Which profession necessitates knowledge of the chemical interactions of hair products?

The profession that necessitates knowledge of the chemical interactions of hair products is cosmetology. Cosmetologists are trained to understand a wide range of hair treatments, including coloring, perming, and straightening, all of which involve the application of chemical products. This understanding is crucial for safely and effectively using these products while considering the individual needs of clients, such as their hair type and condition.

In contrast, while barbers operate in a similar field and may work with some hair products, their primary focus is often on cutting and styling rather than the chemical properties of products. Estheticians deal primarily with skin care and may consider product interactions for skin health but do not typically engage with hair products as extensively as cosmetologists do. Makeup artists focus on cosmetic application and techniques and do not usually require knowledge of the chemical interactions in hair products, as their expertise lies in enhancing facial features rather than hair care.

Thus, the comprehensive training of a cosmetologist equips them with the necessary knowledge of chemical interactions, making them the best fit for this question.