Moisture is necessary for healthy skin, but it can be readily depleted by cold winter air and indoor heat. Even daily routines such as cleansing, bathing and towel drying can rob the skin of its natural moisture. The skin also becomes drier as it ages. The cosmetics industry offers a variety of moisturizers aimed at hydrating and softening the skin while assisting with the turnover of skin cells. Certain ingredients play crucial roles in their formulation.
Humectants
Humectants, also called water-binding agents, pull in moisture from the air and help the skin to stay hydrated. Humectants can also help to smooth thickened or scaly skin. Their action is most effective under humid conditions. Glycerin, sorbitol, urea and hyaluronic acid are ingredients often used as humectants in moisturizers.
Emollients
Emollients fill the gaps between skin cells and help to replenish natural oils, thus helping rough, damaged skin become softer and more pliable. Most moisturizers contain at least one emollient. Emollients are typically based on fats or oils, also known as lipids. Palm kernel oil, cocoa butter, lanolin and shea butter are examples of emollients used in moisturizers.
Vitamins
Problems associated with aging skin result not just from the passage of time but from exposure to free radicals generated by sunlight, cigarette smoke, alcohol consumption and environmental pollutants. Antioxidants neutralize free radicals, so certain vitamins with antioxidant properties are sometimes used in moisturizers. According to J. Zussman in the Journal of the American Academy of Dermatology, research studies have demonstrated the value of antioxidant vitamins such as A, C, B-3 and E in repairing and preventing the wrinkles, roughness and dryness of aging skin.
Hydroxy Acids
Hydroxy acids, known also as fruit acids, are a relatively new addition to the list of ingredients found in commercial moisturizers. Hydroxy acids in the low concentrations found in over-the-counter moisturizers serve to slough off dead skin cells, revealing fresher, healthy new skin below. According to a review in Clinics in Dermatology, hydroxy acids also stimulate the production of elastin and collagen, two major building blocks of skin and connective tissue. Liberal use of sunscreen is essential when you use moisturizers containing hydroxy acids because they make your skin more prone to sunburn.
Preservatives
One or more preservatives are typically used in moisturizers, including those featuring otherwise natural or organic ingredients. According to the American Academy of Dermatology, preservatives are among the two leading causes of skin reactions. However, they are a necessary ingredient whose role is to prevent the moisturizer from being contaminated by microbes, molds or bacteria. Parabens, imidazolidinyl urea, Quaternium-15, DMDM hydantoin are examples of preservatives used in moisturizers.
References
- Emedicine: Moisturizers
- "Clinics in Dermatology"; Clinical and cosmeceutical uses of hydroxyacids; B. Green et al; 2009
- American Academy of Dermatology: Cosemeceutical Facts & Your Skin
- "Journal of the American Academy of Dermatology"; Vitamins and Photoaging; J. Zussman et al; March 2010
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