Kansas Cosmetology Practice Exam

Formaldehyde or its derivatives are commonly found in hair straightening products due to their ability to create bonds that alter the hair’s structure, resulting in a straighter appearance. These chemicals work by breaking down the disulfide bonds in the hair, which are responsible for its natural curliness or wave. When heat is applied during the treatment, these bonds are re-formed in a straightened configuration.

Formaldehyde itself can be quite effective in these applications, but because of health concerns related to its use—such as potential respiratory issues and skin irritation—some products may utilize its derivatives. These derivatives can achieve similar results while potentially reducing health risks. This makes them a popular choice in many contemporary straightening products used in salons.

The other options, while possibly used in various hair treatments, do not serve the same primary function in straightening hair. Hydrogen peroxide is primarily an oxidizing agent used to lighten hair, ammonia is used mainly in chemical hair coloring and perming, and alpha hydroxy acids are typically used for their exfoliating properties in skin care rather than in hair straightening treatments.