Can you buy phentermine without a prescription?

Phentermine is a weight-loss drug classified as a schedule III controlled substance and may not be possessed without a valid prescription, explains the U.S. Drug Enforcement Administration. Phentermine is the most commonly prescribed stimulant for dieting purposes and is frequently encountered on the illicit market.

Penalties for possession of schedule III controlled substances such as phentermine vary depending on the state and the amount of pills. An individual convicted of possession of phentermine may face fines, probation or jail time, states Nolo. At the federal level, an individual convicted of possession of phentermine faces up to 10 years in prison and a $500,000 fine, according to the DEA.