Which hair type is most resistant to chemical treatments?

Coarse hair is most resistant to chemical treatments due to its structure and thickness. The cuticle layer of coarse hair typically has a more substantial barrier that makes it less susceptible to damage from chemicals. This resistance can be attributed to the larger diameter of the individual hair strands, which provides more resilience against harsh treatments such as perming, coloring, or relaxing.

In contrast, fine hair tends to be more fragile and can be more easily affected by chemical processes, resulting in potential damage or breakage. Medium hair has a balanced texture and may respond fairly well to chemical treatments, but it does not exhibit the same level of resistance as coarse hair. Curly hair, despite its unique structure, often has varying degrees of porosity and may absorb chemicals differently, making it not as universally resistant as coarse hair. Thus, coarse hair is recognized for its robustness, making it the most resistant among the hair types listed.