Journal of Cosmetic Science, 58, 629–636 (November/December 2007) Hair Breakage During Combing: Brushing and Combing Hair

The study investigated hair breakage during combing and brushing, focusing on the mechanisms of long and short segment breaks. It found that longer fiber breaks (>2.5 cm) mainly occurred due to impact loading of looped crossover hairs, while shorter breaks (<2.5 cm) were primarily due to end wrapping. Brushing resulted in a higher ratio of long-to-short segment breaks compared to combing. Factors such as bleaching, longer comb strokes, increased fiber curvature, and wet versus dry combing influenced the increase in long segment breaks, with brushing having the most significant effect. The ratio of long-to-short segment breaks (L/S) was identified as a useful measure to track these breakage pathways under various conditions.