The most popular weight loss drugs right now are semaglutide (sold as Wegovy) and tirzepatide (sold as Zepbound), both weekly injections that belong to a class of medications mimicking natural gut hormones. These two drugs have dominated headlines since their approvals because they produce significantly more weight loss than anything previously available, with patients losing 14% to 20% of their body weight in clinical trials.
The Drugs Everyone Is Talking About
Six prescription medications are FDA-approved for long-term weight management: orlistat (Xenical/Alli), phentermine-topiramate (Qsymia), naltrexone-bupropion (Contrave), liraglutide (Saxenda), semaglutide (Wegovy), and tirzepatide (Zepbound). But it’s the last two that have reshaped how people think about obesity treatment.
Wegovy and Zepbound work in a fundamentally different way from older weight loss pills. They mimic hormones your gut naturally releases after eating, signaling to your brain that you’re full. The result is a dramatic reduction in appetite. People on these medications consistently describe losing interest in food, thinking about meals less often, and feeling satisfied after eating far smaller portions than before.
You may also have heard of Ozempic, which contains the same active ingredient as Wegovy (semaglutide) but is approved specifically for type 2 diabetes, not weight loss. Wegovy goes up to a higher maximum dose of 2.4 mg per week compared to Ozempic’s 2 mg cap, making it the more effective option for weight management. Doctors sometimes prescribe Ozempic off-label for weight loss, which has contributed to shortages for people with diabetes who need it.
How Much Weight People Actually Lose
In a head-to-head clinical trial of 751 people, tirzepatide (Zepbound) produced an average weight loss of 20.2% of body weight, significantly outperforming semaglutide (Wegovy) at 13.7%. About 89% of participants in that trial reached the highest tirzepatide dose of 15 mg. For someone weighing 250 pounds, that translates to roughly 50 pounds lost with Zepbound versus 34 pounds with Wegovy.
The difference comes down to biology. Wegovy targets one gut hormone pathway (GLP-1), while Zepbound targets two (GLP-1 and GIP), giving it a broader effect on appetite and metabolism. Both produce results that were essentially unheard of with earlier weight loss medications, which typically helped people lose only 5% to 10% of their body weight.
What Taking These Medications Looks Like
Both drugs are self-administered injections, given once a week using a pen-style device similar to what people with diabetes use for insulin. You inject into your stomach, thigh, or upper arm. The needle is short and thin enough that most people describe the injection itself as painless or mildly uncomfortable.
Neither drug starts at full strength. Semaglutide begins at 0.25 mg weekly, increasing by 0.25 mg every four weeks until reaching the target dose of 2.4 mg. That ramp-up takes 16 to 20 weeks. Tirzepatide starts at 2.5 mg and increases by 2.5 mg every four weeks, up to a maximum of 15 mg. This gradual approach exists entirely to manage side effects, giving your body time to adjust.
Side Effects and What to Expect
Nausea is the most common complaint. In clinical trials, about 19% of people on GLP-1 medications experienced nausea compared to 6.5% on placebo. Vomiting affected roughly 8% versus 2% on placebo. These symptoms are most likely when you first start the medication or step up to a higher dose, and they typically fade over the first few weeks at each new level. More than half of trial participants reported no gastrointestinal side effects at all.
About 6.5% of people in clinical trials stopped taking the medication because of side effects, with nausea being the leading reason, followed by vomiting and diarrhea. In real-world use, those discontinuation rates tend to be somewhat higher, particularly among people over 65.
Early concerns about pancreatitis and pancreatic cancer have largely been put to rest by long-term trial data. These drugs do slow how quickly your stomach empties (that’s part of how they work), which means food can sit in your stomach longer than usual. This is worth knowing if you’re scheduled for surgery or an endoscopy, since your doctor may ask you to stop the medication beforehand to reduce the chance of complications from retained food.
The Muscle Loss Question
One important concern that gets less attention than side effects: these medications don’t only burn fat. Studies show that 25% to 39% of the total weight lost comes from lean mass, which includes muscle. Lose 40 pounds, and roughly 10 to 15 of those pounds may be muscle rather than fat. This matters because muscle supports your metabolism, joint stability, and overall physical function, especially as you age.
Resistance training and adequate protein intake can help counteract this effect. Most obesity medicine specialists now recommend strength exercises at least two to three times per week while on these medications, though the drugs themselves don’t come with that guidance on the label.
Cost Without Insurance
Both manufacturers recently cut prices for people paying out of pocket. Wegovy now costs $499 per month, down 23% from its previous price of $650. Zepbound’s starter dose dropped to $349 per month, with higher doses at $499. These prices apply to uninsured patients and those whose insurance doesn’t cover weight loss medications.
Insurance coverage varies widely. Many employer plans and Medicare Part D still exclude weight loss drugs, though that landscape is shifting as more data emerges on the medications’ cardiovascular benefits. Wegovy now carries FDA approval for reducing heart disease risk in adults with obesity and established cardiovascular disease, which has pushed some insurers to expand coverage. If your insurance does cover these drugs, copays can range from $25 to several hundred dollars depending on your plan.
Beyond Weight Loss: Expanded Approvals
Wegovy’s approved uses have grown beyond weight management alone. It now has FDA clearance for treating a form of fatty liver disease (called MASH) in adults with moderate or advanced liver scarring, and for reducing cardiovascular risk in adults with obesity or overweight who also have heart disease. It’s also approved for weight management in children aged 12 and older. These expanding indications reflect a broader shift in how these drugs are viewed: not just as weight loss tools but as treatments for the downstream health consequences of excess weight.