More Than Skin Deep
by C. Leigh Broadhurst, Ph.D.
Understanding the ingredients in personal care products
Skin is a remarkable organ – the body's largest – but it's often taken for granted. Most people are content to ignore it until dryness, oiliness, a rash or a wrinkle rouses attention. But once you understand how it really functions, you may want to reconsider the importance of your skin and the quality and content of the skin care products you use. Consider this:
- An adult's skin comprises between 15 and 20 percent of total body weight.
- Each square centimeter of skin has 6 million cells, 5,000 sensory points, 100 sweat glands and 15 sebaceous glands.1
Your skin is tireless, working constantly to regenerate itself. A cell is born in the lower layer of the skin, called the dermis, then migrates upward for about two weeks until it reaches the epidermis, the bottom portion of the outermost layer of the skin.
The cell spends another two weeks in the epidermis, gradually flattening out and continuing to move toward the surface. Then it dies and is shed. In fact, 2-3 billion skin cells are shed daily. The body expends this effort to replace skin every month because the skin constitutes the first line of defense against dehydration, infection, injuries and temperature extremes.
Skin cells can also detoxify harmful substances with many of the same enzymatic processes the liver uses.2 Furthermore, the unbroken surface prevents infectious organisms from penetrating into the systemic circulation. As gatekeeper, the skin absorbs and uses nutrients applied topically.3 Because it can't completely discriminate, the skin may absorb the synthetic chemicals often present in soaps and lotions, which at best it has no use for and at worst can be irritating or even toxic.3
While many of us are committed to natural foods and remedies, we may not be as selective when it comes to personal care products. Here's a primer to help you understand the often-confusing ingredient lists so that you can determine for yourself the benefits of going natural.
U.S. Food and Drug Administration regulations specify that ingredients on cosmetic product labels be listed in descending order of percent by weight. To help you decode these ingredient names, the following list highlights the most common, tells whether they are natural and provides scientific support for choosing natural over synthetic. The ingredients chart (page 30) provides examples of both common synthetic cosmetic ingredients and natural alternatives.
It's important to note that water is the major component of virtually all skin and hair care products. It's a natural and necessary ingredient, but no matter how you pour it, most of what's being sold is H20. While water always tops the list, water-based herbal extracts may be a better choice than mere distilled water.
After water, fats – which act as emollients and humectants – are the secondary ingredients in moisturizers. An emollient makes skin soft and supple, and a humectant promotes moisture retention. Fats comprise a large part of the skin's structure.
Consequently, providing the correct natural fats is probably the most important aspect of skin care: As well as being part of the skin, fats can augment the body's sebum, providing lasting lubrication and softening. Sebum is secreted by sebaceous glands and consists of a blend of fats, waxes and protein. It protects skin from moisture loss and irritation and is strongly antimicrobial.3 Sebum also makes hair shiny and soft. Abnormal sebum composition or inadequate sebum production causes dry skin that can create itching and flaking. Chronically abnormal sebum production increases the incidence of skin infections and can cause skin cracking, bleeding or scaly dermatitis.
Natural oils (almond, olive, safflower and sunflower) and waxes (beeswax, jojoba and lanolin) work primarily as emollients because they are soluble in the sebum and are capable of being absorbed and used by skin cells.4 In particular, the skin needs omega-6 polyunsaturated fatty acids (PUFAs) because they are not manufactured in the body. Ideally, these should be supplied from the diet (by eating nuts, seeds or vegetable oils, such as flax, hemp, soybean and sunflower) and from lotions that contain almond, safflower and sesame oils. A dietary deficiency of omega-6 PUFA (or of all PUFAs) causes scaly dermatitis, skin lesions and excessive water loss through the skin.5
Humectants are designed to slow water evaporation from skin. Mineral oils are often called emollients, but they really act as humectants. While mineral oil can soften healthy skin in the short term, simply keeping water from evaporating cannot help or heal chronically dry or damaged skin. Mineral oil-based products, which are not considered natural, do not penetrate the skin's surface to provide the raw materials for sebum.6
Removing the day's dirt or makeup requires a cleanser – choosing an appropriate one depends on what's in it.
Liquid soaps and shampoos contain soaps, detergents and surfactants (short for surface active agent). Soap is a sodium salt of medium- or long-chain fatty acids. Detergents are chemically different from soaps but resemble them in the ability to emulsify oils and hold dirt in suspension. Common detergents in skin and hair care products are sodium lauryl sulfate and cocamide DEA, which are also used in dish detergents.1 Product labels may indicate that cocamide DEA is from coconut oil, but it is a synthetic ingredient that may or may not use coconut oil in its manufacture. Remember that DEA, short for diethanolamine, may contain carcinogenic nitrosamines.
Surfactants help wet hair and skin more easily and pick up and remove various soils. All soaps are surfactants, but there are many specialized surfactants available for particular applications.
Foaming agents are often added to shampoos and liquid soaps to increase apparent cleansing and improve rinsing actions. Sequestering agents, which bind metal ions such as magnesium, calcium and iron from hard water, and nonmetal ions such as chlorine, are typically added to shampoos for swimmers and those with color-treated hair. Sequestering agents, either natural (corn syrup) or synthetic (ethylene diamine tetra acetic, abbreviated EDTA), clean the skin and hair more thoroughly and minimize soap scum.
Alcohol is the secondary ingredient in astringent facial cleansers as well as toners. The abbreviation "SD" stands for specially denatured and means a small amount of methanol has been added to the ethanol, making it poisonous. Natural astringents are witch hazel extract and ethanol. Deciding between a natural, beneficial herbal extract and a potentially toxic ingredient is easy once you understand you have a choice.
Chances are you'll see the following ingredients in most personal care products.
Emulsifiers and solubilizers in personal care products keep the ingredients combined and constitute the minor ingredients listed on the label. Emulsifiers keep fats dispersed in water-based mediums – oil in skin lotions or hair conditioners, for example. Solubilizers keep ingredients dissolved. There are few effective natural emulsifiers and solubilizers, which makes avoiding synthetics one of the largest hurdles for natural cosmetic products manufacturers.7 Only the staunchest advocate of natural ingredients is critical of a manufacturer for the use of a synthetic emulsifier and solubilizer in an otherwise natural formula.
Value-added ingredients typically appear next and include amino acids, essential oils, herbal extracts, hydrolyzed protein, protein extracts and vitamins. In general, these constituents are beneficial to the skin and hair, but mainstream products typically contain only token amounts.
Antifungal, antibacterial and preservative agents constitute many of the ingredients. Most personal care products need protection from bacterial and fungal growth as well as from oxidation and other damaging chemical reactions because the bottles are opened regularly. Synthetic antimicrobials and antioxidants are somewhat toxic by nature and are the most likely ingredients to cause irritation and allergic reactions.8
Natural or vitamin-derived antioxidants are rarely irritating7 and in higher concentrations can play dual roles. Topical vitamin C (ascorbic acid) penetrates the skin but is generally not stable in cosmetics. The fat-soluble forms of vitamin E – alpha-tocopherol, alpha-tocotrienol and gamma-tocotrienol – penetrate the skin rapidly and migrate to the dermal areas that contain the sebaceous glands.9
Scientific analysis has always concluded that natural skin care products are inherently safer and more effective than synthetic alternatives.2,10 However, this message isn't being effectively communicated to consumers – the people who really need to know. Don't take your skin for granted.
1. Fiedler HP, Umbach W. Cosmetics and toiletries. In: Falbe J, editor. Surfactants in consumer products: theory, technology and application. Heidelberg (Germany): Springer-Verlag; 1987. p 352-98.
2. Kligman AM, Ligman LH. A hairless mouse model for assessing the chronic toxicity of topically applied chemicals. Food Chem Toxicol 1998;36:867-78.
3. Diembeck W, et al. Test guidelines for in vitro assessment of dermal absorption and percutaneous penetration of cosmetic ingredients. Food Chem Toxicol 1999;37:191-205.
4. Ziboh V. The significance of polyunsaturated fatty acids in cutaneous biology. Lipids 1996;31(Suppl):249-53.
5. Ziboh V, Chapkin R. Metabolism and function of skin lipids. Prog Lipid Res 1988;27:81-105.
6. Shukla VKS, Kragballe K. Exotic butters as cosmetic lipids. INFORM 1998;9:512-6.
7. Krawczyk T. Lipids in cosmetics. INFORM 1997;8:332-7.
8. Hampton A. Natural organic hair and skin care. Tampa (FL): Organica Press; 1987.
9. Traber MG, et al. Penetration and distribution of alpha-tocopherol, alpha- or gamma-tocotrienols applied individually onto murine skin. Lipids 1998;33:87-91.
10. Brehler R, et al. Recent developments in the treatment of atopic eczema. J Am Acad Derm 1997;36:983-94.
C. Leigh Broadhurst, Ph.D., heads 22nd Century Nutrition, a nutrition/scientific consulting firm.