Talk about GLP-1 medicines usually starts and ends with the number on the scale. Large trials now show two more GLP-1 benefits that matter just as much for the decades ahead. These medicines help your cells answer insulin again, and they lower inflammation. Here is how each benefit works and what the studies found.
What GLP-1 does in your body
GLP-1 is a hormone your gut releases after you eat. It tells the rest of your body that food has arrived. Your own GLP-1 breaks down within minutes. GLP-1 medicines copy the hormone and stay active far longer.
GLP-1 sends four messages:
- It tells your pancreas to release insulin while your blood sugar runs high.
- It lowers glucagon, a hormone that tells your liver to release stored sugar.
- It slows how fast your stomach empties after a meal.
- It tells your brain you have eaten enough.
Semaglutide and tirzepatide are the two GLP-1 medicines most people know. Tirzepatide acts on GLP-1 and on a second gut hormone named GIP.
Weight loss is the first GLP-1 benefit you notice
Fullness comes sooner, and food cravings get quieter. Many people eat less without a daily fight against hunger.
The STEP 1 trial tested semaglutide in 1,961 adults without diabetes. Both groups in the trial also followed a lifestyle program. After 68 weeks, people on semaglutide had lost 14.9 percent of their body weight on average. People on placebo lost 2.4 percent. The New England Journal of Medicine published the results in 2021.
Weight loss brings one risk you can manage. Part of the weight you lose can come from muscle. Muscle keeps you strong on the trail, and it also pulls sugar out of your blood. Protein at each meal and regular strength training help you keep it. Our posts on protein during weight loss and macros and weight lifting on a GLP-1 explain how.
How GLP-1 eases insulin resistance
Insulin moves sugar out of your blood and into your cells. With insulin resistance, your cells stop answering insulin well. Your pancreas then makes more insulin to keep your blood sugar in range. Over years, that extra work can lead to prediabetes and then type 2 diabetes.
GLP-1 medicines help in two ways.
First, they act on blood sugar directly. GLP-1 raises insulin only while your blood sugar runs high. When your blood sugar falls back to normal, the extra insulin stops. For that reason, a GLP-1 medicine used alone carries a low risk of low blood sugar.
Second, they shrink the fat that drives insulin resistance. Fat deep in the belly and fat inside the liver both make insulin resistance worse. As that fat drops, your cells answer insulin better. Fasting blood sugar and A1C often come down with it.
The STEP 1 numbers show the size of the change. A follow-up analysis looked at the trial members who started with prediabetes. After 68 weeks, 84.1 percent of them on semaglutide had normal blood sugar. On placebo, 47.8 percent did. Diabetes Care published that analysis in 2022.
Our post on GLP-1 and insulin resistance goes deeper on this part of the story.
The anti-inflammatory benefits of GLP-1
Inflammation is your body’s repair response. A cut swells, then heals. Trouble starts when low-grade inflammation never switches off. Over years, that steady inflammation strains your blood vessels and feeds insulin resistance.
A blood test called C-reactive protein, or CRP, measures this background inflammation.
Weight loss tends to lower CRP. GLP-1 medicines appear to lower it further. Chi Kin Wong and Daniel Drucker of the University of Toronto reviewed the research in the Journal of Clinical Investigation in 2025. Their review describes a trial called PIONEER 2, in adults with type 2 diabetes. The trial compared oral semaglutide with empagliflozin, which belongs to another class of diabetes medicines. Both produced a weight loss of about 4 percent. Semaglutide lowered CRP by 30 percent, and CRP stayed the same on empagliflozin.
The review adds a second finding from two larger groups of semaglutide trials. Lower blood sugar and lower weight explained only 20 to 60 percent of the drop in CRP. So GLP-1 medicines seem to calm inflammation through a separate route as well.
Early studies in mice point to one possible route. In those studies, GLP-1 medicines lowered a key inflammatory signal, TNF-alpha, only when nerve cells in the brain carried GLP-1 receptors. Researchers still need to test this route in people.
Our post on GLP-1 and body inflammation covers what chronic inflammation does over time.
What the SELECT trial found for your heart
The SELECT trial followed 17,604 adults with overweight or obesity and existing heart disease. None of them had diabetes. Over an average of 40 months, 6.5 percent of people on semaglutide had a major heart event, such as a heart attack or stroke. The trial also counted deaths from heart disease in that total. On placebo, 8.0 percent had a major heart event. That works out to a 20 percent lower risk. The New England Journal of Medicine published the results in 2023.
People on semaglutide in SELECT lost about 9 percent of their body weight by two years. Researchers still debate how much of the heart benefit came from that weight loss. Lower inflammation and better insulin action likely play a part too.
What GLP-1 medicines ask of you
A GLP-1 medicine works best as one part of a plan. It does its work alongside the food you eat and the way you move.
Side effects are common at the start. Nausea and stomach upset often show up in the first weeks and then fade for most people. Less common problems include gallbladder inflammation and pancreatitis.
A GLP-1 medicine is a poor fit during pregnancy. The same goes for anyone with a personal or family history of medullary thyroid cancer, a rare type, or a related gene condition called MEN 2. Your provider reviews your health history with you before you start.
How Contours approaches GLP-1 care
Those benefits and those cautions both shape how we start. At Contours, GLP-1 care begins with a conversation. Your provider first decides whether a GLP-1 medicine fits your health history and your goals. When it fits, we build the plan around your life. You get nutrition guidance and ongoing monitoring along the way. Visits take place by telehealth, so care fits around your schedule.
Our medical weight loss program page explains what that care looks like. When you want to talk through whether a GLP-1 fits you, start the conversation. Bring your questions with you.