Skin Care Cosmetics Ingredients Glossary

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.

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

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. 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.

Calcium Silicate Anticaking and opacifying agent; absorbent. Used in face powders, blushers and bath salts.

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. 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. See counter-irritant.

Camomile Oil Distilled from the small yellow flowers of several varieties of Camomile, including German (Matricaria chamomilla) and Roman (Anthemis nobilis). German Camomile contains a high percentage of Azulene, a powerful healer that is extremely soothing to the skin. In aromatherapy, Camomile is used to balance female energy and reproductive organs.

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 . 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 .

carnosic acid. Component of rosemary that is a potent antioxidant

carnosine. Composed of amino acids, it has anti-inflammatory and antioxidant properties. There is some research showing it has antiglycation properties

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.

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. 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.

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. 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.

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.

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.

cherry extract. Also known as wild cherry and sweet cherry, this fruit is a natural source of vitamin C and antioxidant compounds known as anthocyanins and polyphenols. Although cherry is considered a nutritious fruit, there is no research pertaining to its efficacy when used in skin-care products, though it does add fragrance (Source: www.naturaldatabase.com).

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.

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. 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.

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. Clove oil contains 73% eugenol, a volatile substance that research has shown causes skin-cell death.

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

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. 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. 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” .

Coffea arabica extract. Coffea arabica is the coffee plant, and there is research showing that coffee extract has antioxidant properties.

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.

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.

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.

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. 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. 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.

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.

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.

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. 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. 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.

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 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.

cucumber extract. (Cucumis Sativus). It is a natural anti-inflammatory. Works as a mild astringent, yet is gently cooling and soothing and can help reduce puffiness of the skin.

Cucumis sativus extract. See cucumber extract.

Cucurbitea Peponis. See pumpkin

Curcuma longa root. See turmeric.

curcumin. Potent antioxidant and anti-inflammatory spice that can be effective in wound healing. 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.