GET UPTO 20% OFF ON ALL THE MEDICINE USE COUPON CODE (SALE10) Phentermine is a medication primarily used as a short-term treatment for obesity. It works as an appetite suppressant by affecting the central nervous system, specifically by increasing neurotransmitter levels in the brain that help control appetite. Phentermine is typically prescribed in conjunction with diet, exercise, and behavioral modifications to promote weight loss in individuals who are obese or overweight and have certain risk factors, such as high blood pressure, high cholesterol, or diabetes.