For many years, treating obesity didn’t seem quite as respectable as other medical specialties. Worse, the patients who sought that treatment were viewed with scorn by many people in society, including some health care professionals. Even though more than 40% of American adults are classified as obese, weight stigma is still a serious problem.
That may start to change as our understanding of the causes and treatment of this condition shift. Presenting excess fat as a simple matter of personal responsibility (“eating too much” or “not exercising enough”) overlooks the many complex factors driving this condition (The Lancet Public Health, Nov. 1, 2019).
Now, a new crop of medications that can help people lose weight is gaining attention. The role of insulin, and particularly, a hormone that regulates its levels called glucagon-like peptide 1 (GLP-1), has risen to prominence in less than two decades. Back in 2005, the Food and Drug Administration approved a drug for Type 2 diabetes called exenatide (Byetta). It works through the GLP-1 receptor to help people normalize their blood sugar.
Don’t yawn just yet. The pharmaceutical industry, sensing it might be on to something interesting, kept working on compounds that can activate GLP-1 receptors.
The first drug that took this approach for weight loss was liraglutide (Saxenda). One of the trials that led to its approval showed 62% of patients on Saxenda lost at least 5% of their body weight in a year, compared to 34% of those taking placebo. Digestive side effects such as nausea, vomiting, diarrhea, constipation and reduced appetite may have kept Saxenda out of the headlines.
Then along came semaglutide (Wegovy). Like other drugs in its category, it is a GLP-1 receptor agonist. Unlike other medicines, however, it helped people shed an average 15% of their body weight in just over a year. People on placebo lost a little over 2% in the same time frame.
The FDA approved Wegovy for weight loss in 2021, but what really pushed it into the limelight was social media. When Elon Musk announced on Twitter that it had helped him lose weight, lots of people wanted to try it.
That may not be the last word, though. Tirzepatide (Mounjaro) is also a GLP-1 agonist. The FDA approved it for treating Type 2 diabetes in 2022. But the excitement is building around an ongoing clinical trial, called SURMOUNT, testing its use for weight loss. In the first phase of the trial, people injecting Mounjaro lost more than 20% of their body weight. Those on placebo lost about 3%.
