• Núria Estapé, science journalist

    Skin bleaching: when skin has to be white

    The whimsical dictates of fashion have led to the proliferation of creams and other cosmetics to bleach dark skin, as people who use these products believe that lighter skin is more attractive. Are such products effective? Can skin be bleached safely?

     

    The law of the pendulum dictates that fashions swing between extremes, in this case, from the magnetism of tanned skin to the purity of alabaster skin. Controversy has recently arisen in countries like India, where advertisements encouraginge women to use skin bleaching products convey negative messages of social rejection for women with dark complexions.

     

    Blocking melanin production

    Most substances that whiten the skin, such as hydroquinone, act by preventing the skin from producing melanin, the pigment responsible for skin tone. Melanin is manufactured in cells called melanocytes, found in the basal layer located between the epidermis and the dermis. Each melanocyte is surrounded by about 36 keratinocytes (keratin-manufacturing cells). Melanin is produced inside the vesicles (tiny bags) contained within the melanocytes. The manufactured pigment diffuses through the keratinocytes and carries out its function in the skin fibres.

    Skin-whitening substances act in different ways during melanin manufacture and transport process. This pigment is formed with the aid of an enzyme called tyrosinase, located in the membrane of melanocytes. Hydroquinone acts by blocking this enzyme so melanin cannot be manufactured.

    Despite its proven efficacy as a bleach, hydroquinone was withdrawn from the cosmetic market in Europe and Japan in 2000 as toxic for melanocytes and the liver and now is only sold in pharmacies .

     

    The reign of white skin

    Hydroquinone is still used without any control in some countries. Social pressure to have light-coloured skin leads many women, even today, to ignore the long-term side effects. Applied over a long period, hydroquinone may react with ultraviolet rays and produce a rebound effect in which the skin begins to oxidize again and produce excess pigmentation. In addition, the skin becomes irritated and prematurely ages, due to thickening collagen fibres, and this, in turn, damages the connective tissue.

    Recently, Leila Lopez, the Angolan Miss Universe, caused controversy as a consequence of the fact that she apparently bleached her skin. For this black beauty queen and the late Michael Jackson, bleached skin could not fail to be noticed.

     

    Natural, safe bleaches

    Fortunately, skin can be safely bleached, whether using a household remedy or cutting-edge science. Products to be found on the market nowadays are derived from various natural substances and act in different ways. Typical components of cosmetic bleaching creams are as follows:

     

    1 - Arbutin (deoxyarbutin) is a hydroquinone derivative which is found in fruits such as pears and blackberries that acts in the same way as hydroquinone but is not so toxic for the skin cells.

     

    2 - Kojic acid, which has bleaching and anti-oxidant properties, is extracted from the fungus Aspergillus oryzae and azelaic acid is obtained naturally from wheat, rye and certain yeasts. Both acids are indicated to treat acne, rosacea and skin hyperpigmentation problems such as melasma, although kojic acid is particularly effective in treating moles and age spots.

     

    3 - Phytic acid, mostly found in the seeds of cereals and in nuts, is an antioxidant that blocks the entry of iron and copper in the melanin formation process.

     

    4 - Aloesin, also an anti-oxidant and anti-inflammatory agent, is obtained from Mediterranean plants like Aloe vera.

     

    5 - Niacinamide, the active form of niacin (vitamin B3), is found in plant roots and yeast. It blocks transportation of the melanosomes (the tiny bags where melanin is stored) to the keratinocytes.

     

    6 - The alpha-hydroxy acids – glycolic acid, retinoic acid, ascorbic acid (vitamin C), linoleic acid and glycyrrhizic acid (extracted from licorice) – accelerate renewal of the epidermis and enhance the depigmentation action of other components. Lactic acid, meanwhile, exfoliates and hydrates the skin and activates ceramides so as to create a fatty-acid-based protective barrier.

     

    Many bleaching products currently available in the market also contain sunscreens and plant extracts (Ferula foetida and Phyla nodiflora) that also block melanin production.

    If you are thinking about using a skin bleach, whether for aesthetic reasons or for a pigmentation disorder, you should ensure that you are first informed of the safety of the product. And above all, make sure it contains a sunscreen and that none of its components irritate the skin or sensitize it to sunlight.

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