Understanding Breakage in Curly Hair

In 2005, the L'Oréal Institute for hair and skin research conducted a study on hair breakage among women in the U.S., finding that 96% of African-American respondents experienced breakage. The study suggested that structural differences and grooming-induced stresses, rather than chemical composition, contribute to this higher incidence. To understand the fracture mechanisms in African-American hair, hair from a volunteer was subjected to controlled mechanical stresses and analyzed using scanning electron microscopy and X-ray tomographic microscopy. The research identified a breakage mechanism involving cuticle sliding, failure at the cuticle-cortex interface, crack nucleation and growth, and final breakage due to merging cracks. The study concluded that mechanical damage and environmental factors cause internal cracks leading to breakage, recommending continuous hair care throughout the hair's life cycle.