Tirzepatide (sold as Zepbound) currently delivers the most weight loss of any medication on the market. In clinical trials, people taking the highest dose lost about 21% of their body weight over 72 weeks, roughly 50 to 60 pounds for someone starting at 250. Semaglutide (Wegovy) comes in a close second at around 15 to 16% body weight loss, with a newer higher-dose version pushing that closer to 19%. Beyond those two frontrunners, several other FDA-approved options exist, and the right choice depends on your body, your budget, and how you feel about weekly injections.
How the Top Medications Compare
The FDA has approved six medications for long-term weight management in adults. They fall into two broad categories: the newer injectable drugs that mimic gut hormones, and older oral combination pills that work through different pathways. The injectables produce significantly more weight loss, but they’re also more expensive and come with their own trade-offs.
Here’s how the major options stack up based on clinical trial results:
- Tirzepatide (Zepbound): 15% to 21% body weight loss depending on dose, delivered as a weekly injection. Approved for adults only.
- Semaglutide (Wegovy): About 15 to 16% body weight loss at the standard 2.4 mg dose, also a weekly injection. A newer 7.2 mg dose has shown losses around 19%. Approved for adults and children 12 and older.
- Liraglutide (Saxenda): An earlier-generation daily injection in the same drug class as Wegovy, producing more modest results. Approved for adults and children 12 and older.
- Phentermine-topiramate (Qsymia): The most effective oral option. In a large analysis, only 3 people needed to be treated for 1 to achieve at least 10% weight loss. Approved for adults and children 12 and older.
- Naltrexone-bupropion (Contrave): An oral pill that targets appetite and cravings through different brain pathways. Slightly less effective than Qsymia, with about 4 people needing treatment for 1 to hit 10% weight loss. Approved for adults.
- Orlistat (Xenical/Alli): The oldest option, available over the counter at a lower dose (Alli). It blocks fat absorption rather than suppressing appetite, and produces the least weight loss of the approved drugs.
Why Zepbound Outperforms the Rest
Tirzepatide works on two hormone receptors instead of one. Wegovy and other semaglutide-based drugs activate a single receptor (GLP-1) that slows digestion, increases fullness, and reduces cravings by acting on the brain. Tirzepatide hits that same receptor plus a second one called GIP, which appears to amplify the effects. Think of it as two overlapping signals telling your body to eat less and process energy differently.
In the landmark SURMOUNT-1 trial, the results across three dose levels were striking. People on the lowest dose (5 mg) lost 15% of their body weight. The middle dose (10 mg) produced 19.5% loss. And the highest dose (15 mg) reached 20.9%, all over 72 weeks. Those numbers represent averages, meaning some people lost considerably more and others less, but no other medication has matched those figures in head-to-head comparisons with placebo.
Wegovy: The Closest Competitor
Semaglutide at the standard 2.4 mg weekly dose has been the most-studied weight loss injectable, and it consistently produces around 15 to 16% body weight loss in trials. That’s enough to make a meaningful difference in blood pressure, blood sugar, joint pain, and overall quality of life for most people with obesity.
A higher-dose version (7.2 mg) has shown even better results in a phase 3 trial called STEP UP, with participants losing an average of 18.7% of their body weight. This puts it in the same range as the mid-dose tirzepatide results, though direct head-to-head trial data between the two drugs at their highest doses is still limited. The higher semaglutide dose is not yet widely available at this writing, but it signals that the gap between these two medications may narrow.
Oral Pills: What They Offer
Not everyone wants or can tolerate weekly injections, and oral medications remain a practical alternative. Qsymia (phentermine-topiramate) is the standout in this category. A large comparative analysis found it was the single most effective oral drug for achieving both 5% and 10% weight loss thresholds. It combines a short-term appetite suppressant with an anticonvulsant that also reduces appetite, and the combination works better than either drug alone.
Contrave (naltrexone-bupropion) works through a completely different mechanism, targeting the brain’s reward and appetite circuits. It’s particularly relevant for people whose weight is tied to emotional eating or strong food cravings, since bupropion is also used to treat depression and help with smoking cessation. The weight loss numbers are lower than Qsymia’s, but for the right person, it can be effective.
There’s also an oral form of semaglutide (Rybelsus) approved for type 2 diabetes that some doctors prescribe off-label for weight loss. A real-world study of the 14 mg tablet found an average weight loss of about 5.7% over one year, with only 4% of participants losing more than 15%. That’s notably less than the injectable version, partly because the pill form delivers a lower effective dose and partly because absorption varies depending on when and how you take it.
Side Effects Across the Board
The injectable medications share a common side effect profile rooted in how they work. Slowing digestion means nausea, vomiting, diarrhea, and constipation are the most frequent complaints, particularly during the first few weeks and during dose increases. Most people find these symptoms ease over time as the body adjusts, which is why both Zepbound and Wegovy use a gradual dose-escalation schedule over several months.
Qsymia carries different risks. The topiramate component can cause tingling in the hands and feet, difficulty concentrating, and taste changes. It’s also linked to birth defects and requires reliable contraception during use. Contrave can raise blood pressure in some people and shouldn’t be used by anyone with a seizure disorder.
Orlistat has the most distinctive side effect: because it blocks fat absorption in the gut, eating high-fat meals can cause oily stools, gas, and urgent bowel movements. These effects are directly tied to dietary choices, so they tend to decrease if you eat less fat.
Cost and Access
Price remains the biggest barrier to the most effective medications. Wegovy offers a self-pay option starting at $149 per month for certain doses, with prices reaching $349 to $399 per month at maintenance doses for those paying out of pocket. People with commercial insurance may pay as little as $25 per month through manufacturer savings programs, but coverage varies widely by plan. Zepbound pricing falls in a similar range.
The oral medications are generally less expensive, and some have generic equivalents. Orlistat is available over the counter as Alli at a reduced dose, making it the most accessible option without a prescription. Phentermine (the appetite-suppressant component of Qsymia) is also available as an inexpensive generic on its own, though it’s only approved for short-term use when prescribed alone.
Insurance coverage for weight loss medications has improved but remains inconsistent. Medicare does not currently cover most anti-obesity drugs, and many private plans still classify them as elective. Before committing to any medication, checking your specific plan’s formulary and prior authorization requirements can save you from sticker shock at the pharmacy.
Picking the Right Option
If maximum weight loss is the priority and cost isn’t a barrier, tirzepatide (Zepbound) is the strongest option currently available. Wegovy is a close second, with a longer track record and more data on cardiovascular benefits. For people who prefer pills, Qsymia offers the best results among oral options, while Contrave suits those whose eating patterns are strongly driven by cravings or emotional triggers.
Weight loss medications work best alongside changes in eating and activity, and they generally need to be continued long-term to maintain results. Most people regain a significant portion of lost weight after stopping these drugs, which is why the decision involves not just which medication works best in a trial but which one you can realistically stay on. A medication that produces 21% weight loss in a clinical trial but that you can’t afford or tolerate after six months will deliver worse real-world results than a more modest option you can sustain.