Acacia senegal. Herb that can have anti-inflammatory properties, but that is used primarily as a thickening agent. See gums.

Accutane. Trade name of prescription-only anti-acne drug that is taken orally. Active ingredient is isotretinoin, which is derived from vitamin A. This drug works by essentially stopping oil production in sebaceous glands (the oil-producing structures of the skin) and literally shrinking these glands to the size of a baby’s (Source: Dermatology, 1997; volume 195, Supplemental 1:1–3, pages 38–40). This prevents sebum (oil) from clogging the hair follicle, mixing with dead skin cells, and rupturing the follicle wall to create an environment where the bacterium (Propionibacterium acnes) can thrive, which can result in pimples or cysts. Relatively normal oil production resumes when treatment is completed; although the sebaceous glands may slowly begin to enlarge again, they rarely become as large as they were before treatment. “Because of its relatively rapid onset of action and its high efficacy with reducing more than 90% of the most severe [acne] inflammatory lesions, Accutane has a role as an effective treatment in patients with severe acne that is recalcitrant to other therapies” (Source: Journal of the American Academy of Dermatology, November 2001, Supplemental, pages 188–194).

Accutane is controversial, however, for several reasons, but principally because of its most insidious side effect—it has been proven to cause severe birth defects in nearly 90% of the babies born to women who were pregnant while taking it. Other commonly reported, although temporary, side effects of Accutane include dry skin and lips, mild nosebleeds (the inside of your nose can get really dry for the first few days), hair loss, aches and pains, itching, rash, fragile skin, increased sensitivity to the sun, headaches, and peeling palms and hands. More serious, although much less common, side effects include severe headaches, nausea, vomiting, blurred vision, changes in mood, depression, severe stomach pain, diarrhea, decreased night vision, bowel problems, persistent dryness of eyes, calcium deposits in tendons, an increase in cholesterol levels, and yellowing of the skin. However, there is current research indicating that depression does not occur during the course of taking Accutane (Sources: Canadian Journal of Clinical Pharmacology, June 2007, pages 277–233; Psychological Reports, December 2006, pages 897–906; European Journal of Dermatology, September–October, 2006, pages 565–571; and Journal of Drugs in Dermatology, May 2006, pages 467–468).

acetone. Strong solvent used in nail polish removers.

acetyl carnitine HCL. See L-carnitine.

acetyl glucosamine. Amino acid sugar and primary constituent of mucopolysaccharides and hyaluronic acid that has good water-binding properties for skin. In large concentrations it can be effective for wound healing. There is research showing that chitosan (which is composed of acetyl glucosamine) can help wound healing in a complex physiological process (Sources: Cellular-Molecular-Life-Science, February 1997, pages 131–140; and Biomaterials, June 2001, pages 1667–1673). However, the amount used in those studies was significantly greater than the amount used in cosmetics. In terms of exfoliation, the research that does exist was done by Proctor & Gamble (Source: Journal of the American Academy of Dermatology, February 2007, Supplement 2, page AB169). Further, there is no research demonstrating that wrinkles are related to wounds.

acetyl hexapeptide-3. Synthetically derived peptide used in a wide range of skin-care and makeup products, especially those claiming to have a muscle-relaxing effect similar to Botox injections. These claims typically have to do with relaxing muscle contractions when making facial expressions, thus reducing the appearance of expression lines. The company that sells acetyl hexapeptide-3 (trade name Argireline), Centerchem (www.centerchem.com), is based in Spain. According to their Web site, “Argireline works through a unique mechanism which relaxes facial tension leading to a reduction in superficial facial lines and wrinkles with regular use. Argireline has been shown to moderate excessive catecholamines release.” The truth of this claim about the effects of topical application of Argireline is based only on information from Centerchem; there is no published research substantiating any use of Argireline topically on skin.

Catecholamines are compounds in the body that serve as neurotransmitters such as epinephrine, adrenaline, and dopamine. Epinephrine prepares the body to handle emergencies such as cold, fatigue, and shock. A deficiency of dopamine in the brain is responsible for the symptoms of Parkinson’s disease. These actions are not something you want a cosmetic to inhibit or reduce.

If acetyl hexapeptide-3 really worked to relax facial muscles, it would work all over the face (assuming you’re using the products as directed). If all the muscles in your face were relaxed you’d have sagging, not youthful, skin, not to mention that it also would affect your hand (you apply it with your fingers), which would prevent you from picking up a cup or holding the steering wheel of your car. Despite all the fear about Botox that is espoused by companies featuring this peptide in their “works like Botox” products, there is considerably more efficacy, usage, and safety documentation available for Botox.

Despite the claims made for acetyl hexapeptide-3 (Argireline), there is a clinical study that shows that this ingredient is not even remotely as effective as Botox in reducing wrinkles (Sources: www.cremedevie.com/clinical_details.htm; and International Journal of Cosmetic Science, October 2002). It is also interesting to note that even Botox when applied topically on skin has no impact on the skin or muscles in any way shape or form! (Source: Cosmetic Dermatology, July 2005, pages 521–524.) See peptide.

acetylated castor oil. Used as an emollient and thickening agent in cosmetics. See glyceryl ester.

acetylated lanolin. Emollient derived from lanolin. See lanolin.

acetylated lanolin alcohol. Ester of lanolin alcohol used as an emollient and occlusive agent. Esters are compounds formed from an alcohol and an acid with the elimination of water, and are common cosmetic ingredients.

acetylated palm kernel glycerides. Emollient and thickening agents used in cosmetics. See glyceryl ester.

Achillea millefolium. See yarrow extract.

acid. Anything with a pH lower than 7 is acidic; a pH above 7 is alkaline. Water has a pH of 7. Skin has an average pH of 5.5.

acne soap. Soaps that often contain antibacterial ingredients, and that are often overly drying and irritating to skin due to the cleansing agents they contain. A study reported in Infection (March–April 1995, pages 89–93) demonstrated that “in the group using soap the mean number of inflammatory [acne] lesions increased…. Symptoms or signs of irritation were seen in 40.4% of individuals….” Furthermore, if the antibacterial agents are in a cleanser, any benefit is washed down the drain.

acrylate. See film-forming agent.

acrylate copolymer. See film-forming agent.

acrylates/C10-30 alkyl acrylate crosspolymer. See film-forming agent.

Actaea racemosa. See black cohosh.

active ingredient. The active ingredients list is the part of a cosmetic, drug, or pharmaceutical ingredient label that must adhere to specific FDA-mandated regulations. Active ingredients must be listed first on an ingredient label. The amount and exact function of each active ingredient is controlled and must be approved by the FDA. Active ingredients are considered to have a pharmacological altering effect on skin, and these effects must be documented by scientific evaluation and approved by the FDA. Active ingredients include such substances as sunscreen ingredients, skin-lightening agents, and benzoyl peroxide. See inactive ingredient.

adenosine triphosphate. Organic compound of adenosine that is formed by hydrolysis of yeast nucleic acids. All living things need a continual supply of energy to function. Animals obtain energy by oxidizing foods, plants obtain energy by chlorophyll’s interaction with sunlight. However, before the energy can be used, it must first be changed into a form that the organism can readily use. This special form, or carrier, of energy is the molecule adenosine triphosphate (ATP). In humans, ATP is the major energy source within the cell that drives a number of biological processes such as protein synthesis. The cell breaks down ATP by hydrolysis to yield adenosine diphosphate (ADP), which is then further broken down to yield adenosine monophosphate (AMP). Research into topically applied adenosine triphosphate is just beginning, but it appears to have strong potential as a cell-communicating ingredient and as an inflammation modulator (Sources: The Journal of Investigative Dermatology, volume 124, issue 4, April 2005, pages 756–763; and Journal of Cutaneous Medicine and Surgery, volume 8, issue 2, March–April 2004, pages 90–96). See cell-communicating ingredients.

advanced glycation endproduct. Advanced glycation endproducts (AGEs) are formed by the body’s major fuel source, namely glucose. This simple sugar is essential for energy, but also can bind strongly to proteins (the body’s fundamental building blocks), forming abnormal structures—AGEs—that progressively damage tissue elasticity. Once AGEs are generated, they begin a process that prevents many systems from behaving normally by literally causing tissue to cross-link and become hardened (Source: Proceedings of the National Academy of Sciences, March 14, 2000 , pages 2809–2813). The theory is that by breaking these AGE bonds you can undo or stop the damage they cause. There are studies showing that aminoguanidine and carnosine are AGE inhibitors that can prevent glucose cross-linking of proteins and the loss of elasticity associated with aging and diabetes; however, many other substances are potential candidates as AGE inhibitors as well. One study examined over 92 substances, and 29 of them showed some degree of inhibitory activity, with 9 compounds proving to be 30 to 40 times stronger than aminoguanidine (Source: Molecular Cell Biology Research Communications, June 2000, pages 360–366). AGEs and free-radical damage may be inextricably linked (Sources: European Journal of Neuroscience, December 2001, page 1961; and Neuroscience Letters, October 2001, pages 29–32), but none of the studies show that there is any relevance when it comes to topical application of these substances as they are included in cosmetics.

Aerocarpus santalinus. See red sandalwood.

Aesculus hippocastanum. See horse chestnut extract.

agar. An extract from seaweed used as an emulsifier and thickening agent. See algae.

Agaricus bisporus extract. Extract of mushroom that is thought to help regulate skin cell production by inhibiting cell growth, particularly for use in psoriasis, but research in this regard is mixed (Sources: Free Radical Research, January 2006, pages 31–39; and British Journal of Dermatology, January 1999, pages 56–60). Internally, there is research showing it can inhibit the growth of breast cancer cells and colon cancer cells (Source: Cancer Research, October 1993, pages 4627–4632).

AGE. See advanced glycation endproduct.

Agrimonia eupatoria leaf extract. Plant extract that research shows inhibits the hepatitis B virus and has antioxidant properties. Whether or not it has benefit when applied topically is not known. There is no research showing it to be effective for cellulite (Sources: Phytotherapy Research, April 2005, pages 355–358; and Journal of Ethnopharmacology, January 2005, pages 145–150).

AHA. Acronym for alpha hydroxy acid. AHAs are derived from various plant sources or from milk. However, 99% of the AHAs included in cosmetics are synthetic. In low concentrations (less than 3%) AHAs work as water-binding agents. At concentrations over 4% and in a base with an acid pH of 3 to 4, these can exfoliate skin cells by breaking down the substance in skin that holds skin cells together. The most effective and well-researched AHAs are glycolic acid and lactic acid. Malic acid, citric acid, and tartaric acid may also be effective, but are less stable and less skin-friendly; there is little research showing that they have any benefit for skin.

AHAs may irritate mucous membranes and cause irritation. However, AHAs are widely used for therapy of photodamaged skin, and also have been reported to normalize hyperkeratinization (over-thickened skin) and to increase viable epidermal thickness and dermal glycosaminoglycans content. A vast amount of research has substantially described how the aging process affects the skin and has demonstrated that many of the unwanted changes can be improved by topical application of AHAs, including glycolic and lactic acid (Sources: Plastic and Reconstructive Surgery, April 2005, pages 1156–1162; Cutis, August 2001, pages 135–142; Journal of the European Academy of Dermatology and Venereology, July 2000, pages 280–284; American Journal of Clinical Dermatology, March-April 2000, pages 81–88; Skin Pharmacology and Applied Skin Physiology, May-June 1999, pages 111–119; Dermatologic Surgery, August 1997, pages 689–694 and May 2001 pages 1–5; Journal of Cell Physiology, October 1999, pages 14–23; and British Journal of Dermatology, December 1996, pages 867–875).

Because AHAs exfoliate sun-damaged skin from the surface of the skin, and because this layer imparts some (albeit minimal) sun protection for skin, there is a risk of increased sun sensitivity after using an AHA (Source: Photodermatology, Photoimmunology, and Photomedicine, February 2003, pages 21–27). However, wearing a sunscreen eliminates this risk.

Ahnfeltia concinna extract. See algae.

Ajuga turkestanica extract. Asian plant extract that limited in vitro research has shown is an effective ingredient to increase aquaporin activity in skin cells (Sources: Journal of Drugs in Dermatology, June 2007, Supplement, pages 20-24; and European Journal of Dermatology, November/December 2002, pages 25-26). See aquaporin.

alanine. See amino acid.

albumin. Found in egg white, and can leave a film over skin. It can constrict skin temporarily, making it look smoother for a brief period, but it can also cause irritation and is not helpful for skin.

Alchemilla vulgaris. Plant with antimicrobial properties. Its high tannin content can cause skin irritation (Source: Journal of Ethnopharmacology, July 2000, pages 307–313).

alcloxa. Technically known as aluminum chlorhydroxy allantoinate, alcloxa has constricting properties that can be irritating for skin.

alcohol. Group of organic compounds that have a vast range of forms and uses in cosmetics. In benign form they are glycols used as humectants that help deliver ingredients into skin. When fats and oils (see fatty acid) are chemically reduced, they become a group of less-dense alcohols called fatty alcohols that can have emollient properties or can become detergent cleansing agents. When alcohols have low molecular weights they can be drying and irritating. The alcohols to be concerned about in skin-care products are ethanol, denatured alcohol, ethyl alcohol, methanol, benzyl alcohol, isopropyl alcohol, and sd alcohol, which not only can be extremely drying and irritating to skin, but also can generate free-radical damage (Sources: “Skin Care—From the Inside Out and Outside In,” Tufts Daily, April 1, 2002; eMedicine Journal, May 8, 2002, volume 3, number 5, www.emedicine.com; Cutis, February 2001, pages 25–27; Contact Dermatitis, January 1996, pages 12–16; and http://pubs.niaaa.nih.gov/publications/arh27-4/277-284.htm). In a product where these ingredients are at the top of the ingredient list, they will be problematic for all skin types; when they are at the bottom of an ingredient list, there most likely is not enough present to be a problem for skin.

Aleurites fordii oil. Oil from the Polynesian tung tree, which may have antimicrobial properties for skin (Source: Journal of Ethnopharmacology, November 1995, pages 23–32).

alfalfa extract. Can be an antioxidant in skin-care products (Source: Journal of Agricultural Food Chemistry, January 2001, pages 308–314).

algae. Algae are very simple, chlorophyll-containing organisms in a family that includes more than 20,000 different known species. A number of species have been used for drugs, where they work as anticoagulants, antibiotics, antihypertensive agents, blood cholesterol reducers, dilatory agents, insecticides, and anti-tumorigenic agents. In cosmetics, algae act as thickening agents, water-binding agents, and antioxidants. Some algae are also potential skin irritants. For example, the phycocyanin present in blue-green algae has been suspected of allergenicity and of causing dermatitis on the basis of patch tests (Source: Current Issues in Molecular Biology, January 2002, pages 1–11). Other forms of algae, such as Irish moss and carrageenan, contain proteins, vitamin A, sugar, starch, vitamin B1, iron, sodium, phosphorus, magnesium, copper, and calcium. These are all beneficial for skin, either as emollients or antioxidants (Source: Journal of Agricultural Food Chemistry, February 2002, pages 840–845). However, the claims that algae can stop or eliminate wrinkling, heal skin, or provide other elaborate benefits are unsubstantiated.

algin. Brown algae. See algae.

aliphatic hydrocarbon. Hydrocarbon contained in natural gas and mineral oils. It is a synthetic fluid with varying properties that range from solvent to slip agent. See slip agent and solvent.

alkaline. Anything with a pH higher than 7 is alkaline; a pH below 7 is acidic. Water has a pH of 7; skin has an average pH of 5.5. Skin irritation can be caused by products with a pH of 8 or higher (Sources: eMedicine Journal, January 7, 2002, volume 3, number 1, www.emedicine.com; Cutis, December 2001, Supplemental, pages 12–19; and Contact Dermatitis, April 1996, pages 237–242). Also, research indicates that the bacterium that causes acne, Proprionibacterium acnes, proliferates when the skin is more alkaline (Sources: Infection, March–April 1995, pages 89–93; and Journal of Antimicrobial Chemotherapy, September 1994, pages 321–330).

alkyloamides. Identified on skin-care product labels as DEA (See diethanolamine), triethanolamine (TEA), and monoethanolamine (MEA), these are used primarily for their foaming ability in shampoos, but can also be used as thickening or binding agents. They can be skin irritants. In addition, alkyloamides contain a free amine that can combine with formaldehyde-releasing preservatives in cosmetics, and there is concern that they may form carcinogens.

allantoin. By-product of uric acid extracted from urea and considered an effective anti-
irritant.

all-trans retinoic acid. Active ingredient in Retin-A and Renova. See tretinoin.

almond oil. Non-volatile oil extracted from the seeds of almonds and used as an emollient. See natural moisturizing factor (NMF).

Aloe barbadensis. See aloe vera.

aloe extract. See aloe vera.

aloe juice. See aloe vera.

aloe vera. There is no real evidence that aloe vera (Aloe barbadenis) helps the skin in any significant way. An article in the British Journal of General Practice (October 1999, pages 823–828) stated that “Topical application of aloe vera is not an effective preventative for radiation-induced injuries…. Whether it promotes wound healing is unclear…. Even though there are some promising results, clinical effectiveness of oral or topical aloe vera is not sufficiently defined at present.” There is research indicating that isolated components of aloe vera, such as glycoprotein, can have some effectiveness for wound healing and as an anti-irritant (Sources: Journal of Ethnopharmacology, December 1999, pages 3–37; Free-Radical Biology and Medicine, January 2000, pages 261–265; and British Journal of Dermatology, October 2001, pages 535–545). However, when mixed into a cosmetic product, it is doubtful those qualities remain, although it may still play a role in binding moisture to skin (Source: Skin Research and Technology, November 2006, pages 241–246).

In pure form, aloe vera’s benefits on skin are probably its lack of occlusion and the refreshing sensation it provides. Aloe serves as a water-binding agent for skin due to its polysaccharide (complex carbohydrate) and sterol content. (An example of a sterol that’s beneficial for skin is cholesterol) Although research has shown aloe also has anti-inflammatory, antioxidant, and antibacterial qualities, no study has proven it to be superior to other ingredients with similar properties, including vitamin C, green tea, pomegranate, and many other antioxidants (Source: www.naturaldatabase.com).

alpha bisabolol. See bisabolol.

alpha glucan oligosaccharide. Emollient used in cosmetics that also has water-binding properties. See mucopolysaccharide.

alpha hydroxy acid. See AHA.

alpha lipoic acid. Enzyme that, when applied topically on skin, can be a very good antioxidant. While studies of alpha lipoic acid do exist, none of them were carried out on people, and none were double-blind or placebo-controlled to evaluate effects on wrinkling (Source: Clinical & Experimental Dermatology, October 2001, pages 578–582). Most of the research was done on human dermal fibroblasts in vitro (test tube) in cell-culture systems. In vitro results are interesting, but it’s not known if the results translate to human skin. These models do mimic human skin, but something that mimics human skin is not the same as living skin. There is research showing that alpha lipoic acid, when taken orally, can help prevent cellular damage via its antioxidant properties (Source: Annals of the New York Academy of Sciences, April 2002, pages 133–166). Again, whether or how that translates into an effect on skin is unclear. It is clear from the research that alpha lipoic acid is a potent antioxidant, but this isn’t the only one and, to date, there are lots of great antioxidants, whether in the form of food, supplements, or applied topically to skin. See antioxidant.

alpha-tocopherol. See vitamin E.

Alteromonas ferment extract. Alteromonas is a gram-negative bacteria found in seawater. It may have water-binding properties for skin, but there is scant research supporting this or any other benefit for skin.

Althaea rosea. See mallow.

Althea officinalis. Latin name for the marshmallow plant. See mallow.

alumina. Aluminum oxide, which is used as an abrasive, a thickening agent, and an absorbent in cosmetics.

aluminum chlorohydrate. Chemically a salt, and used in antiperspirants, it can be extremely irritating on abraded skin. In terms of a risk of breast cancer related to underarm deodorant, in October 2002, a study conducted at the Seattle-based Fred Hutchinson Cancer Research Center, published in the Journal of the National Cancer Institute, looked at the issue of underarm deodorant use and breast cancer. The study compared the use of underarm deodorant in 810 women who had been diagnosed with breast cancer, and 793 women who were not affected by the disease. When the two groups were compared, researchers found no evidence of an increased risk of breast cancer linked to using an antiperspirant or deodorant, or using an antiperspirant or deodorant after shaving with a traditional razor blade. In short, the researchers believed their study proved there was no link between underarm deodorants and breast cancer risk.

aluminum magnesium silicate. Salt that has absorbent properties.

aluminum powder. Metallic element used as a coloring agent. It is composed of finely ground particles of aluminum. Permanently listed (since 1977) by the FDA as a safe coloring additive.

aluminum silicate. Salt that has absorbent and abrasive properties.

aluminum starch octenylsuccinate. Powdery thickening agent, absorbent, and anticaking agent used in cosmetics.

aluminum sulfate. Topical disinfectant and typical ingredient in deodorants. It can be a skin irritant.

amino acid. Fundamental constituents of all proteins found in the body, such as: alanine, arginine, asparagine, aspartic acid, cysteine, cystine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, serine, threonine, tryptophan, tyrosine, and valine. Some of these amino acids can be synthesized by the body; others, the essential amino acids must be obtained from protein in the diet. In skin-care products, these types of ingredients act primarily as water-binding agents, and some have antioxidant properties and wound-healing abilities as well. However, these substances cannot affect, change, or rebuild wrinkles. Whether the protein in a skin-care product is derived from an animal or a plant, the skin can’t tell the difference. See protein and natural moisturizing factor (NMF).

aminobutyric acid. Amino acid that has water-binding properties for skin and may be an anti-inflammatory. It supposedly also increases growth hormone when taken orally, but the only support for this is a single obscure study that was conducted more than two decades ago on fewer than 20 subjects, and the results have yet to be replicated by other scientists.

aminomethyl propanediol. Used to adjust pH in cosmetics.

aminomethyl propanol. Used in cosmetics at concentrations of 1% or less to adjust pH.

aminophylline. Pharmaceutical ingredient present in prescription bronchodilators (medications designed to open blocked air passageways in the lungs) and present in some cellulite lotions and creams. Aminophylline gained notoriety as an ingredient in cellulite creams as a result of a study published in Obesity Research (November 1995, Supplemental, pages 561S–568S). The validity of this research was called into question because one of its authors was marketing an aminophylline cream being sold at the time, and thus was not considered an objective investigator. Also, the number of participants in the study was small, and most of them also were dieting and exercising at the same time that they were applying the aminophylline cream (Source: Annals of Pharmacotherapy, March 1996, pages 292–293).

Doubt about aminophylline’s value also was revealed in research published in Plastic and Reconstructive Surgery (September 1999, pages 1110–1114), which described a double-blind study that compared the effectiveness of three different treatments for cellulite on three separate groups of women. One investigated twice-daily application of aminophylline cream compared with a placebo; another twice-weekly treatment using endermologie (a machine rolled over the skin’s surface, which has been claimed to get rid of cellulite) on one leg and nothing on the other; and a third combining endermologie on both legs with the same cream regimen used by the first group. “No statistical difference existed in measurements between legs for any of the treatment groups…. [Even] the best subjective assessment, by the patients themselves, revealed that only 3 of 35 aminophylline-treated legs and 10 of 35 [e]ndermologie-treated legs [felt] their cellulite appearance improved.” There is no other research showing this to be helpful, and the risk of absorption and bronchial involvement when applied topically remains unclear.

ammonium chloride. Alkaline salt used as a pH balancer in skin-care products; it is not used in concentrations that would be problematic for skin.

ammonium glycolate. Synthetic form of glycolic acid used as a pH adjuster and exfoliant. It is sometimes paired with regular glycolic acid to maintain the pH in a range that allows exfoliation.

ammonium laureth sulfate. Can be derived from coconut; used primarily as a detergent cleansing agent and is considered gentle and effective. See surfactant.

ammonium lauryl sulfate. Can be derived from coconut; used primarily as a detergent cleansing agent and is considered gentle and effective. See surfactant.

amniotic extract or fluid. There is research showing that pure concentrations of amniotic fluid (human) have some benefit for wound healing (Sources: Journal of Hand Surgery, March 2001, pages 332–339; and Cornea, September 1996, pages 517–524). However, there is no research showing that amniotic fluid is effective for wrinkles or other skin-care needs, or when diluted in cosmetic formulations.

amodimethicone. See silicone.

amygdalic acid. See mandelic acid.

amyl cinnamate. Fragrant component.

amyl salicylate. Fragrant component.

amyris oil. Fragrant oil. It has no other known benefit for skin.

Anacyclus pyrethrum. See pellitory.

Anacystis nidulans extract. See algae.

Ananas sativus fruit extract. See pineapple extract.

andiroba oil. Extracted from the Brazilian mahogany tree; it has anti-inflammatory properties (Source: www.rain-tree.com/andiroba.htm).

Angelica archangelica root oil. Volatile oil obtained from the angelica plant. The oil contains chemical constituents that can be phototoxic, including bergapten, imperatorin, and xanthotoxin. Although some components of angelica oil have antioxidant ability, it is a risky ingredient to use on skin if it is exposed to sunlight (Sources: www.naturaldatabase.com; and Journal of Agricultural and Food Chemistry, March 2007, pages 1737–1742).

Angelica polymorpha sinensis root extract. See dong quai.

anisaldehyde. Synthetic fragrance used in cosmetics.

anise. Also known as aniseed, it can have potent antioxidant and antibacterial properties (Source: Phytotherapy Research, February 2002, pages 94–95), but its fragrant component makes this a potential skin irritant, and it can cause photosensitivity (Source: www.naturaldatabase.com).

annato extract. Natural plant colorant derived from the flesh surrounding the seed of Bixa orellana, a shrub native to South America. It produces a deep yellow-orange to red color.

Anthemis nobilis flower extract. See chamomile.

anthocyanin. Group of naturally occurring substances found in plants that give fruits, vegetables, and plants their unique color. Derived from two Greek words meaning plant and blue, anthocyanins are the pigments that make blueberries blue, raspberries red, and so on. Anthocyanins are potent antioxidants, and there is research showing that plants rich in anthocyanins (e.g., pomegranates and grapes) have anti-tumor properties. More than 300 different anthocyanins have been identified (Sources: Journal of Agricultural Food Chemistry, January 2006, pages 319–327; and International Journal of Cancer, January 2005, pages 423–433).

antibacterial. Any ingredient that destroys or inhibits the growth of bacteria; in the case of skin-care products, particularly the bacteria that cause blemishes.

anti-inflammatory. Any ingredient that reduces certain signs of inflammation, such as swelling, tenderness, pain, irritation, or redness.

anti-irritant. Any ingredient that reduces certain signs of inflammation, such as swelling, tenderness, pain, itching, or redness. For more information, refer to Chapter Two, Healthy Skin: Rules to Live By.

antioxidant. For a detailed explanation of antioxidants, please refer to Chapter Two, Healthy Skin: Rules to Live By. See free-radical damage.

apricot kernel. Seed that, especially when finely ground, is a natural exfoliant.

apricot kernel oil. Emollient plant oil pressed from the seeds of apricots, and similar to other nonfragrant plant oils. See natural moisturizing factor (NMF).

aquaporin. Group of ten different proteins that form water channels in living things to regulate the water content of skin and other organs. Aquaporin 3 is abundant in the skin of humans and animals. In relation to aquaporin 3, glycerol absorption and transportation through these “water channels” is fundamental to preventing water loss and increasing skin’s elasticity (Sources: Proceedings of the National Academy of Sciences of the United States, June 10, 2003, pages 7360–7365; and The Journal of Experimental Biology, October 2003, page 3).

arachidic acid. Derived from peanut oil and used as an emollient and thickening agent in cosmetics.

arachidonic acid. Produced from phospholipids and fatty acids. There is research showing that this is potentially unsafe and mutagenic when used topically, though more study is needed to decide this conclusively (Sources: Journal of Cellular and Molecular Life Sciences, May 2002, pages 799–807; and Journal of Environmental Pathology, Toxicology, and Oncology, 2002, volume 21, number 2, pages 183–191).

arachidyl alcohol. Waxy substance used as a thickening agent and emollient in cosmetics.

arachidyl propionate. Waxy substance used as a thickening agent and emollient in cosmetics.

Arachis hypogaea extract. Extract of the plant commonly known as the peanut. It can have emollient and anti-inflammatory properties for skin, although peanut allergy is one of the five most frequent food allergies in children and adults (Source: Allergy, 2002, volume 57, Supplemental 72, pages 88–93).

arbutin. Hydroquinone derivative isolated from the leaves of the bearberry shrub, cranberry, blueberry, some mushrooms, and most types of pears. Because of arbutin’s hydroquinone content, it can have melanin-inhibiting properties. Although the research describing arbutin’s effectiveness is persuasive (even though most of the research has been performed on animals or in vitro), concentration protocols have not been established. That means we just don’t know how much arbutin it takes to have an effect in lightening the skin. Many cosmetics companies use plant extracts that contain arbutin, such as bearberry and mulberry leaf extract, but again, there is limited research, mostly animal studies or in vitro, showing that the arbutin-containing plant extracts used in skin-care products have any impact on skin. Whether or not these extracts are effective in the small amounts present in cosmetics has not been established (Sources: Phytotherapy Research, July 2004, pages 475–479; Biological & Pharmaceutical Bulletin, April 2004, pages 510–524; Clinical and Experimental Dermatology, September 2002, pages 513–515; Analytical Biochemistry, June 2002, pages 260–268, and June 1999, pages 207–219; Pigment Cell Research, August 1998, pages 206–212; and Journal of Pharmacology and Experimental Therapeutics, February 1996, pages 765–769). See hydroquinone.

Arctium lappa. See burdock root.

Arctostaphylos uva ursi leaf. See bearberry.

arginine. Amino acid that has antioxidant properties and can be helpful for wound healing (Sources: Journal of Surgical Research, June 2002, pages 35–42; Nitric Oxide, May 2002, pages 313–318; and European Surgical Research, January–April 2002, pages 53–60). See amino acid.

Argireline. See acetyl hexapeptide-3.

arnica extract. Extract from the plant Arnica montana. There is research showing that when arnica is taken orally before surgery it reduces inflammation and reduces bruising (Source: Archives of Facial and Plastic Surgery, January–February 2006, pages 54–59). However, it is repeatedly stated in all herbal journals used for the compilation of this dictionary that arnica should not be applied to abraded skin because it is a significant skin irritant. The PDR Family Guide to Natural Medicines & Healing Therapies says: “Repeated contact with cosmetics containing arnica can cause itching, blisters, ulcers, and dead skin.” (Other Sources: IFA—International Federation of Aromatherapists; and www.int-fed-aromatherapy.co.uk). Arnica also is associated with a high incidence of skin sensitization (Source: American Journal of Contact Dermatitis, June 1996, pages 94–99).

arrowroot. Thickening agent; it has no known benefit for skin.

artemia extract. See algae.

Artemisia absinthium extract. See mugwort extract.

Artemisia vulgaris. See mugwort extract.

Ascophyllum nodosum. Species of seaweed. See algae.

ascorbic acid. Form of vitamin C that has antioxidant properties (Sources: Advances in Experimental Medicine and Biology, 2002, number 505, pages 113–122; and Journal of Investigative Dermatology, February 2002, pages 372–379) and anticancer properties when taken orally (Source: Cancer Detection and Prevention, 2000, volume 24, number 6, pages 508–523). Ascorbic acid is difficult to stabilize in formulations (Source: International Journal of Pharmaceutics, October 1999, pages 233–241). Its acid component is a skin irritant.

ascorbyl glucosamine. Form of vitamin C that has little research showing it has the antioxidant or skin-lightening properties of other forms of vitamin C, although one study did show it to be ineffective for skin lightening (Source: Dermatology, 2002, volume 204, number 4, pages 281–286).

ascorbyl glucoside. Form of vitamin C combined with glucose. It can function as an antioxidant, but only minimal research substantiates this. The research that does exist combined ascorbyl glucoside with niacinamide (Source: Skin Research and Technology, May 2006, pages 105–113). It is possible the benefit resulted from only the niacinamide, and not the combination.

ascorbyl methylsilanol pectinate. Form of vitamin C that is considered stable and that functions as an antioxidant and thickening agent. See vitamin C.

ascorbyl palmitate. Stable and nonacidic form of vitamin C that is effective as an antioxidant (Source: Biochemical and Biophysical Research Communications, September 1999, pages 661–665).

asparagine. See amino acid.

Asparagopsis armata extract. Extract derived from seaweed. See algae.

aspartic acid. See amino acid.

astaxanthin. See astaxanthin extract.

astaxanthin extract. Carotenoid (carotene pigment) found in plants, algae, and fish, particularly salmon, that functions as a potent antioxidant (Source: General Physiology and Biophysics, June 2007, pages 97-103; and International Journal for Vitamin and Nutrition Research, 1995, volume 65, issue 2, pages 79–86). Preliminary research suggests that astaxanthin may be able to prevent the oxidative damage to skin after exposure to UVA radiation (Source: www.naturaldatabase.com). See antioxidant.

Astragalus membranaceus. Latin name for the Chinese herb Huang-Qi, also known as milk vetch. See milk vetch root.

Astragalus sinicus. See milk vetch root.

ATP. See adenosine triphosphate.

Atractyloydes lancea root extract. Also known as Chinese Thistle Daisy, this root extract is used in Chinese and Japanese alternative medicine for angiogenesis (the formation of new blood vessels) in type-2 diabetes because it contains beta-eudesmol. Some of its other components have been shown to have anti-inflammatory properties as well. Whether or not this can be of benefit when the entire extract is applied topically is unknown (Sources: Yajugaku Zasshi, The Pharmaceutical Society of Japan, March 2006, pages 133–143; European Journal of Pharmacology, April 2005, pages 105–115; and Planta Medica, July 2001, pages 437–442).

Avena sativa. Oat plant. Oat extract can have anti-irritant and anti-inflammatory properties (Source: Skin Pharmacology and Applied Skin Physiology, March–April 2002, pages 120–124).

avobenzone. Synthetic sunscreen ingredient (also known as Parsol 1789 and butyl methoxydibenzoylmethane) that can protect against the entire range of the sun’s UVA rays (Sources: Photodermatology, Photoimmunology, and Photomedicine, August 2000, pages 147–155; and International Journal of Pharmaceutics, June 2002, pages 85–94). See UVA.

avocado oil. Emollient oil similar to other nonfragrant plant oils. It has antioxidant properties. See natural moisturizing factor (NMF).

awapuhi. English name for wild ginger. See ginger extract.

Azadirachta indica. See neem extract.

azelaic acid. Trade name Azelex and available by prescription; a component of grains such as wheat, rye, and barley. It is effective for a number of skin conditions when applied topically in a cream formulation at 15% and 20% concentrations. In 2002 the FDA approved azelaic acid for the treatment of acne.

For the most part, azelaic acid is recommended as an option for acne treatment (Source: International Journal of Dermatology, May 2007, pages 533–538), but there is also some research showing it to be effective for treatment of skin discolorations. For example, “The efficacy of 20% azelaic acid cream and 4% hydroquinone cream, both used in conjunction with a broad-spectrum sunscreen, against melasma was investigated in a 24-week, double-blind study with 329 women. Over the treatment period the azelaic acid cream yielded 65% good or excellent results.... Severe side effects such as allergic sensitization or exogenous ochronosis were not observed with azelaic acid” (Source: International Journal of Dermatology, December 1991, pages 893–895). However, other research suggests that azelaic acid is more irritating than hydroquinone mixed with glycolic acid or kojic acid (Source: eMedicine Journal, www.emedicine.com, November 5, 2001). If you have had problems using hydroquinone along with tretinoin for skin lightening, then azelaic acid may be a consideration. See hydroquinone, tretinoin.

Azelex. See azelaic acid.

azuki beans. Legumes that are often ground up for use in skin-care scrub products.

azulene. Chamomile extract used primarily as a coloring agent in cosmetics. It can have antioxidant and anti-inflammatory properties (Sources: Journal of the European Academy of Dermatology and Venereology, September 2001, pages 486–487; and Biochemical and Biophysical Research Communications, 1996, volume 92, number 3, pages 361–364). However, there is research showing that azulene can cause cellular mutation when exposed to UVA light so it best to not use this in leave-on products (Source: Mutation Research, September 2003, pages 19–26). See chamomile.