Introduction to The Chemistry of Cosmetics
Few people would whip out a chemistry set, uncork the vials, and slap the compounds on their face. Yet, millions of women and girls essentially do that every day when they unzip their makeup bags and apply lipstick, mascara, and other makeup. Like the compounds in a chemistry set, makeup consists of chemicals. Although the chemicals in cosmetic products are intended to improve the appearance of skin, lips, and lashes, some can cause adverse effects.
Brushing up on makeup chemistry isn't hard: If you can read a label, you are halfway there. The U.S. Food and Drug Administration (FDA) requires cosmetics manufacturers to put labels on makeup listing ingredients in descending order of weight. Ingredients that make up less than 1 percent of the makeup item, such as fragrance or colorants, are listed after other ingredients, not in descending order of weight.
The payoff from even a little bit of learning can be big. A savvy makeup user reduces her chances of developing rashes, eye infections, acne, and other health problems linked to cosmetics. She also is less likely to waste money on expensive cosmetics with formulas similar to those of less costly brands.
The first lesson in cosmetic chemistry is that most makeup ingredients are intended to give the product its color and consistency. A few basic classes of ingredients—coloring agents, bases, bulking agents, sunscreens, and additives—are common to many kinds of makeup.
Coloring Agents
Color is probably what first comes to mind when you think of makeup—ruby lips, dusky eyelids, and rosy cheeks. To produce the rainbow of shades on today's makeup racks, chemists derive dyes and pigments from a variety of compounds that may sound more like they belong in a miner's cart than on a beauty queen's brow.
Coal tar, chromium oxide, aluminum powder, manganese, iron oxide, and mica flakes are just a few examples of mineral ingredients used to add color to our faces. Other pigments and dyes, such as beet powder, come from plants. Those derived from animals include carmine, a crimson pigment made from the ground-up, dried bodies of a cacti-eating bug called the cochineal insect.
Coal-tar Colors—suspected Cancer Culprit
By far the most common coloring agents in makeup are the coal tar colors. Coal tar is a sticky, black liquid produced by heating a kind of coal, called bituminous coal, in large ovens from which air is absent. Coal tar colors are formed from ring-shaped carbon- and hydrogen-containing compounds called aromatic hydrocarbons, which are purified from coal tar.
Coal tar colors are the only makeup ingredients the FDA requires to undergo safety testing for every product batch. That is because many of the compounds have been shown to cause cancer when they are injected into the skin of mice.
As a result of lawsuits filed over safety concerns, some coal tar colors are banned, some are approved for external uses only, and some are approved for external and internal uses. Once the compounds pass safety tests, they are given one of two designations. The term FD&C (Food, Drugs & Cosmetics), means that the color is safe for internal and external use. The term D&C or Ext. D&C means the compound is safe only for external use. Safety studies have found internal use of D&C colors can cause cancer in animals and, in at least one instance, have caused blindness in humans. Coloring agents designated D&C or Ext. D&C should never be applied where they can be absorbed, such as near the eyes and on the lips.
Girls and women who spread face foundation on their lips or eyelids before applying lipstick or eye shadow should pay close attention to labeling information. In addition, coal tar dyes occasionally trigger allergic or irritant reactions such as rashes or inflammation, with yellow and red hues posing the most problems.
Bases
Developing alluring colors is not the only challenge facing makeup chemists. Another task is finding ways to make those colors stick to the female face for several hours and through tears, perspiration, drinking, eating, and even kissing. Enter makeup's second major ingredient class: bases.
Almost every type of makeup—from blush to eyeliner—requires some sort of oily or waxy mixture, which makeup manufacturers call a base, to hold the colors together in a cake or tube and help those colors cling to the face. (In this case, base is a manufacturing term, not the chemical term for a substance that can react with an acid to decrease or neutralize acidity.)
Bases In Lipstick and Mascara
The type of base used depends on where the product is supposed to be applied. For example, in lipsticks, about half the weight of the product is accounted for by a thick, insoluble mixture of waxes and castor bean oil that will not dissolve when a woman licks her lips or drinks a beverage. A lipstick base must balance the properties of the oil ingredients with those of wax. The oil in the lipstick makes it viscous (thick and sticky), so that the color clings to the lips. The waxes are thixotropic (becoming fluid only when stirred), so that the lipstick retains its shape and doesn't smear or melt in heat.
Other key ingredients of a lipstick base are slippery chemical compounds called esters, which are formed by reactions between alcohols and acids. Esters are added to make a lipstick shine and make the rather dry oil-and-wax mixture glide onto lips more smoothly.
Like lipstick, mascara relies on relatively heavy bases, such as paraffin and carnauba palm wax, not only to keep lash-darkening pigments stuck to the eyelashes through water and tears, but also to thicken and separate the lashes. On the other hand, eye shadow, blush, and other powdery products are bound together by lighter bases, often mineral oil, because they aren't constantly under assault by makeup-dissolving liquids.
Bases In Face Foundations
Most of the bases used in face foundations are composed of water and mineral oil. Because water and oil do not dissolve in one another, any mixture of the two is an emulsion, in which tiny drops of one liquid are suspended in the second liquid. To help keep them mixed, emulsifying agents such as sodium stearate are added to form a creamy mixture.
Additional ingredients that fall into the base category include isopropyl lanolate, also referred to as wool alcohol; myristyl lactate; and octyl hydroxystearate. These are oillike, nontoxic compounds called fatty esters.
Bases cause relatively few allergic reactions. Lanolin products (which are derived from sheep's wool) or beeswax are the most likely to do so. However, the oils and waxes in makeup can aggravate a medical condition that frequently afflicts teen-agers and young women—acne. The greasy compounds promote the development of whiteheads, blackheads, and pimples because they clog skin pores. Acne-prone women should choose water-based or oil-free cosmetics.
Bulking Agents
A third class of ingredients, bulking agents, play an important role in products requiring even coverage, such as face powder and eye shadow. One of the most common bulking agents is talc or French chalk, a powder made from the mineral magnesium silicate. Talc has long been used in makeup because it absorbs perspiration and has a smooth, slippery texture that makes cosmetics easier to apply.
Women should never inhale deeply when applying products containing talc, such as face powders, eye shadows, and powder blush. Repeated inhalation of talc can cause lung problems, according to medical researchers.
Recently, more-exotic bulking agents have been added to makeup, including silk powder in eye shadow, and nylon and silk fibers in mascara. Dermatologists warn makeup users to be careful when selecting products with those glamorous-sounding ingredients: Silk powder can trigger severe allergic reactions, and fiber-containing mascaras may irritate sensitive eyes.
Sunscreens
Relative newcomers to the ranks of makeup ingredients are sunscreens, which filter out most of the sun's burning rays. In the late 1970's and early 1980's, many makeup manufacturers added sunscreens to their products in response to consumer concerns about skin cancer and other skin-damaging effects of excessive sun.
Compounds that screen out harmful ultraviolet B light include para-aminobenzoic acid (PABA) and its derivatives, as well as benzophenones such as oxybenzone and dioxybenzone. However, both PABA and the benzophenones are common causes of allergic reactions.
Additives
The final class of makeup ingredients, additives, accounts for the lion's share of allergic and irritant reactions. Additives include fragrances and preservatives.
Fragrances are added to makeup to add a pleasing scent and hide the unappealing odor of some waxes, oils, and other makeup components. But the sweet scent comes at a price. A five-year study of 13,216 people conducted by a group of physicians formed by the American Academy of Dermatology found that more than one-third of allergic reactions to cosmetics were triggered by fragrance additives.
Increased public awareness of the allergy-causing potential of fragrance additives, along with a consumer move toward lighter scents, prompted manufacturers to develop alternative products. Products labeled fragrance-free contain no fragrance. Those labeled unscented carry no noticeable scent but still contain enough fragrance additives to mask the smells of other ingredients.
Antimicrobial and Antioxidant Additives
Preservatives that kill microbes are the second major type of additive in makeup. Many bacteria and other microorganisms reproduce rapidly in moist, warm solutions. Without preservatives, mascara, foundation, and other makeup may become an ideal culture medium for harmful microbes.
Manufacturers add a variety of chemicals known to kill microorganisms or stunt their growth. The most common preservatives in makeup are the parabens. The paraben family, which includes butylparaben, ethylparaben, and methylparaben, are rarely allergenic. But preservatives called quarternium-I5, formaldehyde, and sorbic acid are the source of many allergic reactions.
A separate class of chemical preservatives called antioxidants, which are listed on product labels as butylated hydroxyamisole (BHA) and butylated hydroxytoluene (BHT), are added to prevent ingredients from combining with oxygen, a process called oxidation that can ruin makeup's color or texture.
So, what's a girl to do after she's learned about the ingredients that go into her makeup? Why, head for the store! It's there that you can really put your knowledge of makeup chemistry to the test, tailoring your makeup needs to your skin type and budget.
What You're Paying For
First, let's consider price. Do buyers really get what they pay for? According to experts from the FDA and the Cosmetic, Toiletry, and Fragrance Association, the answer lies in what a customer wants. If you demand stylish packaging, the latest rage in colors, and personal assistance, the more expensive products sold in department stores might be a good choice. But if price and performance are your main concerns, experts say you can find many relatively inexpensive makeup products at drug or discount stores with formulas nearly identical to those of more costly brands.
When comparison shopping, remember to check the label to find out how much the product weighs. Products with cheaper price tags often weigh much less than more costly items, even though they appear to be the same size.
Environmentally Sound and Animal-friendly Products
Shoppers with an environmental bent should be aware that when it comes to makeup packaging, the words natural and not tested on animals may not mean all that they imply. Because the FDA puts no limits on what the term “natural” may describe, makeup products described as “natural” are allowed to contain preservatives. Also, dermatologists say that the allergy risk posed by natural makeup may be greater than that from other products, in part because natural plant and animal extracts inherently may contain more impurities than their synthetic counterparts.
Animal testing is another area in which makeup manufacturers often stretch the truth. Just because a makeup item is labeled not tested on animals doesn't mean its ingredients haven't undergone animal testing for products previously put out by the manufacturer or undergone recent animal testing in products made by other manufacturers.
Makeup For Oily, Acne-prone Skin
Finally, women and girls with special makeup needs should get into the habit of closely reading labels, not only for ingredients but for descriptions. Oily, acne-prone skin is the most common makeup challenge facing more than three-quarters of teen-agers and young women. If you have such skin, choose products that are labeled noncomedogenic, meaning they don't promote the formation of whitehead or blackhead pimples, or nonacnegenic, meaning they don't contribute to the formation of any kind of pimple. Select products labeled oil-free, but check the label to see if the product contains other greasy substances such as lanolin, carnauba, petrolatum, or emollient esters.
Although experts agree that acne outbreaks should be treated with medications rather than makeup, some skin foundations try to prevent further flareups with such ingredients as salicylic acid, which fights microbes, and benzoyl peroxide, which acts as a drying agent. Both of these agents are inherently drying to the skin, but a large number of people are allergic to benzoyl peroxide.
Makeup For Dry Skin
Dry skin is often a problem of older women, but it may also trouble younger African-American women. Ingredients to avoid include simple alcohols such as ethanol, methanol, and isopropyl, which dry the skin. It's also a bad idea to use foundations or cover sticks that have added powder, which is a drying agent.
Fatty alcohols, such as cetearyl and stearyl, actually help moisturize dry skin. Other desirable ingredients include lactic acid, glycolic acid, and urea. Although these nonoily compounds, called humectants, do not add moisture to the skin, they cover it with a protective film that prevents water already present in the skin from evaporating.
Makeup and Allergies
Sensitive skin and allergic reactions affect people of all ages, and many makeup products are targeted at this group. Such products are marked hypoallergenic, meaning they are less likely to cause allergies than regular products. Hypoallergenic products usually lack fragrances, preservatives, and other common causes of irritation and allergic reactions. However, women should remember that the products are not 100 percent allergy-proof, and most contain ingredients that trigger some allergic reactions.
The terms allergy tested, sensitivity tested, and dermatologist tested on makeup labels are of little practical importance, because the label doesn't say whether the product passed the test. If you are allergy prone or have sensitive skin, it may be a good idea to test new makeup on your arm for several days before putting it on your face.
Contact-lens wearers should take special care in selecting and using mascara, eye shadow, and other eye makeup. Products to avoid include mascara that contains silk or nylon fibers, as well as water-based mascara that easily flakes and falls into the eye. Frosted eye shadow may be a bad idea because the iridescent particles may fall into your eye and stick to the contact lens, possibly scratching the eye's own lens, the cornea. To reduce the risk of bacterial infection and contaminating particles, wash your hands and put in your contacts before applying eye makeup.
Safety Guidelines For Using Makeup
Whatever type of skin you have or line of makeup you prefer, makeup experts offer three basic safety warnings. First, never apply mascara in a car or other moving vehicle. The most common injury linked to makeup is scratching the eye with a mascara wand. It's not the scratch itself that poses the health hazard, but the sight-threatening infections that can occur if the scratch is not promptly treated.
Second, never use makeup that appears spoiled. If a product has a strange consistency, smells bad, or has changed colors, it may be contaminated with microbes that could cause serious infections. Do not attempt to add water or saliva to makeup that has dried out, because you will add potentially harmful microbes along with that liquid. When not in use, makeup containers should be kept tightly closed and out of sunlight, which can destroy preservatives.
Third, never share makeup. Passing makeup between people also passes microbes back and forth. A similar problem arises with the sharing of testers at cosmetics counters. A 1989 FDA survey found more than 5 percent of counter makeup samples were seriously contaminated with bacteria, mold, and other microbes. Always test lipstick on the back of your hand and ask for a new applicator or cotton swab to test other types of products.
By now, makeup may seem to be the last thing anyone would want to put on her face. Actually, adverse reactions to cosmetics are few and far between. The American Academy of Dermatology estimates there are only about 200 adverse reactions for every million applications.
Those are pretty good odds, but it's never a good idea to gamble with your face. So before you start experimenting with new makeup, take a few minutes to remember your chemistry.