C

C12-15 alkyl benzoate. Used as an emollient and thickening agent in cosmetics. See glyceryl ester.

C12-18 acid triglyceride. Used as an emollient and thickening agent in cosmetics. See glyceryl ester.

C18-36 acid triglyceride. Used as an emollient and thickening agent in cosmetics. See glyceryl ester.

C20-40 pareth-40. Mixture of polyethylene glycols of various molecular weight that can function as stabilizing agents, solubolizers, and surfactants.

caffeic acid. Potent antioxidant that may have some anticarcinogenic properties (Sources: Toxicology, January 2006, pages 213-220; and Bioorganic & Medicinal Chemistry Letters, June 2002, pages 1567–1570.).

caffeine. Alkaloid found in coffee, tea, and kola nuts. It’s often included in skin-care products with claims that it will reduce cellulite or puffy eyes. Given the prevalence of Starbucks stores all over the world, it would be great news for women’s thighs and eyes if that were the case, but, unfortunately, that is far from the case.

Caffeine’s popularity in products related to cellulite is due to its distant relationship to aminophylline (a pharmaceutical once thought to reduce cellulite), which is a modified form of theophylline (Source: Yale New Haven Health Library, Alternative/Complementary Medicine, www.yalenewhavenhealth.org), and caffeine contains theophylline (Source: Progress in Neurobiology, December 2002, pages 377–392). There is no substantiated research proving theophylline can affect cellulite, but researchers have disproved aminophyilline’s claimed impact on cellulite. The second reason caffeine may show up in cellulite products stems from research showing it to have benefit for weight loss, but that’s only when you drink it, not when you rub it on your thighs.

There are only two studies showing caffeine to have benefit for reducing cellulite. One was conducted by Johnson & Johnson, which owns the RoC and Neutrogena brands, both of which sell cellulite creams that contain caffeine. The other was conducted by cosmetics ingredients manufacturers that sell anti-cellulite compounds (Source: Journal of Cosmetic Science, July–August 2002, pages 209–218). There is no independent research showing that caffeine can provide any benefit for treating cellulite.

When it comes to puffy eyes, there is no research indicating caffeine can have this benefit when applied topically. However, caffeine does have potential as an antioxidant, so it isn’t a wasted ingredient in skin-care products (Sources: BMC Complementary and Alternative Medicine, March 2006, http://www.biomedcentral.com/1472-6882/6/9; Bioscience, Biotechnology, and Biochemistry, November, 2005, pages 2219–2223; Obesity Research, July 2005, pages 1195–1204; and Sports Medicine, November 2001, pages 785–807).

Definition

Caffeine is a substance that exists naturally in certain plants. It can also be produced synthetically and used as an additive in food products. It is a central nervous system stimulant and a diuretic.

Function

Caffeine is absorbed and distributed very quickly. After absorption, it passes into the brain.

Caffeine does not accumulate in the bloodstream nor is it stored in the body. It is excreted in the urine many hours after it has been consumed.

Caffeine will not reduce the effects of alcohol, although many people still believe a cup of coffee will "sober-up" an intoxicated person.

Caffeine may be used as a treatment for migraine headaches and in relieving, for a short time, fatigue or drowsiness.

Food Sources

Caffeine is widely consumed. It is found naturally in the leaves, seeds, and fruits of more than 60 plants, including tea leaves, kola nuts, coffee, and cocoa beans. It is in coffee, tea, chocolate, cocoa and some colas.

Caffeine is frequently added to over-the-counter medications such as pain relievers, appetite suppressants, and cold medicines. Caffeine has no flavor and can be removed from a food by a chemical process called decaffeination.

Side Effects

Excessive caffeine intake can lead to a fast heart rate, excessive urination, nausea, vomiting, restlessness, anxiety, depression, tremors, and difficulty sleeping.

The effect of caffeine on health has been widely studied. In particular, the effects of caffeine on fibrocystic breast disease, heart and blood vessel disease, birth defects, reproductive function, and behavior in children has been closely examined. However, 1984 statement from the American Medical Association Council on Scientific Affairs stated, "Moderate tea or coffee drinkers probably have no concern for their health relative to their caffeine consumption provided other lifestyle habits (diet, alcohol consumption) are moderate as well." This statement emphasizes moderate caffeine use.

Abrupt withdrawal of caffeine may cause headaches, drowsiness, irritability, nausea, vomiting, and other symptoms. Reduce caffeine intake gradually to prevent any symptoms of withdrawal.

Recommendations

There is no human requirement for caffeine in the diet. Moderate caffeine intake, however, is not associated with any health risk. Three 8 oz. cups of coffee (about 250 milligrams of caffeine) per day is considered an average or moderate amount of caffeine. Ten 8 oz. cups of coffee per day is considered excessive intake of caffeine.

A child's caffeine consumption should be closely monitored. Although caffeine is safe to consume in moderation, it may negatively affect a child's nutrition. Caffeinated beverages may be replacing nutrient-dense foods such as milk. A child may also eat less because caffeine acts as an appetite suppressant. Caffeine can be completely restricted in a child's diet since there is no nutritional requirement for it. This may be necessary for a hyperactive child as caffeine is a stimulant.

Pregnant women, and people with coronary heart disease or peptic ulcers may be advised by their health care provider to restrict or avoid using caffeine.

Many drugs will interact with caffeine. Consult with your health care provider or pharmacist about potential interactions with caffeine whenever you take medications.

cajeputi oil. See Melaleuca cajeputi oil.

calamine. Preparation of zinc carbonate, colored with ferric oxide (a form of rust). Zinc carbonate is a counter-irritant used to reduce itching. It is still an irritant when applied to skin so it should be used only as needed. See counter-irritant.

calcium ascorbate. Form of vitamin C; other forms include ascorbic acid, L-ascorbic acid, ascorbyl palmitate, and magnesium ascorbyl phosphate. Calcium ascorbate, often referred to as Ester-C, is considered a stable form of vitamin C and an antioxidant (Sources: Medical Science Monitor, October 2007, pages 205–210; and Journal of Cosmetic Science, November–December 2006, pages 465–473). See Ester-C.

calcium carbonate. Chalk; used as an absorbent in cosmetics.

calcium d-pantetheine-s-sulfonate. See calcium pantetheine sulfonate.

calcium gluconate. Calcium is an essential mineral for the body. A small amount of research shows calcium gluconate may be a good anti-inflammatory and healing agent when applied topically (Source: Annals of Emergency Medicine, July 1994, pages 9–13).

calcium pantetheine sulfonate. There is a small amount of in vitro research showing that this may have melanin-inhibiting properties (Source: Pigment Cell Research, June 2000, pages 165–171).

calcium pantothenate. Also known as pantothenic acid. See pantothenic acid.

calendula extract. Extract derived from the plant commonly known as pot marigold, there is little research showing that it has any effect on skin, though it may have antibacterial, anti-inflammatory, and antioxidant properties. Note: If you have ragweed (or similar plant) allergies, topical application of calendula is not recommended because of the risk of an eczematous allergic reaction (Source: www.naturaldatabase.com).

Calophyllum inophyllum seed oil. See tamanu oil.

Camellia japonica. The leaf has been shown in vitro to be potent antioxidant and also able to inhibit the expression of collagen-depleting MMP-1 when applied to human fibroblast cells (Source: Journal of Cosmetic Science, January/February 2007, pages 19-32). See matrix metalloproteinases.

Camellia oleifera. See green tea.

Camellia sinensis. See green tea.

camphor. Aromatic substance obtained from the wood of a tree common to Southeast Asia, Cinnamomum camphora, or manufactured synthetically. When applied to the skin camphor produces a cooling effect and dilates blood vessels, which can cause skin irritation and dermatitis with repeated use (Sources: British Journal of Dermatology, November 2000, pages 923–929; and Clinical Toxicology, December 1981, pages 1485–1498). See counter-irritant.

cananga extract. Fragrance used in cosmetics; it can be a skin irritant, much like ylang ylang.

Cananga odorata. See ylang ylang.

candelilla wax. Extract derived from candelilla plants; used as a thickening agent and emollient to give products such as lipsticks or stick foundations their form.

Cannabis sativa L. oil. See hemp seed oil.

canola oil. Plant lipid that has barrier-repair and anti-inflammatory properties (Source: British Journal of Dermatology, February 1996, pages 215–220). See natural moisturizing factor (NMF).

caprylic/capric triglyceride. Extract derived from coconut and considered a good emollient and thickening agent in cosmetics.

caprylyl glycol. Skin-conditioning agent that may be plant-derived or synthetic. Often used as part of a preservative blend with phenoxyethanol and chloroxylenol, two preservatives that meet current global regulations.

capsaicin. Component of capsicum. When used topically, capsaicin can prevent the transmission of pain. It is also a potent topical irritant and can trigger dermatitis. See capsicum.

capsicum. Large group of plants consisting primarily of the pepper family, including chili peppers and paprika. These are used as counter-irritants to relieve muscle aches. Capsicum and substances derived from it can cause allergic reactions or skin irritation and should never be applied to abraded skin (Source: www.naturaldatabase.com). See counter-irritant.

capsicum oleoresin. Fatty resin derived from capsicum plants. It can be a skin irritant and should not be applied to abraded skin. See capsicum.

caramel. Natural coloring agent.

carbomer. Group of thickening agents used primarily to create gel-like formulations.

carbopol. See carbomer.

carboxylic acid. See L-carnitine.

cardamom. Plant of the ginger family, used as fragrance in cosmetics. Terpene, one of its major constituents, can be a skin irritant and sensitizer.

carmine. Natural red color that comes from the dried female cochineal beetle. It is sometimes used to color lip gloss, lipsticks, and other cosmetics. The FDA approved carmine for food use in 1977.

carnauba wax. Natural, hard wax obtained from the leaves of palm trees. Used primarily as a thickening agent, but also has film-forming and absorbent properties.

carnitine. Naturally occurring amino acid. Deficiencies of this small but essential component can result in muscle loss and a multitude of other problems. Research abounds for carnitine, especially acetyl-L-carnitine, which is considered to have more bioavailability in terms of its effect on aging and brain function. Research into how this amino acid affects skin when applied topically is limited, though a few studies indicate it can be an antioxidant (Sources: Medical Science Monitor, June 2005, pages 176–180; and International Journal of Biochemistry and Cell Biology, February 2003, pages 149–156).

carnosic acid. Component of rosemary that is a potent antioxidant (Sources: Free Radical Biology and Medicine, June 2002, pages 1293–1303; and Journal of Agricultural Food Chemistry, March 2002, pages 1845–1851).

carnosine. Composed of amino acids, it has anti-inflammatory and antioxidant properties. There is some research showing it has antiglycation properties (Source: Life Sciences, March 2002, pages 1789–1799).

carnosol acid. See carnosic acid.

carrageenan. Seaweed gum used in cosmetics as a thickening agent with water-binding properties.

carrot oil. Emollient plant oil similar to other nonfragrant plant oils. See natural moisturizing factor (NMF).

Carthamus tinctorius oil. See safflower oil.

carvone. Essential oil used as a flavoring agent and fragrance component in cosmetics. It can be a significant skin sensitizer or allergen (Sources: Planta Medica, August 2001, pages 564–566; and Contact Dermatitis, June 2001, pages 347–356).

Carya illinoensis oil. See pecan oil.

casein. Substance derived from milk protein that may have some antioxidant properties when applied topically, although the research for this is limited (Source: International Journal of Food Science and Nutrition, July 1999, pages 291–296).

Castanea sativa seed extract. See chestnut seed extract.

castor oil. Vegetable oil derived from the castor bean. It is used in cosmetics as an emollient, though its unique property is that when dry it forms a solid film that can have water-binding properties. It is rarely associated with skin irritation or allergic reactions, but can have a slightly sticky feel on skin.

catalase. Enzyme that decomposes hydrogen peroxide into water and oxygen and that has significant antioxidant properties (Source: Journal of Investigative Dermatology, April 2002, pages 618–625).

Caulerpa taxifolia extract. See algae.

cedarwood. Fragrant plant extract. There is evidence that cedarwood oil is allergenic and can cause skin irritation. There is also a small amount of research showing it produces tumors on mouse skin (Source: www.naturaldatabase.com).

Cedrus atlantica bark extract. Fragrant oil that can be a skin irritant.

celandine. Extract from the plant Chelidonium majus that has some research showing it has antiviral properties. There is no research showing it has benefit when applied topically.

cell-communicating ingredients. Cell-communicating ingredients, theoretically, have the ability to tell a skin cell to look, act, and behave better, more like a normal healthy skin cell would, or to stop other substances from telling the cell to behave badly or abnormally. They do this by either direct communication with the skin cell or by blocking damaging cellular pathways or other cell-communicating substances. Cell-communicating ingredients complement antioxidants to improve skin-cell function.

Examples of cell-communicating ingredients include niacinamide, adenosine triphosphate, vitamin A (retinol), tretinoin (all-trans-retinoic acid—the active ingredient in prescription products such as Renova and Retin-A), and possibly peptides. Assorted plant extracts and growth factors may play a role in blocking damaging cell communication or enhancing healthy cell communication.

(Sources: Journal of Biological Chemistry, August 2007, pages 22964, 22976; Seminars in Immunopathology, April 2007, pages 15–26; Journal of Investigative Dermatology, December 2006, pages 2697–2706; Microscopy Research and Technique, January 2003, pages 107–114; Nature Medicine, February 2003, pages 225–229; Journal of Investigative Dermatology, March 2002, pages 402–408; International Journal of Biochemistry and Cell Biology, July 2004, pages 1141–1146; Experimental Cell Research, March 2002, pages 130–137; Skin Pharmacology and Applied Skin Physiology, September–October 2002, pages 316–320; and www.signaling-gateway.org). See antioxidant and peptide.

cellulose. Primary fiber component of plants. Used in cosmetics as a thickening agent and to bind other ingredients together.

Centaurea cyanus. See cornflower.

Centella asiatica. Extract of herb that may be listed on labels as asiatic acid, hydrocotyl, or gotu kola. It has antibacterial, anti-psoriatic, and wound-healing properties (Sources: International Journal of Lower Extremity Wounds, September 2006, pages 137–143; Aesthetic Plastic Surgery, May–June 2000, pages 227–234; Phytomedicine, May 2001, pages 230–235; and Contact Dermatitis, October 1993, pages 175–179).

cephalin. Phospholipid. See fatty acid and natural moisturizing factor (NMF).

cera alba. Beeswax; used as a thickening agent in cosmetics.

cera microcristallina. See petrolatum.

Ceramide 1. See ceramides.

Ceramide 3. See ceramides.

Ceramide 6-II. See ceramides.

ceramides. Naturally occurring skin lipids (fats) that are major structural components of the skin’s outer structure. Skin as a barrier system inhibits water movement via its extracellular matrix, which has a unique composition of 50% ceramides, 25% cholesterol, and 15% free fatty acids (Sources: Journal of Lipid Research, September 2007; Journal of Investigative Dermatology, November 2001, pages 1126–1136; and Experimental Dermatology, October 2005, pages 719–726). Ceramides are necessary for the skin’s water-retention capacity as well as for cell regulation. Adding ceramides to skin-care products can help to restore the skin’s barrier system (Sources: American Journal of Clinical Dermatology, June 2005, pages 215–223; Journal of Dermatological Science, September 2006, pages 159–169; Skin Pharmacology and Applied Skin Physiology, September–October 2001, pages 261–271; and Cutis, December 2005, Supplemental, pages 7–12).

ceresin. Derived from clay, ceresin is a waxy ingredient used as a thickening agent in cosmetics. It can be sensitizing for some skin types.

ceteareth-20. Fatty alcohol that is used to thicken cosmetics and keep ingredients mixed together and stable.

cetearyl alcohol. Fatty alcohol used as an emollient, emulsifier, thickener, and carrying agent for other ingredients. Can be derived naturally, as in coconut fatty alcohol, or synthetically.

cetearyl ethylhexanoate. See cetearyl alcohol.

cetyl acetate. A mixture of cetyl alcohol and acetic acid used as a skin-conditioning agent and emollient.

cetyl alcohol. Fatty alcohol used as an emollient, emulsifier, thickener, and carrying agent for other ingredients. Can be derived naturally, as in coconut fatty alcohol, or synthetically. It is not an irritant and is not related to sd alcohol or ethyl alcohol.

cetyl dimethicone. Silicone polymer that functions as skin-conditioning agent. See silicone.

cetyl esters. Synthetic wax used in cosmetics as a thickening agent and emollient.

cetyl PEG/PPG-10/1-dimethicone. Silicone that functions as a skin-conditioning agent and emulsifier. See silicone.

chamomile. Plant species include Matricaria recutita, Chamomilla recutita, and Matricaria chamomilla. Chamomile tea, brewed from dried flower heads, has been used traditionally for medicinal purposes. The main constituents of the flowers include phenolic compounds, primarily the flavonoids apigenin, quercetin, patuletin, luteolin, and their glucosides. The principal components of the essential oil extracted from the flowers are the terpenoids α-bisabolol and its oxides and azulenes, including chamazulene. Chamomile has moderate antioxidant and antimicrobial activities, and significant anti-platelet activity in vitro. Animal model studies indicate it may have potent anti-inflammatory action, some antimutagenic and cholesterol-lowering activities, as well as antispasmotic and anxiolytic effects. However, human studies are limited, and clinical trials examining the purported sedative properties of chamomile tea are absent. Adverse reactions to chamomile, consumed as a tisane or applied topically, have been reported among those with allergies to other plants in the daisy family (Sources: Phytotherapy Research, July 2006, pages 519–618; www.herbmed.org; European Journal of Drug Metabolism and Pharmacokinetics, October–December 1999, pages 303–308; and Planta Medica, October 1994, pages 410–413).

chaparral extract. There is conflicting research about its efficacy as an anticancer agent, though it does contain a component that has antioxidant properties (Source: Society for Experimental Biology and Medicine, January 1995, pages 6–12; and www.healthwell.com/healthnotes/). When ingested, it may cause liver toxicity (Sources: Molecular and Cellular Biochemistry, June 1999, pages 157–161; Archives of Internal Medicine, April 1997, pages 913–919; and www.quackwatch.com/01QuackeryRelatedTopics/OTA/ota04.html). Topically it can have antimicrobial properties (Source: Journal of Ethnopharmacology, June 1996, pages 175–177).

charcoal. Primarily carbon substance formed by charring organic material in absence of oxygen. One teaspoonful of Activated Charcoal USP has a surface area of more than 10,000 square feet, which gives charcoal unique absorption properties. It also can disinfect wounds.

chaulmoogra oil. Once the treatment for leprosy worldwide due to its antimicrobial properties (Source: Proceedings of the National Academy of Sciences, February 2000, pages 1433–1437). It can be a skin irritant.

chelating agent. Any of numerous ingredients that bind with metal ions or metallic compounds, preventing them from adhering to a surface (such as skin, hair, or clothing) or causing contamination or discoloration, such as in the case of trace amounts of iron. Examples are tetrasodium EDTA and tetrahydroxypropyl ethylenediamine. The EDTA complex is most common because of its broad effectiveness and compatibility with most cosmetic ingredients.

chestnut seed extract. Also known as European chestnut, the extract has a high tannin content, which has astringent and drying properties on skin (Source: American Herbal Products Association’s Botanical Safety Handbook, CRC Press, LLC, 1997). Chestnut seed has no documented beneficial effect on skin.

China clay. See kaolin.

chitosan. Derived from chitin, a polysaccharide found in the exoskeletons of shrimp, lobster, and crabs. It is used widely in pharmaceuticals as a base in formulations. There is also extensive research showing it can be effective in wound healing, as well as having antibacterial and anti-inflammatory properties (Sources: Journal of Pharmacy and Pharmacology, November 2002, pages 1453–1459;Biomaterials, November 2001, pages 2959–2966; International Journal of Food Microbiology, March 2002, pages 65–72; Journal of Pharmacy and Pharmacology, August 2001, pages 1047–1067; and British Journal of Plastic Surgery, October 2000, pages 601–606). See mucopolysaccharide.

chlorella. See algae.

chlorhexidine. Topical antiseptic, it can cause irritation (Source: Toxicology in Vitro, August–October 2001, pages 271–276).

chlorophene. Used as a preservative in cosmetics.

chloroxylenol. Chemical compound used as a disinfectant and preservative due to its action against certain types of bacteria and fungi.

chlorphenesin. Alcohol used as a preservative in cosmetics.

cholecalciferol. Technical name for vitamin D. See vitamin D.

cholesterol. The barrier function of skin depends on the stratum corneum extracellular lipid matrix, which includes ceramides, cholesterol, and free fatty acids. Smaller amounts of cholesterol sulfate and cholesteryl oleate may be present. Cholesterol in cosmetics can help maintain the skin’s normal function. It is also a stabilizer, emollient, and water-binding agent (Source: Journal of Structural Biology, June 2007, pages 386–400). See natural moisturizing factor (NMF).

choline. Part of the vitamin B complex and a constituent of many other biologically important molecules, such as acetylcholine (a neurotransmitter) and lecithin.

chondroitin sulfate. See glycosaminoglycans.

Chondrus crispus. Form of red seaweed. See algae and carrageenan.

chromium hydroxide green. Earth mineral used as a coloring agent/additive and permanently listed (as of 1977) by the FDA for use in cosmetic products.

chromium oxide green. See chromium hydroxide green.

chrysanthemum extract. Can have anti-inflammatory benefit for skin.

Chrysanthemum parthenium extract. See feverfew extract.

Cichorium intybus. Source of a plant extract with antioxidant properties (Source: Archives of Pharmaceutical Research, October 2001, pages 431–436).

Cimicifuga racemosa root extract. See black cohosh.

Cinnamomum. See cinnamon.

Cinnamomum camphora. See camphor.

cinnamon. Can have antimicrobial and antioxidant properties (Sources: Cutaneous and Ocular Toxicology, March 2007, pages 227–233; and Letters in Applied Microbiology, January 2002, pages 27–31), but it can also be a skin irritant (Source: Contact Dermatitis, October 1993, pages 202–205).

citric acid. Extract derived from citrus and used primarily to adjust the pH of products to prevent them from being too alkaline.

Citrullus colocynthis. Bitter apple; considered a skin irritant.

Citrus amara. See orange blossom.

Citrus aurantifolia. See lime.

Citrus aurantium. See orange blossom.

Citrus aurantium extract. Bitter orange extract. It can have antioxidant properties when eaten (Source: Journal of Agricultural Food Chemistry, December 1999, pages 5239–5244); however, used topically its methanol content makes it potentially irritating for skin (Source: Contact Dermatitis, January 1992, pages 9–11).

Citrus medica limonium. See lemon.

clary oil. Used as fragrance; can be a skin irritant or sensitizer.

clay. See bentonite and kaolin.

clove leaf. See clove oil.

clove oil. Potent skin irritant and inflammatory when used repeatedly (Sources: IFA—International Federation of Aromatherapists, www.int-fed-aromatherapy.co.uk; www.naturaldatabase.com; and Contact Dermatitis, March 2002, pages 141–144). Clove oil contains 73% eugenol, a volatile substance that research has shown causes skin-cell death (Source: Cell Proliferation, August 2006, pages 241–248).

clover blossom. Contains eugenol, which can be a skin sensitizer and cause photosensitivity.

clover leaf oil. See clover blossom.

cocamide DEA and MEA. See alkyloamides and diethanolamine.

cocamidopropyl betaine. One of the more gentle surfactants used in skin-care products. See surfactant.

cocamidopropyl hydroxysultaine. Mild surfactant. See surfactant.

cocoa butter. Oil extracted from cocoa beans, used as an emollient and with properties similar to those of other nonfragrant plant oils. See natural moisturizing factor (NMF).

cocoa extract. Can have potent antioxidant properties (Sources: Experimental Biology and Medicine, May 2002, pages 321–329; and Journal of Agricultural Food Chemistry, July 2001, pages 3438–3442).

cocoglycerides. Used as an emollient and thickening agent in cosmetics. See glyceryl ester.

coconut. Has degreasing and cleansing properties, which is why detergent cleansing agents are frequently derived from coconut oil. See surfactant.

coconut oil. Non-volatile plant kernel oil that has emollient properties for skin.

Cocus nucifera. See coconut oil.

Codium tomentosum extract. See algae.

coenzyme Q10. Also known as ubiquinone, it is a vitamin-like substance present in all human cells and responsible for cell protection and production of the body’s energy.

A handful of studies have shown that coenzyme Q10 (CoQ10) may have an effect on skin and the appearance of wrinkles (Sources: Biofactors, November 2005, pages 179–185; and Journal of Cosmetic Dermatology, March 2006, pages 30–38). However, one study was performed in vitro and the other was not placebo-controlled, so there is no way to tell whether other formulations could net the same results.

There is also research showing that sun exposure depletes the presence of CoQ10 in the skin (Sources: Journal of Investigative Dermatology, 2005, volume 125, number 4, pages 12–13; and Journal of Dermatological Science, August 2001, Supplement, pages 1–4). This is not surprising because many of the skin’s components become diminished on exposure to the sun. The latest research suggests that topical application of CoQ10 has antioxidant and anti-inflammatory effects. As such, it is one of many helpful antioxidants for skin, but it is not the only one or the “best” (Sources: Journal of Cosmetic Dermatology, March 2006, pages 30–38; and Biofactors, 2003, pages 289–297).

Coffea arabica extract. Coffea arabica is the coffee plant, and there is research showing that coffee extract has antioxidant properties (Source: Journal of Agricultural and Food Chemistry, June 2002, pages 3751–3756).

Cola acuminata seed extract. See kola nut.

Coleus barbatus. Member of the mint family and also known as forskolin; can be a skin irritant. See counter-irritant.

collagen. Collagen is a type of protein found extensively throughout the body. It supports skin, internal organs, muscles, bone, and cartilage. There are more than 25 types of collagen that occur naturally in the body. Collagen works in tandem with elastin to give skin its texture, structure, and appearance. Sun damage (extrinsic aging) and aging (intrinsic aging) causes collagen in the skin to deteriorate. As a cosmetic ingredient, collagen is derived from animal sources, but plant derivatives that act like collagen (pseudo-collagen) are also used. In any form, collagen is a good water-binding agent. Collagen in cosmetics, regardless of the source, has never been shown to have a direct effect on producing or building collagen in skin.

collagen amino acid. Amino acids hydrolyzed from collagen. These have good water-binding properties for skin. See amino acid and natural moisturizing factor (NMF).

colloidal oatmeal. See oatmeal.

colloidal silver. Refers to ground-up silver suspended in solution. See silver.

colostrum. The thick, yellowish fluid secreted by the mammary glands prior to and during the first few days after birth, before actual milk is produced by the breast. Colostrum is a highly nutritive substance, loaded with proteins, immune-building substances, and growth factors. Colostrum’s primary purpose is to supply antibodies and growth factors to help newborns fight viruses and bacteria and to jump-start the growth of muscle, bone, and tissue. There is some research showing it has benefits when applied topically for wound healing, but there is also research showing that it was not helpful. The source of colostrum in supplements and skin-care products is bovine (Sources: Journal of Reproductive Immunology, July 1998, pages 155–167; Indian Journal of Pediatrics, July 2005, pages 579–581; Cells Tissues Organs, January 2000, pages 92–100; Australasian Biotechnology, July–August 1997, pages 223–228; and Journal of Dermatologic Surgery Oncology, June 1985, pages 617–622).

coltsfoot. According to The PDR Family Guide to Natural Medicines & Healing Therapies, 1998 and a German Commission E Monograph, 1998 coltsfoot is potentially carcinogenic due to its pyrrolizidine alkaloid content, and it is not recommended for repeated use on skin.

comfrey extract. Several studies have shown that comfrey extract can have carcinogenic or toxic properties when taken orally. It is a major problem for the body when consumed orally because of pyrrolizidine alkaloids. These compounds occur naturally in every part of the comfrey plant, and are absorbed through the skin, where they cause problems when the liver attempts to metabolize them. It is these metabolites (referred to as pyrroles) that are highly toxic (Sources: www.naturaldatabase.com; International Journal of Molecular Sciences, 2002, pages 948–964; and http://www.ansci.cornell.edu/plants/toxicagents/
alkaloids/pyrrolizidine.html).

Topical application of comfrey has anti-inflammatory properties, but is recommended only for short-term use and only then if you can be sure the amount of pyrrolizidine alkaloids is less than 100 micrograms per application—something that would be impossible to determine without sophisticated testing equipment, making comfrey an ingredient to avoid. The alkaloid content makes it a potential skin irritant (Sources: Chemical Research in Toxicology, November 2001, pages 1546–1551; and Public Health Nutrition, December 2000, pages 501–508).

Commiphora myrrha extract. See myrrh.

coneflower. Another name for echinacea; has soothing properties.

Copaifera officinalis. See balsam peru.

copper gluconate. Copper is an important trace element for human nutrition. The body needs copper to absorb and utilize iron, and copper is also a component of the powerful antioxidant enzyme superoxide dismutase. Copper supplements have been shown to increase superoxide dismutase levels in humans (Source: Healthnotes Review of Complementary and Integrative Medicine, www.healthnotes.com). The synthesis of collagen and elastin is in part related to the presence of copper in the body, and copper is also important for many other processes. For example, there is research showing that copper is effective for wound healing and as an antioxidant (Sources: British Journal of Dermatology, January 1999, pages 26–34;Journal of Clinical Investigation, November 1993, pages 2368–2376; Biomedical Research on Trace Elements, 2005, volume 16, number 4, pages 302–305; and Federation of European Biochemical Sciences Letter, October 1988, pages 343–346). See superoxide dismutase.

copper peptides. See copper gluconate.

copper sulfate. Effective for topical wound healing, but there is no research showing it has any impact when used in skin-care products (Source: American Journal of Physiology Heart Circulation and Physiology, May 2002, pages 1821–1827).

Corallina officinalis extract. See algae.

coriander. Herb and spice plant, the source of a fragrant component; it can be a potential skin irritant (Source: www.naturaldatabase.com). It also may have some antibacterial and antifungal properties, but these properties have not been established for topical use on skin (Source: Journal of Food Protection, July 2001, pages 1019–1024).

corn oil. Emollient oil with properties similar to those of other nonfragrant plant oils (Source: British Journal of Dermatology, June 1994, pages 757–764).

cornflower. Can have anti-inflammatory properties (Source: Journal of Ethnopharmacology, December 1999, pages 235–241).

cornmint. Also known as wild mint; it can be a skin irritant. See counter-irritant.

cornstarch. Starch obtained from corn and sometimes used as an absorbent in cosmetics instead of talc. However, when cornstarch becomes moist, it can promote fungal and bacterial growth (Source: www.radiation-oncology.com/homecare/html/skin_13.htm).

Cornus extract. See dogwood.

Corylus americana. See hazelnut oil.

Corylus avellana. See hazelnut oil.

coumarin. Organic compound found in plants and derived from the amino acid phenylalanine. It creates the fragrance in fresh-mowed hay. More than 300 coumarins have been identified from natural sources, especially green plants. These varying substances have disparate pharmacological, biochemical, and therapeutic applications. However, simple coumarins are potent antioxidants (Sources: Journal of Natural Products, September 2001, pages 1238–1240; Chemistry and Physics of Lipids, December 1999, pages 125–135; and General Pharmacology, June 1996, pages 713–722).

counter-irritant. Ingredients such as menthol, peppermint, camphor, and mint are counter-irritants (Sources: Archives of Dermatologic Research, May 1996, pages 245–248; and Code of Federal Regulations Title 21—Food and Drugs, revised April 1, 2001, CITE: 21CFR310.545, www.fda.gov). Counter-irritants are used to induce local inflammation for the purpose of relieving inflammation in deeper or adjacent tissues. In other words, they substitute one kind of inflammation for another, which is never good for skin. Irritation or inflammation, no matter what causes it or how it happens, impairs the skin’s immune and healing response (Source: Skin Pharmacology and Applied Skin Physiology, November–December 2000, pages 358–371). And although your skin may not show it or doesn’t react in an irritated fashion, if you apply irritants to your skin the damage is still taking place and is ongoing, so it adds up over time (Source: Skin Research and Technology, November 2001, pages 227–237).

cranberry seed extract. Extract of the cranberry fruit. Natural components known as proanthocyanidins are responsible for this extract’s antioxidant and anti-inflammatory properties (Source: www.naturaldatabase.com).

cranberry seed oil. Extract derived from the seed of this red berry; the oil (which is not red) has potent antioxidant ability because it is a rich source of polyphenols (Source: Journal of Agricultural and Food Chemistry, November 2, 2005  , pages 8485—8491). See antioxidant.

Crataegus monogina extract. See hawthorn extract.

creatinine. Compound formed by the metabolism of the amino acid creatine. Creatine resides primarily in muscle tissue and blood and is normally excreted in the urine as creatinine. Both creatine and creatinine are cell-signaling ingredients in the body. Theoretically, they should perform a similar function when applied topically, but there is no research to support this. Research on oral supplementation with creatinine has had mixed or unimpressive results, particularly for those who take it to build lean muscle mass (Source: www.naturaldatabase.com).

cucumber extract. Claims of cucumber having anti-inflammatory or soothing properties are anecdotal, as there is no research to support this contention.

Cucumis sativus extract. See cucumber extract.

Curcuma longa root. See turmeric.

curcumin. Potent antioxidant and anti-inflammatory spice that can be effective in wound healing (Sources: Biochemical Pharmacology, August 2007;Journal of Trauma, November 2001, pages 927–931; and Advances in Experimental Medicine and Biology, 2007, pages 1–595). See turmeric.

Cyamopsis tetragonoloba. See guar gum.

cyanocobalamin. See vitamin B12.

cyclamen aldehyde. Synthetic fragrant component in products; it can be a skin irritant.

cyclohexasiloxane. See silicone.

cyclomethicone. Silicone with a drier finish than dimethicone. See silicone.

cyclopentasiloxane. See silicone.

Cymbopogon citrates. See lemongrass extract.

Cymbopogon martini. See geranium extract.

cysteine. See amino acid.

cystine. See amino acid.

cytochrome. Protein found in blood cells that, with the aid of enzymes, serves a vital function in the transfer of energy within cells. There are three types of cytochromes, indicated by A, B, or C, with cytochrome C being the most stable. However, because cytochromes require a complex process that is triggered by a sequence of other components to be effective in their function of cellular respiration, they serve no function alone when applied topically on skin.

cytokines. Diverse, potent, and extremely complex chemical messengers secreted by the cells of the immune system. They stimulate the production of other substances to help protect the body. Cytokines encourage cell growth, promote cell activation, direct cellular traffic, and destroy target cells—including cancer cells. Interleukins, transforming growth factor, and interferon are types of cytokines. It is also important to note that cytokines can also have unwanted, potentially serious side effects (Sources: www.medlineplus.com; and the National Cancer Institute, www.nci.nih.gov or www.cancer.gov).