International Academy of Cosmetic Dermatology
Dry skin is common in individuals with and without healthy skin. It can be connected to inherited disorder, such as ichthyosis or atopic dermatitis, or secondarily to other diseases such as diabetes. In healthy skin, the condition can occur in response to exposure to an environment with low humidity and/or low temperature or habitual cleansing of skin with harsh cleansing products.
If adequate water levels in the skin are not maintained, the skin becomes less flexible and appears flaky. It is unclear precisely how much water content should be in skin, as the water content of keratinocytes will vary in the basal layer, stratum granulosum, and lower layers of the stratum corneum. In addition, the outermost layers of the stratum corneum are in equilibrium with the variable ambient relative humidity.
A moisturizer is a product designed to restore and maintain optimum hydration of the stratum corneum. This may be accomplished by increasing water-holding capacity of the stratum corneum via external application of hydroscopic ingredients (humectants) or to trap water in the stratum corneum by depositing am impermeable layer of water-insoluble oily material on the skin surface. Oils and lipids, which render skin soft, supple, and flexible, are frequently referred to as emollients-a word synonymous with moisturizer.
Approaches to moisturizing skin are limited, yet numerous moisturizers are available in the marketplace. In an effort to attract the consumer to a specific product, the cosmetic chemist must consider esthetic product attributes, consumer perception of product performance, and skin care preferences of consumers segmented by age, gender, and to a limited extent, cultural preferences.
The skin care and moisturizer market is divided between face care and hand and body care products. In the 1970’s, facial moisturizers with anti-aging claims became popular. By the 1990’s, products with ingredients, such as alpha hydroxy acid (AHA) became desirable, as consumers noticed visible improvement in the appearance of the skin. Currently, consumers prefer multi-functional moisturizers, such as products that claim to even skin tone or to diminish the appearance of cellulite. More recently, hand and body moisturizers have sought to address the signs of aging, such as photo-damaged hands and arms, age spots, and coarse/textured skin.
The appearance and feel of skin are central to human interpersonal perception and attraction. Skin moisturizing products are a major growth area of the skin care business, as consumers believe young-looking skin feels soft, appearing hydrated and free of fine lines and wrinkles.
Skin plays an important role in the maintenance of physical and mental health. The care of skin has always been a priority in many cultures throughout history. An optimally formulated moisturizer may be considered an essential tool in the quest for personal self-esteem and maintenance of the best possible appearance of one’s skin.
Howard Epstein, PhD
Gibbstown, NJ, USA