How does hair bleach affect your medulla?

Hair bleach primarily affects the hair shaft, not the medulla, which is the innermost layer of the hair. The chemicals in bleach, such as hydrogen peroxide and ammonia, penetrate the hair cuticle and disrupt the structure of the cortex, leading to the lightening of hair color. While the medulla may not be directly impacted by bleach, overall hair health can be compromised, resulting in dryness, brittleness, and potential damage to the hair structure.