Which of the following is NOT one of the six major categories of controlled substances?

The correct answer is that exercise supplements are not classified as one of the six major categories of controlled substances. The six major categories typically recognized in the context of controlled substances include narcotics, stimulants, depressants, hallucinogens, anabolic steroids, and cannabis.

Exercise supplements, while they may be used to enhance athletic performance or overall health, do not fit within the legal framework that defines controlled substances, which are substances regulated by law due to their potential for abuse, addiction, or dependence. The other options—narcotics, stimulants, and hallucinogens—are all well-documented categories that are heavily regulated due to their psychoactive effects and risk of misuse. Understanding these categories is essential for compliance with health and safety regulations.