How do drugs like Ozempic work for weight loss?

The weight-loss treatment landscape has been remade by a new class of injectable drugs, such as those sold under the names Ozempic and Wegovy. Patrick Sweeney is a professor of molecular and integrative physiology who studies the pathways and processes in the brain that govern eating and the sense of fullness, and how those pathways are altered in conditions like obesity. He talked about the new drugs with News Bureau biomedical sciences editor Liz Ahlberg Touchstone. Watch a video by Andy Savage.

What is the active drug in Ozempic and Wegovy? 

In Ozempic and Wegovy, the active drug is called glucagon-like peptide-1. GLP-1 is a natural compound that's released from your gastrointestinal tract after you consume a meal. It acts to stimulate insulin secretion, which is why it helps for type 2 diabetes, but it also acts in the brain to terminate food intake or to signal satiety. These drugs take that natural form of GLP-1 and they make it much more stable and active. This clinical form is called semaglutide. When you administer semaglutide to an individual with severe obesity, it curbs their appetite, and they essentially don't feel the need to eat as drastically. It also reduces cravings for highly palatable foods. It's been very effective at reducing body weight.

What other effects can these drugs have on the body? 

The GLP-1 receptor is expressed throughout the brain in many different regions, so these drugs can have a variety of effects in addition to their ability to reduce feeding. In terms of side effects, oftentimes, people report nausea and vomiting. These drugs also slow gastric emptying, so they slow the food passage through the GI tract. This can sometimes lead to feelings of nausea or a condition called gastroparesis. 

Can stopping the medication cause a regain of weight? 

Unfortunately, as soon as people stop the medication, they often will regain the weight. This is true not just for drugs, but also for dieting or bariatric surgery. Regaining weight is thought to occur because there are circuits in the brain that have a sense of your body weight “set point.” Once you stop taking these drugs, feeding often increases until the body weight goes back to the previous set point that you were at before taking the drugs. The mechanisms behind this weight rebound effect are still a very active area of research.  

What should someone considering these drugs know about them? Are they for everyone looking to lose weight? 

These are life-saving drugs for individuals with type 2 diabetes. They're really game-changing for individuals with very severe obesity and they work really well in those conditions. However, they're not necessarily intended just for losing a few pounds. There are other strategies such as dieting and exercise, which still should be your first options.  

I want to note that there is a shortage of these drugs, and they are amazing drugs for individuals that need them. Please make sure you consult with a medical provider to talk about whether they are right for you. Be wary of online providers or companies that are trying to sell you compounds like semaglutide. Make sure that you get these compounds from medical providers whom you can trust so you know that you're getting what it says it is.