What is a chemical service that involves applying heat to the hair for straightening?

The correct answer is associated with a chemical service known as a keratin treatment. This treatment involves applying a keratin-infused formula to the hair and then using heat to seal the product into the hair strand. The application of heat helps to restructure the hair’s natural proteins, resulting in smoother, straighter hair. These treatments are designed to reduce frizz, add shine, and improve the manageability of the hair, making them popular among individuals seeking a straighter look without the use of harsh chemicals found in traditional relaxers.

In contrast, perming involves a chemical process that curls or waves the hair through the use of rods and a perm solution, which does not involve straightening. Changing hair color focuses solely on altering the hue of the hair and does not involve heat for straightening purposes. Hair masking typically refers to treatments aimed at conditioning and nourishing the hair rather than altering its structure or texture through heat. Thus, among the options, a keratin treatment is precisely what involves heat for straightening purposes.