If a product label and the Safety Data Sheet give safety instructions, the cosmetologist should:

Cosmetologists should always follow the manufacturer's directions and safety instructions found on the product label and the Safety Data Sheet — including how to use, store, dilute, and handle the product, and what protective equipment to wear. These instructions exist to ensure the product works correctly and is used safely, protecting both the professional and the client. Disregarding label or SDS guidance can cause poor results, injury, or chemical exposure. Following manufacturer and SDS instructions is a basic, exam-tested safety expectation.