Dry hair smoothness is a key preference driver for many hair products, including shampoos and conditioners.  Furthermore, restoration of dry hair smoothness is an important signal to consumers of hair damage repair.  As a result, hair friction experiments are widely used in the category for performance testing of conditioning systems, and for supporting damage repair claims.

The dry surface friction test simulates the forces required to rub one’s fingers over the surface of the hair after it has been washed and dried.  It is, therefore, designed to relate directly to the perception of hair smoothness, or, alternatively, the lack of hair dryness.  This is different to the ease-of-combing tests that assess the forces required to untangle the hair with a brush or comb.

The TRI dry surface friction test measures the force required to pull a tress of hair through two rubber cylinders pressed together to simulate the ends of your fingers.  Careful control of the speed at which the hair is pulled through, the pressure between the cylinders and the environmental conditions (room temperature and humidity), allow us to discriminate between different conditioning products and to measure damage repair effects.

Hair friction studies, like hair combing studies, are sensitive to the levels of curl and underlying hair damage and are prone to high levels of variability.  TRI can advise on the best protocols for your study.