,a Deborah K. Fix BS MBA,b Sawanna C. Lucus BS,a Debrah Watson BS,a Emma Desmier BS,a Rolanda J. Johnson Wilkerson PhD,a Charles Fixler MDb

aThe Procter & Gamble Company, Cincinnati, OH bPrivate Practice, Cincinnati, OH

Abstract
Background and Objective: Despite numerous body moisturizers being available, cosmetic xerosis continues to be a leading skin problem for consumers. We performed two 35-day studies to evaluate the ability of a variety of body moisturizers containing various levels of oils/lipids, humectants, as well as other ingredients (e.g., niacinamide) to improve stratum corneum integrity.
Methods: 63 and 58 female subjects were enrolled and randomized in an incomplete block design to six of nine products (eight moisturizers or no treatment control) in studies 1 and 2, respectively. The primary endpoints included visual dryness by a qualified skin grader, skin hydration as measured by Corneometer, and barrier integrity as measured by transepidermal water loss (TEWL). The primary comparisons for the two niacinamide/glycerin moisturizers were to the other six moisturizers and to the no treatment control for each endpoint.
Results: The two niacinamide/glycerin moisturizers demonstrated an overall better solution towards rapid and prolonged improvement of cosmetic xerosis due to functional improvement of stratum corneum barrier function compared to no treatment and the other moisturizers tested.
Conclusions: These studies establish the benefit of including niacinamide in a body moisturizer to improve the integrity of the stratum corneum and thus reduce cosmetic xerosis over time.

J Drugs Dermatol. 2012;11(1):22-29.

INTRODUCTION

Cosmetic xerosis, or “dry skin,” is a condition in which there is a disruption of water gradients within the stratum corneum. A change in the barrier homeostasis of the stratum corneum can occur for a variety of reasons, including low environmental temperature and humidity (e.g., winter), abrupt changes in environmental conditions (e.g., effects of indoor climate-controlled environments), and soap-induced dryness.1 The “dry skin” condition is most commonly treated with topically applied moisturizers. Moisturizer formulations are designed with specific ingredients including oils, emulsifiers, and humectants that influence their aesthetic properties and can affect the function of the stratum corneum. 2 Moreover, some ingredients maintain and improve barrier function, while there are some that are detrimental to barrier function.3-7 Despite numerous body moisturizers being available, cosmetic xerosis continues to be a leading skin problem for consumers. Many technologies provide cosmetic benefits without addressing the underlying causes of xerotic skin. We performed two studies to evaluate the ability of a variety of leave-on body moisturizers containing various levels of oils/lipids (e.g., petrolatum and mineral oil), humectants (e.g., glycerin), as well as other ingredients (e.g., niacinamide) to improve stratum corneum integrity.

MATERIALS & METHODS

Two 35-day, double-blind, randomized, untreated-controlled, clinical studies were performed in Cincinnati, OH from February 10 through March 19, 2009 (average daily temperature: 41.6 °F). Women aged 18 to 65 years with Fitzpatrick skin types I–IV were randomized. Written informed consent for participation in this study was obtained from all subjects in accordance with the Helsinki II declaration.