For which type of medications is a prescription most often required?

A prescription is most often required for controlled substances due to their potential for abuse, dependence, and the serious consequences associated with their misuse. This category of medications is regulated by federal and state laws to ensure public safety. Controlled substances are classified into schedules based on their accepted medical use and the level of regulation required to mitigate risks of abuse.

In contrast, over-the-counter medications can be purchased without a prescription as they are deemed safe for the public to self-medicate with, provided they follow label directions. Herbal supplements and vitamins or minerals also do not typically require prescriptions since they are considered dietary supplements and are not classified the same way as controlled substances. The requirement for a prescription for controlled substances reflects the need for professional oversight in their use, ensuring they are prescribed only when medically necessary and used safely.