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Written by: Sarah Morrisroe
Written on: September 1st, 2005
Tags: chemical engineering, lifestyle
Thumbnail by: Library of Congress/Wikimedia Commons
About the Author
Sarah Morrisroe graduated from the University of Southern California in May 2005, with a B.S. in Civil Engineering.
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Volume VII Issue II > Shampoo Formulation: Perception and Reality
Billions of dollars are spent by consumers on hair care products every year, mostly on shampoo. Consumers are bombarded every day by advertising that promises stronger, shinier, healthier hair. Actually, differentiating additives, such as vitamins, account for small percentages of shampoo ingredients. The consumer may be shocked to hear that many advertised promises fall flat on the basis of science.

Introduction

Hair is an accessory that we all must wear everyday, on good days and on bad days. Appearance counts and studies have consistently shown that people feel more confident when they perceive their appearance is at its best. Knowing that beauty sells and money can be made, the hair care industry bombards us day in and day out with advertisements promising shinier, stronger, and volumized hair. The supermarket confronts consumers with hundreds of products. In 2002, consumers spent $1.3 billion on shampoos alone [1]. Shampoo manufacturers are trying to grab a share of the market by making their products unique: by promising the added benefit of vitamins or herbal extracts, companies lure consumers to specific products. A question the consumer should ask before shelling out ten dollars at the pharmacy for a shampoo is how many of these promises really make a difference and what effect do they have on hair?

Human Hair

Before examining the chemistry behind shampoos, some background information on the structure of human hair is necessary. The human hair consists of two main parts: the bulb, found underneath the skin and containing the root, and the shaft, which is above the skin surface and itself consists of many parts. The shaft has several concentric layers, starting from the medulla in the center, surrounded by the cortex, and finally the outer cuticle, made of keratin [2].
Since hair is made of dead cells that are no longer splitting, damage done cannot be repaired, only covered up. The cuticle, the scaly outer layer that protects the cortex, is extremely fragile and must be dealt with carefully. The cuticle can be thought of as stacked Styrofoam cups. When damaged or prone to damage, those cups will open out like a Christmas tree and can break off. Nowadays, companies formulate shampoo to minimize cuticle damage.