What are the two main types of relaxers used in hair treatment?

The two main types of relaxers used in hair treatment are sodium hydroxide and ammonium thioglycolate. Sodium hydroxide relaxers, often referred to as "lye relaxers," work by breaking the disulfide bonds in the hair, allowing it to be reshaped into a straighter style. They are known for their strength and effectiveness, particularly in very curly or coarse hair types.

Ammonium thioglycolate relaxers, on the other hand, are considered "no-lye relaxers" and are less harsh on the hair compared to sodium hydroxide. They also break disulfide bonds but do so in a manner that is gentler on the hair and scalp. Ammonium thioglycolate products can be suitable for different hair types and may also be used in a variety of chemical services, including perms.

Understanding these two types of relaxers is essential for cosmetologists, as it allows them to choose the most appropriate products based on the client's hair type and desired results. The other options do not correctly identify the main types of relaxers used in the industry.