A new weight loss drug called Saxenda was approved on Dec. 23 by the Food and Drug Administration (FDA). 

Before approving the drug Tuesday, the FDA evaluated Saxenda in three clinical trials that involved about 4,800 obese and overweight patients with and without significant weight-related conditions. During the trials, all of the patients had counseling on lifestyle modifications, reported an agency news release. 

Saxenda, which was manufactured by Novo Nordisk A/S, Bagsvaerd, Denmark, is designed to be used on obese adults, combined with physical activity and a low-calorie diet. 

The drug was only approved for obese adults with a body mass index (BMI) of 30 or greater, according the news release. Those with a BMI of at least 27 may be approved by a doctor to use the drug if they have at least one weight-related condition such as hypertension, type 2 diabetes or high cholesterol.

"Obesity is a public health concern and threatens the overall well-being of patients," Dr. James Smith, acting deputy director of the division of metabolism and endocrinology products in the FDA's Center for Drug Evaluation and Research, said in the news release. "Saxenda, used responsibly in combination with a healthy lifestyle that includes a reduced-calorie diet and exercise, provides an additional treatment option for chronic weight management for people who are obese or are overweight and have at least one weight-related comorbid condition."

The drug works by mimicking GLP-1 (glucagon-like peptide), which is a hormone made in the intestines, William Troy Donahoo, a staff physician in the Metabolic-Surgical Weight Management Department, Kaiser Permanente, Denver, said to WebMD. The GLP-1 hormone tells your brain when you are full, so this drug mimicking the hormone can help users eat less.