What is phentermine? Phentermine is like an amphetamine. It animates the focal sensory system (nerves and cerebrum), which builds your pulse and circulatory strain and diminishes your hunger. Phentermine is utilized along with diet and exercise to treat heftiness, particularly in individuals with hazard factors, for example, hypertension, elevated cholesterol, or diabetes. Phentermine may likewise be utilized for purposes not recorded in this drug guide.