Which condition should a stylist avoid when working with alkaline treatments?

When working with alkaline treatments, a stylist should avoid using them on weak hair. Alkaline formulations raise the pH level of the hair, which can open the cuticle and allow for deeper penetration of chemicals. While this can be effective for certain treatments, weak hair is already vulnerable due to damage or excessive processing. Applying alkaline treatments can further compromise the integrity of weak hair, leading to more breakage, split ends, and other damage.

In contrast, curly hair, thick hair, and color-treated hair can be managed with proper techniques, and with more robust formulations, these types of hair can often handle alkaline treatments without suffering as severe a negative reaction as weak hair would. Thus, understanding the condition of the hair is crucial when selecting appropriate treatments.