Effects of co-surfactant and conditioning agent on colour

The colour-fading of hair treated with oxidative dyes is attributed to the effects of ultraviolet light and other environmental factors, but mostly it occurs during shampooing. This effect is caused by the diffusion of chromaphores from within the cortex towards the cuticle surface. The colour fading of dyed hair during shampoo washing is determined by a range of factors, most significantly by the chemistry of the chromaphores, the porosity of the hair fibres, and the properties of the used surfactants. Optimising the cleansing efficacy of shampoos in relation to colour protection claims is of interest to formulators.

This study investigates the effects of two co-surfactants and a range of conditioning additives, polycationic and silicone-based, on the colour fading of hair tresses treated with red oxidative hair dye and put through repeated wash-and-dry cycles. The results indicate that the choice of co-surfactant alone, and in combination with the conditioning additives, can significantly influence the colour fading of red oxidative dye treated hair during shampooing. The amphoteric co-surfactant offered statistically significant improved colour retention, compared to the nonionic. Furthermore, the silicone based conditioning additive delivered enhanced colour retention in comparison with the selected cationic polymers.