Why is phentermine prescription-only?

Phentermine is prescription-only because it is a controlled substance and not safe for everyone.

It is a controlled substance because of the medication’s addictive potential. Phentermine has a chemical structure similar to that of amphetamines, so it should not be taken without supervision.

This medication also has a high potential for serious side effects, which underscores the necessity of a doctor both prescribing and supervising the administration of this medication.