Final answer:
Chemically treated hair is hair that has undergone alteration using chemical products or processes such as coloring, perming, straightening, and chemical depilation. These treatments change the hair's structure and may have long-lasting effects. Specialty hair care products are often used to mitigate damage from these treatments.
Step-by-step explanation:
Chemically treated hair refers to hair that has been altered through the use of chemical products or processes. This can include permanent or semi-permanent hair coloring, where natural pigments are removed and synthetic colors are added. Chemical straightening or relaxing, and perms, which reshape the hair by breaking the natural bonds and reforming them, also fall under this category. These treatments alter the hair's structure and can have a lasting effect until the hair grows out or is cut.
Another form of chemical treatment is the use of chemical depilatories, such as creams or gels that contain active ingredients like calcium thioglycolate, to remove hair from the skin. These preparations break down the hair's keratin by affecting the disulfide bonds, allowing for easy hair removal without affecting the dermal papilla, meaning the hair will grow back.
Additionally, hair can be bleached using diluted hydrogen peroxide mixed with aqueous ammonia, leading to a lighter hair shade. This chemical process is termed as "peroxide blonde" due to the common use of hydrogen peroxide. It is important to note that recurring chemical treatments can cause damage to the hair, which is why individuals with chemically treated hair often use specialty shampoos or conditioners formulated to minimize potential harm and nourish the hair.