Relaxing And Straightening Of Afro-Ethnic Hair: Historical Overview

The document provided a historical overview of the methods used to relax or straighten Afro-ethnic hair, highlighting the unique characteristics of this hair type, such as variations in diameter, ellipsoidal threads, and irregular sebum distribution leading to dryness. It discussed both chemical and thermal methods for straightening, with a focus on the chemical process that irreversibly straightens excessively curly hair using high pH cosmetic emulsions. The review traced the evolution of product categories used for hair straightening over time.