The use of cosmetics is not a thing of the future. In fact, cosmetics were founded in Ancient Egyptian time. It was said that Ancient Egyptian women used kohl to darken their eyelids, and Cleopatra said to have bathed in milk to whiten and soften her skin. Not only that, Greek women used poisonous lead carbonate to achieve a pale looking complexion, and in the end claiming the life of the wearer due to its poisonous state. Today, cosmetics are big business. Cosmetic advertising are everywhere, attracting males and females who seriously cares about appearances.
What is a cosmetic? Cosmetic is defined as a substance or preparation intended for placemtn in contact with any external part of the human body. Cosmetics are used to cleanse, perfume, protect and change the appearance of the body or to alter its odours. Products that claim to modify bodily process or prevent diagnose, cure or alleviate any disease, ailment or defects are called therapeutics. This means that shampoos and deodorants are placed in the cosmetics category, while anti-dandruff shampoos and antiperspirants are considered therapeutics.
What do cosmetics contain? Most cosmetics contain water, emulsifier, preservative, thickener, colour, fragrance and pH stabilisers. For emulsifiers, emulsifiers are small droplets of oil dispersed in water or small droplets of water dispersed in oil.
Emulsifiers work by changing the surface tension between water and the oil, thus producing a homogeneous product with an even texture. As for preservatives, preservatives are added to prevent the growth of microoganisms, which can spoil the product and most probably harm the user. Preservatives used in cosmetics include parabens, benzyl alcohol and tetrasodium EDTA( ethylenediaminetetra-acetic acid).
Thickening agents such as polymers are often added to change the cosmetics consistency. Polymers can be synthetic (polyetylene glycol) or derived from natural sources (polysaccharides). Seaweed are common source of polysaccharides. Cosmetics that are too thick can be diluted with solvents such as water or alcohol.
Unfortunately, sometimes the ingredients in cosmetics can have unintended side-effects. For example, skin allergies to specific ingredients can be a problem. Allergies to cosmetic products can be due to chemicals such as added fragrances and preservatives. This can lead to skin rash where the product is applied. Chemicals causing the allergy can be avoided by reading product labels. Other people, which is not allergic to a specific ingredient, may nevertheless find the product irritates their skin becuase it damages the otuer layers, knwon as irritant dermatitis
Exfoliants and skin peels leave skin underneath temporarily more vulnerable to sun exprosure because they remove the outermost protective layer of dead skin cells. Excessive use of make-up or oily moisturiser can block pores and aggravate acne. More serious side effects are breast cancer with deodorants. Parabens, a class of chemicals commonly used as preservatives in deodorants and antiperspirants.
In the pursuit of beauty, there lies side effects. Therefore, it is wise to remember that cosmetics can be complex combinations of chemicals. Reading and understanding which ingredients are used in product are helpful when putting on cosmetics.
Referrence links,
http://www.science.org.au/nova/083/083key.htm
http://en.wikipedia.org/wiki/Cosmetics
http://www.badscience.net/category/cosmetics/
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