A few years ago, "GLP-1" wasn't a phrase most people outside of endocrinology had ever heard. Today, medications like semaglutide (Ozempic, Wegovy) and tirzepatide (Mounjaro, Zepbound) are some of the most talked-about drugs in the country. Here's what this drug class actually is, and what the clinical research — not the headlines — says about it.
What are GLP-1 receptor agonists, exactly?
GLP-1 stands for glucagon-like peptide-1, a hormone your gut naturally releases after you eat. It tells your pancreas to release insulin, slows down how quickly your stomach empties, and signals to your brain that you're full. GLP-1 receptor agonist medications mimic that hormone, but in a longer-acting, more potent form. The class isn't new — the first one, exenatide, was approved for type 2 diabetes back in 2005. What's new is a second generation of these drugs (semaglutide, tirzepatide) that are dramatically more effective, which is what's driven the recent surge in attention.
What does the research actually show?
Weight loss. In the clinical trials that led to Wegovy's approval, participants lost an average of roughly 15% of their body weight over about 68 weeks, on top of diet and exercise counseling. Tirzepatide's trials showed even larger average reductions, with a meaningful share of participants losing 20% or more. These are trial averages — individual results vary — but they represent a substantially larger effect than older weight-management medications.
Blood sugar control. For type 2 diabetes, GLP-1 medications consistently lower A1C (a measure of average blood sugar) and are often used specifically because they do this while also supporting weight loss, rather than causing weight gain like some older diabetes medications.
Cardiovascular outcomes. This is the research that moved GLP-1s beyond a weight-loss or diabetes story: a large semaglutide cardiovascular outcomes trial (SELECT) found a meaningful reduction in major adverse cardiovascular events — heart attack, stroke, and cardiovascular death — in people with existing cardiovascular disease and obesity, independent of diabetes status. That result is a big part of why these medications are being studied so heavily beyond their original use.
What else is being studied?
Researchers are actively studying GLP-1 medications for additional benefits, including effects on fatty liver disease, sleep apnea, kidney disease in people with diabetes, and even early signals around addiction and inflammation-related conditions. Some of this research is further along than others — sleep apnea and kidney-disease benefits have stronger trial data, while some of the other areas are still early — so it's worth treating any claim beyond weight loss, diabetes, and cardiovascular risk as an active area of research rather than a settled fact.
Who are they for, and what should you know about side effects?
These medications are prescription-only and aren't right for everyone. The most common side effects are gastrointestinal — nausea, constipation, or diarrhea, especially when starting or increasing a dose — and they carry specific precautions for people with a personal or family history of certain thyroid cancers or pancreatitis. This is exactly the kind of decision that benefits from a licensed doctor reviewing your full medical history before you start, not a one-size-fits-all approach.
How telehealth fits into getting access
Because GLP-1 medications require an ongoing prescription and regular check-ins as your dose is adjusted, telehealth has become a natural fit: a doctor can review your history, determine if you're a candidate, prescribe and adjust your dose over time, and have it shipped to you — without requiring an in-person visit every time your treatment plan needs a check-in.