There is no single “best” weight loss pill for everyone, but the most effective options available right now are prescription injectable medications: Zepbound (tirzepatide) and Wegovy (semaglutide). In head-to-head trials, people on Zepbound lost about 20% of their body weight, compared to about 14% on Wegovy. Both require a prescription, cost around $499 per month without insurance, and come with real tradeoffs worth understanding before you choose one.
The Six FDA-Approved Options
The FDA has approved six prescription weight loss medications for long-term use. They fall into three broad categories: weekly injections, daily injections, and oral pills.
- Zepbound (tirzepatide): Weekly injection. The newest and, by the numbers, most effective option currently available.
- Wegovy (semaglutide): Weekly injection. The first of the modern injectable weight loss drugs to gain widespread attention.
- Saxenda (liraglutide): Daily injection. An older option in the same drug class as Wegovy but less potent.
- Qsymia (phentermine-topiramate): Oral pill taken once daily. Combines a stimulant with an anti-seizure medication.
- Contrave (bupropion-naltrexone): Oral pill taken once or twice daily. Combines an antidepressant with a drug used to treat addiction.
- Xenical (orlistat): Oral pill. Also available over the counter in a lower dose called Alli.
How the Top Medications Compare
The SURMOUNT-5 trial directly compared Zepbound and Wegovy in the same patients. People taking Zepbound lost an average of 20.2% of their body weight (about 50 pounds), while those on Wegovy lost 13.7% (about 33 pounds). That gap is significant, and it’s the strongest evidence available for picking between the two.
Wegovy’s manufacturer has since tested a higher dose of semaglutide. In the STEP UP trial, the higher dose achieved 20.7% weight loss, which closes the gap considerably. That higher dose isn’t widely available yet, but it signals that the difference between these two drugs may narrow over time.
Older oral options produce more modest results. Qsymia led to 24 to 32 pounds of weight loss over 56 weeks in clinical trials. Contrave and orlistat produce smaller losses still. The over-the-counter version of orlistat (Alli) added only about 5.7 extra pounds of weight loss over a year compared to diet and exercise alone. About 40% of people taking Alli lost at least 5% of their body weight within a year, a meaningful but modest result.
How These Drugs Actually Work
Zepbound and Wegovy belong to a class of drugs that mimic hormones your gut naturally produces after eating. They work on multiple fronts at once: they slow down how fast your stomach empties, which keeps you feeling full longer after meals. They also act on appetite centers in the brain, reducing hunger and cravings between meals. And they improve how your body handles blood sugar by triggering insulin release.
The practical experience for most people is that food simply becomes less interesting. Portions shrink naturally because you feel satisfied sooner and stay satisfied longer. Zepbound targets two gut hormones (GLP-1 and GIP) rather than just one, which likely explains its edge over Wegovy in trials.
Qsymia works differently. The phentermine component is a stimulant that suppresses appetite, while topiramate (originally developed for seizures) also reduces hunger through a separate pathway. Contrave pairs an antidepressant with a drug that blocks opioid receptors, which appears to reduce the reward you get from eating. Orlistat takes a completely different approach: it blocks your body from absorbing about 25% of the fat you eat, so those calories pass through undigested.
Side Effects Across the Board
Stomach and digestive issues are the most common side effects of nearly every weight loss medication, but the pattern differs by drug. Zepbound, Wegovy, and Saxenda all frequently cause nausea, especially in the first few weeks as your dose increases. A large meta-analysis in The Lancet found that Saxenda carried the highest risk of diarrhea, indigestion, and excessive burping among the injectable options.
Contrave stands out for nausea specifically. The same analysis found it nearly quintupled the risk of nausea compared to placebo. Orlistat’s side effects are different in character: because it blocks fat absorption, eating high-fat meals can cause oily stools, gas, and urgent bowel movements.
Qsymia can increase your resting heart rate, which is worth monitoring. Its long-term effects on heart attack or stroke risk are not yet established.
One important reassurance: none of the weight loss medications evaluated in the meta-analysis increased the risk of acute pancreatitis, a concern that had circulated early on. However, both Wegovy and Saxenda did raise the risk of gallstones, a known consequence of rapid weight loss in general.
Who Should Avoid Certain Medications
All GLP-1 based drugs (Zepbound, Wegovy, and Saxenda) carry a warning related to thyroid cancer. Animal studies found an increased risk of a rare type called medullary thyroid cancer. Because of this, these medications should not be used by anyone with a personal or family history of medullary thyroid cancer or a genetic condition called MEN2 syndrome.
Qsymia should not be taken during pregnancy because topiramate is linked to birth defects. Contrave is off-limits for people with uncontrolled high blood pressure, seizure disorders, or those currently using opioid medications.
The Muscle Loss Tradeoff
One underappreciated risk with all weight loss medications is losing muscle along with fat. Studies suggest that 25% to 39% of the total weight lost on these drugs comes from lean mass rather than fat. For someone who loses 50 pounds on Zepbound, that could mean 12 to 20 pounds of muscle loss.
This matters because muscle burns more calories at rest, supports your joints, and protects against falls and frailty as you age. Most doctors now recommend strength training alongside any weight loss medication to preserve as much muscle as possible. Adequate protein intake also helps offset these losses.
What They Cost
Both Wegovy and Zepbound are available directly from their manufacturers at $499 per month for people paying out of pocket. Zepbound’s lowest starter dose is available at $349 per month. Insurance coverage varies widely: some plans cover these medications for people who meet specific criteria (typically a BMI of 30 or higher, or 27 with a weight-related health condition), while others exclude weight loss drugs entirely.
Oral options tend to cost less. Generic orlistat and the over-the-counter Alli version are the most affordable choices, though their results are also the most modest. Qsymia and Contrave fall somewhere in the middle on both cost and effectiveness.
The Only Over-the-Counter Option
Alli (low-dose orlistat) is the only FDA-approved, non-prescription weight loss medication. It blocks about 25% of dietary fat from being absorbed. The results are real but modest: an extra 5.7 pounds lost over a year compared to diet and exercise alone. It works best as a supplement to an already-structured eating plan, not as a standalone solution. If you eat high-fat meals while taking it, the undigested fat will make itself known through oily, loose stools.
Supplements marketed as weight loss pills (green tea extract, garcinia cambogia, raspberry ketones, and the like) are not FDA-approved for weight loss and have not demonstrated meaningful results in rigorous clinical trials. They are regulated as dietary supplements, which means they do not have to prove they work before being sold.
Choosing the Right Option
If maximum weight loss is the priority and you can access it, Zepbound currently has the strongest clinical results. Wegovy is a close second and has more long-term safety data, including a large trial showing cardiovascular benefits in people with heart disease. For people who prefer pills over injections, Qsymia offers meaningful weight loss in the range of 24 to 32 pounds over a year. Contrave is a reasonable option for people who also struggle with depression or are trying to quit smoking, since one of its components addresses those conditions. And Alli is worth considering if you want a low-commitment, over-the-counter starting point, understanding that its effects are modest.
All of these medications work best alongside changes in eating and activity. In clinical trials, every participant was also following a reduced-calorie diet. The drugs amplify your efforts; they don’t replace them. And for the injectable options in particular, weight regain after stopping is common, which means many people stay on them long term.