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ARTICLES IN THE BOOK

  1. Academy Award for Makeup
  2. Aloe
  3. Alpha hydroxy acid
  4. Anti-aging cream
  5. Arenation
  6. Aromatherapy
  7. Artistry
  8. Astringent
  9. Beauty
  10. Beauty mark
  11. Beauty salon
  12. Camouflage Cosmetic
  13. Campaign for Safe Cosmetics
  14. Carnauba wax
  15. Castor oil
  16. Chanel No. 5
  17. Chemical peel
  18. Christian Dior
  19. Clinique
  20. Concealer
  21. Corpse paint
  22. Cosmeceutical
  23. Cosmetic advertising
  24. Cosmetics
  25. Cosmetology
  26. Creed
  27. Dermabrasion
  28. Dermatology
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  30. Eau de cologne
  31. Electrology
  32. Elizabeth Arden
  33. Essential oil
  34. Estée Lauder
  35. Estée Lauder Companies
  36. Estée Lauder pleasures
  37. Exfoliation
  38. Eye liner
  39. Eyeshadow
  40. Facial toning
  41. Glitter
  42. Glycerol
  43. Guerlain
  44. Hair
  45. Hair extension
  46. Helena Rubinstein
  47. Hermès
  48. History of cosmetics
  49. History of Perfume
  50. Hot tub
  51. INCI
  52. Jojoba oil
  53. Kohl
  54. Lancome
  55. Lip gloss
  56. Lip plumper
  57. Lipstick
  58. List of cosmetic ingredients
  59. L'Oréal
  60. Makeover
  61. Make-up artist
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  101. What Not to Wear

 

 



COSMETICS
This article is from:
http://en.wikipedia.org/wiki/Skin_whitening

All text is available under the terms of the GNU Free Documentation License: http://en.wikipedia.org/wiki/Wikipedia:Text_of_the_GNU_Free_Documentation_License 

Skin whitening

From Wikipedia, the free encyclopedia

 

Skin whitening is a term covering a variety of cosmetic methods used to whiten the skin. It is especially popular in Eastern Asian countries, but is also used in parts of Latin America, Southern Africa, Mauritius and the United States.

Uses

Specific zones of abnormally high pigmentation such as moles and birthmarks may be depigmented to match to the surrounding skin. Conversely, in cases of vitiligo, unaffected skin may be lightened to achieve a more uniform appearance.

Some people treat larger areas to lighten the natural complexion, out of esthetic preference or to avoid social/work discrimination and gain access to better income (this is true, for example, of prostitutes) or higher social position. [1]

An additional applicacion is genital or anal bleaching, intended to reduce the typically darker pigmentation of the genital and perianal area.

History

In eastern Asian countries, pale skin represented royalty or sophistication. Most royals were believed to have their pale skin from staying indoors all day as opposed to the farmers who spent their lives working in rice paddy fields under the sun.

In Japan, geishas were (and still are) known for their painted white skin, which represents beauty, grace, and high social status.

In Iran, during the Achaemenid dynasty, farmers and civil workers used some kind of lightening lotion to keep their skin white and soft.

In parts of Latin America and Africa, white skin is appreciated and associated with higher social status along with light-colored, straight hair (see Colonial mentality), and depigmentation may be used as a permanent alternative to makeup.

Today, skin whitening products are available in the form of creams, pills, soaps or lotions. The mechanism of permanent whitening is usually by the breakdown of melanin by enzymes, such as that contained in the droppings of the Japanese bush warbler or reducing agents such as Hydroquinone. Most whitening creams also contain a UV block to prevent sun damage to the skin.

Further information: History of cosmetics

Melanin and pigmentation

Uneven pigmentation afflicts most people, regardless of ethnic background or skin color. Skin may either appear lighter or darker than normal; there may be blotchy, uneven areas, patches of brown to gray discoloration or freckling. Skin pigmentation disorders occur because the body produces either too much or too little melanin. Melanin is the pigment produced by melanocyte cells. It is triggered by an enzyme called tyrosinase, which creates the color of skin, eyes, and hair shades.

Melanin has two major forms that combine to create varying skin tones. Eumelanin produces a range of brown skin and hair color, while pheomelanin imparts a yellow to reddish hue.

Melanin provides some amount of sun protection for the skin by absorbing ultraviolet light. Darker skin colors are less susceptible to sunburn and the overall effects of sun damage.

Increased melanin production — also known as hyperpigmentation — is often referred to as melasma, chloasma or solar lentigenes.

  • Melasma is a general term describing darkening of the skin.
  • Chloasma is generally used to describe skin discolorations caused by hormones. These hormonal changes are usually the result of pregnancy, birth control pills or estrogen replacement therapy.
  • Solar lentigenes is the technical term for darkened spots on the skin caused by the sun. Solar refers to sunlight and lentigene describes a darkened area of skin. These spots are quite common in adults with a long history of unprotected sun exposure.

Aside from sun exposure and hormones, hyperpigmentation can be caused by skin damage, such as remnants of blemishes, wounds or rashes.[2] This is especially true for those with darker skin tones.

The most typical cause of darkened areas of skin, brown spots or areas of discoloration is unprotected sun exposure. Once incorrectly referred to as liver spots, these pigment problems are not connected with the liver.

On lighter to medium skin tones, solar lentigenes emerge as small- to medium-sized brown patches of freckling that can grow and accumulate over time on areas of the body that receive the most unprotected sun exposure, such as the back of the hands, forearms, chest, and face. For those with darker skin colors, these discolorations can appear as patches or areas of ashen-gray skin.

Combination treatments

Most skin-lightening treatments, which can reduce or block some amount of melanin production, are aimed at inhibiting tyrosinase. Many treatments use a combination of topical lotions or gels containing melanin-inhibiting ingredients along with a sunscreen, and a prescription retinoid. Depending on how the skin responds to these treatments, exfoliants — either in the form of topical cosmetic or chemical peels — and lasers may be used. [3]

Sunscreen

Sunscreen is a product used to protect the skin from ultraviolet rays, to avoid damage and/or darkening of the skin. Higher SPFs contain greater quantities of the UVA-protecting ingredients titanium dioxide, zinc oxide or avobenzone.[4]

Topical treatments

Topical hydroquinone is considered by many dermatologists to be a safer, similarly effective (if not more so), and less expensive option than lasers or deep peel treatments. Topical hydroquinone comes in 2% (available in cosmetics) to 4% concentrations (available from a physician or by prescription), alone or in combination with tretinoin 0.05% to 0.1%. Research has shown hydroquinone and tretinoin to be powerful tools against sun- or hormone-induced melasma.[5]

Some research has shown topical azelaic acid in 15% to 20% concentrations to be as efficacious as hydroquinone with a decreased risk of irritation. Tretinoin by itself has also been shown to be useful in treating hyperpigmentation of sun-damaged skin. Kojic acid, alone or in combination with glycolic acid or hydroquinone, also has shown good results due to its inhibitory action on tyrosinase (though kojic acid has had problems in terms of stability and potential negative effects on the skin and is rarely used today). Several plant extracts and vitamin C also have some research showing them to be effective for inhibiting melanin production. [6]

Hydroquinone

In medical literature, hydroquinone is considered the primary topical ingredient for inhibiting melanin production.[7] Its components have potent antioxidant abilities.[8]

Hydroquinone is a strong inhibitor of melanin production, meaning that it prevents skin from making the substance responsible for skin color.[9] Hydroquinone does not bleach the skin, and can only disrupt the synthesis and production of melanin hyperpigmentation.

Some concerns about hydroquinone's safety on skin have been expressed, but the research when it comes to topical application indicates negative reactions are minor or a result of using extremely high concentrations or from other skin-lightening agents such as glucocorticoids or mercury iodine. This is particularly true in Africa where adulterated skin lightening products are commonplace.[10]

Because of hydroquinone's action on the skin, it can be irritant, particularly in higher concentrations of 4% or greater and predictably when combined with tretinoin. Some medications have been created that combine 4% hydroquinone with tretinoin and a form of cortisone. The cortisone is included as an anti-inflammatory. The negative side effect of repeated application of cortisone is countered by the positive effect of the tretinoin so that it does not cause thinning of skin and damage to collagen.[11]

Hydroquinone can be an unstable ingredient in cosmetic formulations. When exposed to air or sunlight it can turn a strange shade of brown. Therefore, when you are considering a hydroquinone product, it must be packaged in a non-transparent container that minimizes light and air exposure. Hydroquinone products packaged in jars are not recommended because they become ineffective shortly after opening.

Alternatives to hydroquinone

Some of alternative lighteners are derivatives of hydroquinone. They include Mitracarpus scaber extract, Uva ursi (bearberry) extract, Morus bombycis (mulberry), Morus alba (white mulberry), and Broussonetia papyrifera (paper mulberry). All of these contain arbutin (technically known as hydroquinone-beta-D-glucoside), which can inhibit melanin production. Pure forms of arbutin are considered more potent for affecting skin lightening (alpha-arbutin, beta-arbutin, and deoxy-arbutin).

Other options with some amount of research regarding their potential skin lightening abilities are licorice extract (specifically glabridin), azelaic acid, and stabilized vitamin C (L-ascobic acid, ascorbic acid, and magnesium ascorbyl phosphate).

There is also a small amount of research showing oral supplements of pomegranate extract, ellagic acid, vitamin E, and ferulic acid can inhibit melanin production.[12]

Arbutin

Arbutin contains a form of hydroquinone derived from the leaves of bearberry, cranberry, mulberry or blueberry shrubs, and also is present in most types of pears. Because of arbutin's hydroquinone content it can have melanin-inhibiting properties.[13] Concentration protocols have yet to be established for arbutin, meaning it is not known how much arbutin it takes to lighten skin when it is added to a cosmetic formulation. Moreover, there are patents controlling its use for skin lightening. Many cosmetics companies use plant extracts that contain arbutin. There is little to no research showing the plant extract source of arbutin as having any impact on skin, especially not in the tiny amounts used in cosmetics.[citation needed]

Tretinoin

Research has shown that the use of tretinoin (also known as all-trans retinoic acid) can only be somewhat effective in treating skin discolorations.[14]

Tretinoin also has a role in the improvement of skin's healthy cell production, collagen production, elasticity, texture, and dermal thickness.

Alpha hydroxy acids

Alpha hydroxy acids (AHAs) — primarily in the form of lactic acid and glycolic acid — are the most researched forms of AHAs because they have a molecular size that allows effective penetration into the top layers of skin. It is generally assumed that in and of themselves AHAs in concentrations of 4% to 15% are not effective for inhibiting melanin production and will not lighten skin discolorations in that manner. It is believed that their benefit is in helping cell turnover rates and removing unhealthy or abnormal layers of superficial skin cells (exfoliation) where hyperpigmented cells can accumulate. However, other research has shown that lactic and glycolic acids can indeed inhibit melanin production separate from their actions as an exfoliant on skin. [15]

Like laser treatments, alpha hydroxy acid peels (using 50% concentrations or greater) may remove skin discolorations. Only a qualified physician should perform these types of facial peels.[16]

Kojic acid

Kojic acid is a by-product in the fermentation process of malting rice for use in the manufacturing of sake, the Japanese rice wine. Some research shows kojic acid to be effective for inhibiting melanin production.[17] However, kojic acid is an unstable ingredient in cosmetic formulations. Upon exposure to air or sunlight it can turn brown and lose its efficacy. Many cosmetic companies use kojic dipalmitate as an alternative because it is more stable in formulations. However, there is no research showing kojic dipalmitate to be as effective as kojic acid, although is it a good antioxidant. Further, some controversial research has suggested that kojic acid may have carcinogenic properties.[18]

Azelaic acid

Azelaic acid is a component of grains, such as wheat, rye, and barley. It is applied topically in a cream formulation at a 20% concentration. Azelaic acid is used to treat acne, but there also is research showing it to be effective for skin discolorations.[19] Other research also indicates azelaic acid may be an option for inhibiting melanin production.[20]

Vitamin C

Magnesium ascorbyl phosphate, L-glutothione, L-ascorbic acid, ascorbyl glucosamine, and ascorbic acid are various forms of vitamin C considered stable and effective antioxidants for skin. There are very few studies showing them to have benefit for inhibiting melanin production. The concentrations of these ingredients used in tests were generally high (more than 5%), which is rarely used in cosmetic formulations.[21]

Laser treatments

Both ablative and nonablative lasers can have a profound effect on melasma. However, the results are not always consistent, and problems have been reported (such as hypo- or hyperpigmentation). Laser treatments of this kind are more likely to result in problems for those with darker skin tones.[22]

References

  1. ^ http://www.ecpat.net/eng/ecpat_inter/Publication/Other/English/Pdf_page/ecpat_sex_tourism_dom_rebublic.pdf
  2. ^ Cutis, August 2005, pp 19-23
  3. ^ Journal of the American Academy of Dermatology, May 2006, supplemental, pages 272-281; Dermatologic Surgery, March 2006, pages 365-371; Journal of Drugs in Dermatology, September-October 2004, supplemental, 27-34; International Journal of Dermatology, December 2003, pages 966-972; and Archives of Dermatology, December 2002, pages 1578-1582).
  4. ^ Journal of the American Academy of Dermatology, May 2005, pages 786-792; American Journal of Epidemiology, April 2005, pages 620-627; and The British Journal of Dermatology, December 1996, pages 867-875.
  5. ^ Dermatologic Surgery, March 2006, pages 365-371.
  6. ^ Journal of the American Academy of Dermatology, May 2006, pages S272-S281; International Journal of Dermatology, August 2004, pages 604-607; and The American Journal of Clinical Dermatology, September-October 2000, pages 261-268).
  7. ^ Cutis, March 2006, pages 177-184; Journal of Drugs in Dermatology, September-October 2005, pages 592-597; Journal of Cosmetic Science, May-June 1998, pages 208-290; Dermatological Surgery, May 1996, pages 443-447.
  8. ^ Journal of Natural Products, November 2002, pages 1605-1611.
  9. ^ Journal of Dermatological Science, August, 2001, supplemental, pages 68-75.
  10. ^ British Journal of Dermatology, March 2003, pages 493-500 and Critical Reviews in Toxicology, May 1999, pages 283-330.
  11. ^ Drugs in Dermatology, July-August 2004, pages 377-381.
  12. ^ Experimental Dermatology, August 2005, pages 601-608; Bioscience, Biotechnology, and Biochemistry, December 2005, pages 2368-2373; International Journal of Dermatology, August 2004, pages 604-607; Journal of Drugs in Dermatology, July-August 2004, pages 377-381; acial and Plastic Surgery, February 2004, pages 3-9; Dermatologic Surgery, March 2004, pages 385-388; Journal of Bioscience and Bioengineering, March 2005, pages 272-276; Journal of Biological Chemistry, November 7, 2003, pages 44320-44325; Journal of Agriculture and Food Chemistry, February 2003, pages 1201-1207; International Journal of Cosmetic Science, August 2000, pages 291-303; and Anti-Cancer Research, September-October 1999, pages 3769-3774).
  13. ^ The Journal of Pharmacology and Experimental Therapeutics, February 1996, pages 765-769.
  14. ^ Dermatologic Surgery, March 2006, pages 365-371; Acta Dermato-Venereologica, July 1999, pages 305-310; International Journal of Dermatology, April 1998, pages 286-292; and Journal of the American Academy of Dermatology, March 1997, pages S27-S36.
  15. ^ Experimental Dermatology, January 2003, supplemental. pages 43-50.
  16. ^ Dermatologic Surgery, February 2005, pages 149-154; Journal of Cutaneous Medicine and Surgery, April 2004, pages 97-102; Cutis, February 2004, supplemental, pages 18-24; Dermatologic Therapy, June 2004, pages 196-205; and Dermatological Surgery, June 1999, pages 450-454.
  17. ^ Archives of Pharmacal Research, August 2001, pages 307-311.
  18. ^ Mutation Research, Genetic Toxicology and Environmental Mutagenesis, June 2005, pages 133-1450 and Toxicological Sciences, September 2004, pages 43-49.
  19. ^ International Journal of Dermatology, December 1991, pages 893-895.
  20. ^ Journal of the American Academy of Dermatology, May 2006, supplemental, pages 272-281.
  21. ^ International Journal of Dermatology, August 2004, page 604; Dermatology, April 2003, pages 316-320; Journal of the American Academy of Dermatology, January 1996, pages 29-33.
  22. ^ Journal of the American Academy of Dermatology, May 2006, supplemental, pages 262-271; Dermatologic Therapy, January 2001, page 46; Journal of Cosmetic and Laser Therapy, March 2005, pages 39-43; Journal of Cutaneous Medicine and Surgery, April 2004, pages 97-102; Journal of Drugs in Dermatology, November-December 2005, pages 770-774; Dermatologic Surgery, October 2005, page 1263; and Lasers in Surgery and Medicine, April 2000, pages 376-379.

See also

  • Colonial mentality
  • Sun tanning
  • Black pride
  • Hydroquinone
  • History of cosmetics
Retrieved from "http://en.wikipedia.org/wiki/Skin_whitening"

 



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