Oct. 16, 2023 – People at high risk of getting type 2 diabetes lost on average more than 18% of their weight when taking the weight loss drug tirzepatide, more commonly known under the brand name Mounjaro, according to clinical trial results published over the weekend.
When also including weight loss from 12 weeks of diet and exercise before starting the medication, researchers estimated that people can lose 26.6% of their body weight, which is more than 60 pounds on average, in less than 2 years. The results approach weight loss levels seen with some bariatric surgeries, and are higher than those reported in studies for other breakthrough weight loss medicines like Ozempic and Wegovy.
But nearly 18% of people who enrolled in the study did not lose at least 5% of their body weight during the diet and exercise phase of the trial and were not eligible to go on and take the medication. The authors noted that the criteria may have inflated the average weight loss results because the medication phase didn’t include these “lifestyle non-responders.”
The results of the study were published Sunday in the journal Nature Medicine.
The medication phase lasted 17 months, during which the 579 people remaining in the study took either tirzepatide or a placebo. The average age of people in the medication phase was 46 years old, 63% were women, and 86% were White. On average, people had met obesity criteria for 15 years before taking part in the study.
The study only included people with a body mass index, or BMI, of 30 or higher, and the average starting weight was more than 240 pounds. (BMI is a combined measure of weight and height that helps indicate overweight or obesity.) To take part in the study, people could not have diabetes, but had to have one other complication of weight problems such as high blood pressure.
The researchers noted that diet and exercise typically don’t result in the scale of weight loss needed to reduce potentially life-threatening health risks of overweight and obesity. Even when people do achieve significant weight loss through diet and exercise, most regain about one-third of the weight within a year, the authors noted.
During the 12-week diet and exercise phase, people in the study followed a reduced-calorie diet, did 150 minutes of weekly physical activity, and attended counseling sessions.
The most common side effects while on the medication were digestive problems, “with most being mild to moderate in severity,” the study authors wrote.
Tirzepatide is similar to another well-known weight loss drug called semaglutide, which is the active ingredient in the diabetes medicine Ozempic and in the weight loss medicine Wegovy. Semaglutide and tirzepatide mimic naturally occurring hormones in the body that regulate how the brain manages a person’s appetite.
Mounjaro, Ozempic, and Wegovy can be difficult to get due to supply shortages, and cost at least $900 per month or more when paying out of pocket.
