By C. Uhl, D. Khazaka, and A. Pouladi
Hair diversity (style, shape, growth pattern or color) is one of the most important features to define us physically.
Therefore, it is no surprise that the market of hair care products with a value of 93.5 billion US $1 (Statistica, September 2020) is one of the most important sectors in the complete area of cosmetic products. Hair care products for women are the most frequently bought and used cosmetic products of all. Shampoos and conditioners are leading the field. For men, hair care is the most important and favored sector of all cosmetics.2
However, there is more to it. Nowadays, social media, most of all Instagram, influences different generations. Besides skin, hair is the characteristic attribute for health, youth and attraction. Hair can even be a communication tool and a political instrument. Just take as an example the men who grow a moustache of their own style every November of a year, the so called Movember, to raise funds for men’s health.2
Plenty of products and treatments are ready to fit the modern hair care market for thin, thick, curly, dry, oily, blonde, coloured, ethnic, young, or old hair. Imagine any claim, the product is already invented. As hair is unique, personalised products flood the hair care market. Respectively, there is an ever-growing number of claims around the various products. Hair care rituals can be complemented with food supplements and treatment devices.3
Tests on hair tresses
In this context, claim-related best practice in vitro biophysical methods, including instrumental methods (mechanical and visual) to describe hair fibre characteristics, have been established:4,5,6
The most widely used instrumental-based mechanical test to measure the efficacy of shampoos, conditioners, masks and other hair care products is the combing forces test on hair tresses as it supports a broad range of claims. Wet and dry combing forces are determined to substantiate claims such as combability, conditioning, detangling or easy-to-comb. Mechanical measurements of hair breakage provoked by continuous combing of hair tresses show how effective hair care products are regarding protection or resistance to hair damage caused by combing. The amount of broken hair fragments is determined to support claims such as anti-split ends or anti-breakage.
