INTRODUCTION
Moisturizers refer to a wide range of consumer products − lotions, creams, serums, and oils designed for the face, body, eyes, hands, and feet. While a primary function is to increase skin hydration, moisturizers deliver other advantages as well, such as improving skin appearance, enhancing skin softness and smoothness, and supplying benefit agents to skin.1 Moisturizers have broad utility within dermatology and can be particularly important as adjuvant therapy for those conditions associated with skin barrier defects, such as atopic dermatitis, to help alleviate symptoms and improve barrier function.2 Research has also indicated that early use of emollients can help reduce the rate of the development of atopic dermatitis.3 For conditions such as acne, where treatments like retinoids and others can worsen barrier dysfunction and increase (TEWL) transepidermal water loss, concurrent moisturizer use can be beneficial.4 Efficacy is a top consideration when selecting a moisturizer for a patient. However, notably, product aesthetics (also known as sensory effects) have become increasingly important to consumers, especially when contemplating the use for body vs face. Consequently, a balance should be struck between efficacy and product aesthetics to encourage daily product use.For decades, moisturizers have been perceived to be formulated in just two ways. Lotions were thinner and known to contain more water; they absorbed faster and were not greasy or unctuous, and thus believed to be less efficacious. Creams, on the other hand, were thicker, oilier, and more dramatically altered the visual appearance of dry skin immediately. As a result, creams were believed to be more moisturizing. However, moisturizer formulation design has become an art as well as a science, and the adage that creams are simply better than lotions because of their consistency is outdated and no longer true. In today’s market, with an explosion of product formats and new scientific techniques for combining ingredients with novel packaging, efficacy, the way a product feels, and what it can deliver to skin can be manipulated in a variety of ways. For example, through the careful selection of emulsifiers, polymers, or thickeners, moisturizer consistency is easily transformed to be thinner or more viscous. With the inclusion of key actives in combination with other moisturizing ingredients, efficacy can be dialed up or down.It should also be noted that price may not be indicative of the degree of effectiveness. Our own internal studies have shown that the clinical efficacy of $100 creams is parity to or even inferior to mass market products containing similar ingredients. Price is most often set by the brand appeal and consumer willingness to pay, rather than the efficacy of the product.This article will discuss the myriad ingredients that are utilized in moisturizers, describe the ways in which formulas can be engineered to create specific, desired outcomes, and debunk some of the long-standing myths that have pervaded the industry. This understanding is crucial for those who are recommending products to consumers or patients.Moisturizers 101: The INCI Differentiating between moisturizers starts with understanding the key components, which can be found on the ingredient label. This label lists the ingredients, by INCI (International Nomenclature Cosmetic Ingredient), in the order of percentage inclusion in the formulation (in most markets). An exception to this rule is that in the US, for ingredients whose inclusion levels are less than 1%, the INCI can be listed in any order irrespective
