Six prescription medications are currently approved by the FDA for long-term weight management, ranging from daily pills to weekly injections. The newest options, the GLP-1 based injectables, produce the most dramatic results, with average weight loss between 12% and 20% of body weight. Which medication fits best depends on your starting weight, health history, tolerance for side effects, and budget.
To qualify for any of these prescriptions, you generally need a BMI above 30, or a BMI above 27 with a weight-related health condition like high blood pressure, type 2 diabetes, or sleep apnea. Most prescribers also expect you to be actively working on diet, physical activity, and behavioral changes alongside the medication.
GLP-1 Injectable Medications
The most effective weight loss drugs available today are weekly injections that mimic a gut hormone called GLP-1. This hormone naturally signals your brain to feel full after eating. When you take a medication that activates the same pathway, your appetite drops significantly, you feel satisfied with smaller portions, and food slows its movement through your stomach, keeping you fuller longer.
Two GLP-1 based injectables dominate the market right now:
- Semaglutide (Wegovy) targets GLP-1 receptors in the brain. In clinical trials, people lost an average of about 12% to 14% of their body weight over roughly 68 weeks.
- Tirzepatide (Zepbound) goes a step further by mimicking two hormones instead of one: GLP-1 and another called GIP. This dual action produces greater weight loss. In a head-to-head study against semaglutide, tirzepatide delivered 20.2% body weight loss compared to 13.7% for semaglutide, a 47% greater reduction overall.
An older GLP-1 drug called liraglutide (Saxenda) works through the same mechanism but requires daily injections and produces more modest results than either semaglutide or tirzepatide. It’s less commonly prescribed now that the newer options exist.
The most common side effects with all GLP-1 medications are gastrointestinal: nausea, vomiting, diarrhea, and loss of appetite. These tend to be worst when you first start or when your dose increases. That’s why doctors ramp the dose up gradually over several weeks or months rather than starting at the full amount.
Muscle Loss During Treatment
One concern with rapid weight loss on GLP-1 drugs is losing muscle along with fat. In clinical studies, roughly 40% of the total weight lost with semaglutide came from lean body mass, which is higher than the 25% typically seen with standard dieting. More recent research in both mice and humans, though, has found leaner results: lean mass accounted for closer to 20% of total weight loss, with the vast majority coming from body fat.
The takeaway is that some muscle loss happens with any significant weight loss, but resistance training and adequate protein intake can help preserve it. If you’re on one of these medications, strength exercises aren’t optional; they’re an important part of the plan.
Oral Prescription Options
Not everyone wants or qualifies for injectables. Three oral medications are approved for long-term weight management, each working through a completely different mechanism.
Phentermine-topiramate (Qsymia) combines an appetite suppressant with a drug originally developed for seizures and migraines. It’s the most effective oral option. People on the higher dose lost an average of 11% of their body weight after one year, while those on the lower dose lost 7% to 8%. You start at the lowest dose and step up every two weeks based on how you respond.
Naltrexone-bupropion (Contrave) pairs a drug used for addiction treatment with an antidepressant. Together, they act on brain circuits involved in cravings and reward. This combination isn’t appropriate for everyone. People with a history of seizures, eating disorders like anorexia or bulimia, or those who suddenly stop drinking alcohol or taking sedatives should not take it. Anyone with a personal or family history of bipolar disorder, suicidal thoughts, or other serious mental health conditions needs to discuss risks carefully before starting.
Orlistat (Xenical) works entirely differently from the others. Instead of affecting your brain or appetite, it blocks enzymes in your gut that break down fat. The prescription version prevents about 30% of the fat you eat from being absorbed; that unabsorbed fat passes through your system. A lower-dose version (Alli) is available over the counter and blocks roughly 25% of dietary fat. The tradeoff is that eating high-fat meals on orlistat can cause oily stools, gas, and urgent bowel movements, which is why many people find it hard to stick with.
Short-Term Appetite Suppressants
Phentermine on its own is one of the most widely prescribed weight loss drugs in the United States, but it’s only FDA-approved for a few weeks of use. It works by suppressing appetite, and some doctors prescribe it for longer periods off-label, though long-term safety data is limited. It’s typically used as a bridge while someone establishes new eating and exercise habits, not as a standalone solution.
What These Medications Cost
Cost is often the deciding factor. Wegovy and Zepbound are both available directly from their manufacturers at $499 per month for people paying out of pocket, with Zepbound’s starter dose priced at $349 per month. Insurance coverage varies widely. Some plans cover weight loss medications, especially when obesity-related health conditions are documented, while others exclude them entirely. The oral medications tend to cost significantly less, particularly generic orlistat.
Manufacturer savings programs, pharmacy discount cards, and prior authorizations through your insurance can all reduce what you actually pay. It’s worth checking multiple pharmacies, as prices vary.
How Results Compare Across Medications
The weight loss you can expect varies substantially by drug. Here’s a rough ranking based on clinical trial data over roughly one year of treatment:
- Tirzepatide (Zepbound): 17% to 20% of body weight
- Semaglutide (Wegovy): 12% to 14% of body weight
- Phentermine-topiramate (Qsymia): 7% to 11% of body weight
- Naltrexone-bupropion (Contrave): 5% to 8% of body weight
- Orlistat (Xenical): 5% to 7% of body weight
These are averages, which means some people lose considerably more and others less. Response to any given drug is individual. If one medication doesn’t produce meaningful results after three to six months, switching to another class is a reasonable next step.
What Happens When You Stop
Weight regain after stopping medication is common across all of these drugs. The GLP-1 injectables in particular work by continuously signaling your brain to reduce appetite. When that signal disappears, hunger returns to its previous level for most people. This is why these medications are approved for long-term, potentially indefinite use, similar to how blood pressure medication manages hypertension without curing it. The decision to stay on a weight loss drug long-term involves weighing the benefits against ongoing cost, side effects, and your individual health goals.