Which of the following relaxer strengths for ammonium thioglycolate is NOT categorized?

Ammonium thioglycolate relaxers are typically categorized based on their strength and intended use on different hair types. The correct choice reflects that there is no standard category termed "Heavy" for the strengths of ammonium thioglycolate relaxers.

Relaxers are generally classified into categories such as Regular, Super, and Mild. Regular strength is suitable for normal, resistant hair; Super is formulated for very coarse or resistant hair, and Mild is intended for color-treated or damaged hair. Each classification serves to ensure that the appropriate product is used to avoid damaging the hair while achieving the desired level of straightening.

On the other hand, "Heavy" does not correspond to any established category in the context of ammonium thioglycolate relaxers. This term is not recognized as a standard strength classification in the industry, which makes it the correct answer to identify as not categorized within the known classifications. Understanding these nuances helps hairstylists choose the appropriate products for their clients based on their hair texture and condition.