Under what condition should a salon professional avoid using ammonium thioglycolate?

Ammonium thioglycolate is a chemical used in perm solutions and can alter the hair structure to create curls or waves. It is crucial for salon professionals to understand the interactions between different chemical treatments to avoid damaging the hair.

When hair has been treated with sodium hydroxide, which is often used in relaxers, it has undergone a significant structural change making it straight. Both ammonium thioglycolate and sodium hydroxide are strong chemicals that serve opposite purposes—where ammonium thioglycolate aims to curl hair, sodium hydroxide is intended to straighten it. Using ammonium thioglycolate on hair that has previously been chemically relaxed with sodium hydroxide can lead to unpredictable results, such as severe damage, because the hair may not respond well to another chemical process so soon after being straightened. This can lead to issues like breakage, brittleness, and overall compromised hair integrity.

Professionals should always assess the hair's chemical history and health before applying any new treatments, particularly when dealing with different types of chemical services that can interact negatively.