Perceptions in Cleaning Hair and the Subjective Testing of Shampoos

Breuer [13] has described the kinetics for reoiling of hair in terms of sebum production and sebum removal. He derived the following expression to describe the rate of reoiling  

Perceptions in Cleaning Hair and the Subjective Testing of Shampoos 

With the advent of two-in-one shampoos, a new era has begun in cosmetic science. Differences in the performance between different conditioning shampoos can be relatively large, and these can be detected in laboratory tests, in half-head tests, and even in consumer tests on cell sizes smaller than N = 100. To the cosmetic scientist, this is a pleasant situation. We can now turn our attention to real product performance. We can truly work to create products that are really better, not only in the laboratory but also in the marketplace. This situation was created by a combination of new technology and consumers becoming willing to accept different standards of performance for shampoos, and I believe this same situation exists for other opportunities in hair care in the future (e.g., hair body or hair thickening shampoos). 

The situation is not as clear for cleaning shampoos. However, with the new soils that we are leaving behind on hair for superior conditioning, body, and style control, perhaps new performance opportunities in hair cleaning will also become feasible in the future. 

Nevertheless, the following discussion is useful for all product types when the differences between real product performance become relatively small, 

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