Weight-loss medications, compared
Every FDA-approved weight-loss drug in one place — the injections and the pills — with what each is really approved for, the average weight loss its trial reported, the main safety warning, and our independent FDA recall-safety rating. We rate medications on their safety record; we don’t sell them or prescribe them.
The one thing that confuses everyone
Ozempic and Mounjaro are diabetes drugs, not weight-loss drugs — using them to lose weight is off-label. Their exact same molecules are FDA-approved for weight, under different brands and doses: semaglutide is Ozempic (diabetes) and Wegovy (weight); tirzepatide is Mounjaro (diabetes) and Zepbound (weight). The weight-approved brands are the ones studied and dosed for it.
Weight-loss injections
The GLP-1 and GIP/GLP-1 injectables — the drugs behind the biggest average weight loss in trials, and the most-searched category. Ranked by our recall-safety score.
Wegovy (semaglutide)
The same molecule (semaglutide) is also sold as Ozempic (once-weekly injection, for type 2 diabetes) and Rybelsus (daily oral tablet, for type 2 diabetes).
- How it’s taken
- A once-weekly subcutaneous injection (titrated over 16 weeks to the 2.4 mg maintenance dose); a once-daily 25 mg oral tablet form is also approved.
- Approved for
- FDA-approved for chronic weight management — to reduce excess body weight and maintain weight reduction long term in adults and children 12+ with obesity, or adults who are overweight with a weight-related condition; also approved to cut the risk of major cardiovascular events in adults with established CV disease plus obesity/overweight.
- Average weight loss
- In the pivotal 68-week trial (Study 2 / STEP 1, adults with obesity or overweight plus a comorbidity), patients on Wegovy 2.4 mg lost an average of 14.9% of body weight vs 2.4% on placebo — a 12.4 percentage-point difference. 83.5% lost at least 5%, 66.1% at least 10%, and 47.9% at least 15% of their body weight.
What to know
Carries an FDA Boxed Warning for risk of thyroid C-cell tumors: in rodents semaglutide caused dose- and duration-dependent thyroid C-cell tumors, and it is contraindicated in anyone with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). The label also warns of pancreatitis and gallbladder disease.
Saxenda (liraglutide)
Same molecule (liraglutide) is also sold as Victoza, which is approved for type 2 diabetes.
- How it’s taken
- a once-daily injection under the skin (titrated to 3 mg daily over 4 weeks)
- Approved for
- FDA-approved for chronic weight management (reduce excess body weight and maintain weight reduction long term) in adults with obesity, or overweight plus a weight-related comorbidity, and in patients aged 12+ over 60 kg with obesity, alongside reduced-calorie diet and increased physical activity.
- Average weight loss
- In the pivotal 56-week trial (Study 1), patients on Saxenda lost a mean 7.4% of body weight vs 3.0% on placebo (a 4.5% placebo-adjusted difference); baseline mean weight was about 106 kg. 62% of Saxenda patients lost at least 5% and 34% lost more than 10% of body weight.
What to know
Boxed warning: liraglutide causes thyroid C-cell tumors in rodents; it is unknown whether it does in humans, and Saxenda is contraindicated in anyone with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). Other GLP-1 class risks include pancreatitis and gallbladder disease.
Ozempic (semaglutide)
Also sold as Rybelsus (oral semaglutide tablets, for diabetes) and as Wegovy (semaglutide, for chronic weight management).
- How it’s taken
- a once-weekly subcutaneous injection
- Approved for
- FDA-approved for type 2 diabetes (glycemic control) and to reduce major adverse cardiovascular events in adults with type 2 diabetes and established cardiovascular disease. It is NOT approved for weight loss; weight use is off-label. The same molecule is FDA-approved for chronic weight management as Wegovy.
- Average weight loss
- Weight loss is a secondary endpoint in the diabetes trials, not an approved outcome. In the 30-week monotherapy trial (SUSTAIN 1), mean body weight fell about 3.8 kg (~8 lb) on the 0.5 mg dose and 4.7 kg (~10 lb) on the 1 mg dose, versus 1.2 kg (~3 lb) on placebo, from a baseline of roughly 90-97 kg.
What to know
Boxed warning for risk of thyroid C-cell tumors (medullary thyroid carcinoma); contraindicated in people with a personal or family history of MTC or Multiple Endocrine Neoplasia syndrome type 2 (MEN 2). The label also warns of pancreatitis and gallbladder disease.
Zepbound (tirzepatide)
Also sold as Mounjaro (for type 2 diabetes)
- How it’s taken
- a once-weekly subcutaneous injection
- Approved for
- FDA-approved for chronic weight management in adults with obesity, or overweight with at least one weight-related condition (also approved for moderate-to-severe obstructive sleep apnea in adults with obesity).
- Average weight loss
- In the pivotal SURMOUNT-1 trial (Study 1, 72 weeks), mean body-weight reduction was 15.0% on 5 mg, 19.5% on 10 mg, and 20.9% on 15 mg, versus 3.1% for placebo.
What to know
Carries a boxed warning for risk of thyroid C-cell tumors (including medullary thyroid carcinoma); it is contraindicated in anyone with a personal or family history of MTC or with Multiple Endocrine Neoplasia syndrome type 2 (MEN 2), and the label also warns of pancreatitis and gallbladder disease.
Mounjaro (tirzepatide)
Also sold as Zepbound (tirzepatide), which IS the FDA-approved brand for chronic weight management and obstructive sleep apnea.
- How it’s taken
- a once-weekly subcutaneous injection
- Approved for
- FDA-approved for type 2 diabetes (as an adjunct to diet and exercise to improve glycemic control); not approved for weight. Weight use is off-label — the same molecule, tirzepatide, is FDA-approved for chronic weight management under the brand Zepbound.
- Average weight loss
- Mounjaro's own label is a diabetes label and does not carry a weight-management indication or pivotal weight trial. For tirzepatide's weight effect, the pivotal obesity trial (SURMOUNT-1 / Study 1, 72 weeks, adults with obesity or overweight without type 2 diabetes) — reported on the Zepbound label — showed a mean reduction in body weight of 15.0% at 5 mg, 19.5% at 10 mg, and 20.9% at 15 mg once weekly, versus 3.1% on placebo.
What to know
Carries a BOXED WARNING for the risk of thyroid C-cell tumors (contraindicated in anyone with a personal or family history of medullary thyroid carcinoma or MEN 2); label also warns of pancreatitis and gallbladder disease. Not a controlled substance.
Weight-loss pills
The oral options — generally a smaller average weight loss than the injections, but no needle, and some are far cheaper. Ranked by our recall-safety score.
Qsymia (phentermine and topiramate)
- How it’s taken
- a once-daily oral extended-release capsule
- Approved for
- FDA-approved for chronic weight management — in adults with obesity, or overweight plus at least one weight-related condition, and in patients aged 12 and older with obesity — alongside a reduced-calorie diet and increased physical activity.
- Average weight loss
- At the recommended top dose (15 mg/92 mg), average (least-squares mean) weight loss from baseline at Week 56 (1 year) was about 10.9% of body weight in Study 1 (obesity) and 9.8% in Study 2 (overweight/obesity with comorbidities), versus roughly 1.2–1.6% on placebo — a placebo-adjusted difference of about 8.6–9.4%.
What to know
Contraindicated in pregnancy — topiramate raises the risk of major birth defects including cleft lip/cleft palate — so pregnancy must be ruled out before starting and effective contraception used during treatment; it also contains phentermine, a Schedule IV controlled substance, and is contraindicated in glaucoma or hyperthyroidism.
Contrave (naltrexone and bupropion)
- How it’s taken
- a twice-daily oral tablet, taken morning and evening, dose-escalated over 4 weeks to the maintenance dose of two 8 mg/90 mg tablets twice daily (32 mg naltrexone / 360 mg bupropion per day)
- Approved for
- FDA-approved for chronic weight management — to reduce excess body weight and maintain weight reduction long term in adults with obesity, or overweight with at least one weight-related comorbidity, alongside a reduced-calorie diet and increased physical activity.
- Average weight loss
- In the pivotal 56-week COR-I trial, patients on CONTRAVE lost on average 5.4% of body weight versus 1.3% on placebo (ITT/LOCF); 42% of CONTRAVE patients lost at least 5% of body weight versus 17% on placebo.
What to know
Boxed warning for suicidal thoughts and behaviors — CONTRAVE contains bupropion, an antidepressant, which increased suicidal thinking and behavior in children, adolescents, and young adults; it is not approved for pediatric use. It also carries a seizure risk (contraindicated in patients with seizure disorders). If a patient has not lost at least 5% of body weight after 12 weeks at the maintenance dose, the label says to discontinue.
Xenical (orlistat)
Also sold over-the-counter as Alli (60 mg).
- How it’s taken
- an oral capsule, 120 mg taken three times a day with each main meal containing fat
- Approved for
- FDA-approved for obesity management (weight loss and weight maintenance) alongside a reduced-calorie diet, for a BMI of 30 or higher (or 27+ with risk factors like hypertension, diabetes, or dyslipidemia).
- Average weight loss
- Pooled data from five 1-year trials: mean weight loss at 1 year was 13.4 lbs on Xenical vs 5.8 lbs on placebo (intent-to-treat), a mean difference of about 3% of body weight. Of patients who completed the year, 57% on Xenical vs 31% on placebo lost at least 5% of baseline body weight.
What to know
Works by blocking absorption of dietary fat, which causes the hallmark GI effects (oily/fatty stools, fecal urgency, gas with discharge) and reduces absorption of fat-soluble vitamins — the label says to take a multivitamin with vitamins A, D, E, K and beta-carotene. Contraindicated in pregnancy, chronic malabsorption, and cholestasis; rare cases of severe liver injury and of oxalate kidney injury have been reported. Not a controlled substance.
phentermine (phentermine)
Also sold as Adipex-P and Lomaira; combined with topiramate as Qsymia.
- How it’s taken
- a daily pill (usual adult dose one 37.5 mg tablet before or 1-2 hours after breakfast; late-evening dosing avoided due to insomnia)
- Approved for
- FDA-approved as a short-term (a few weeks) adjunct to diet, exercise, and behavioral modification for exogenous obesity (BMI >=30, or >=27 with risk factors).
- Average weight loss
- The label reports no percent-of-body-weight figure. Its Clinical Studies section states only that drug-treated patients lost more weight than placebo, with the magnitude of the extra weight loss being "only a fraction of a pound a week," greatest in the first weeks, over trials of a few weeks' duration — an effect the label calls "clinically limited."
What to know
Short-term use only (a few weeks); a Schedule IV controlled substance with abuse potential. Contraindicated in cardiovascular disease (coronary artery disease, stroke, arrhythmias, heart failure, uncontrolled hypertension), hyperthyroidism, glaucoma, agitated states, history of drug abuse, MAO-inhibitor use within 14 days, and pregnancy/nursing.
How to read the weight-loss numbers
Each average comes from that drug’s own pivotal trial, alongside diet and exercise — not a head-to-head study, so the percentages are notdirectly comparable, and your result can be more or less. Weight also tends to return after stopping. A bigger trial average is not a reason to choose a drug on your own: the safety warnings, your other conditions and medicines, cost and access all matter, and that weighing is a prescriber’s job. Also see the deeper GLP-1 comparison and GLP-1 side effects. Thinking of getting one online? Our GLP-1 telehealth comparison shows which services prescribe the FDA-approved drug versus a compounded copy.
See a clinician online
Licensed online providers — consult & get prescribed if eligible.
Most weight-loss telehealth services dispense COMPOUNDED semaglutide or tirzepatide — a copy the FDA has not reviewed for identity, potency, purity or sterility. The shortages that made routine compounding lawful ended (tirzepatide October 2024, semaglutide February 2025), and in 2026 the FDA has been issuing warning letters over how compounded GLP-1s are marketed. If you want the FDA-approved branded drug, say so and check which service prescribes it.
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Frequently asked questions
Is Ozempic a weight-loss drug?
Ozempic is FDA-approved for type 2 diabetes, not weight loss — using it for weight is off-label. Its exact same molecule, semaglutide, IS FDA-approved for chronic weight management, but under a different brand and dose: Wegovy. The same is true of Mounjaro (diabetes) and Zepbound (weight loss), which are both tirzepatide.
What is the most effective weight-loss medication?
In the pivotal trials, the injectable GLP-1 and GIP/GLP-1 drugs produced the largest average weight loss — Wegovy (In the pivotal 68-week trial), Zepbound (In the pivotal SURMOUNT-1 trial) — more than the older oral options. But the trials are not head-to-head, "most effective on average" is not "best for you," and the right choice depends on your health, side-effect tolerance, cost and access — a prescriber's decision.
Are weight-loss injections safe?
The GLP-1 injections carry an FDA boxed warning about a risk of thyroid C-cell tumours seen in rodents, and can cause pancreatitis and gallbladder problems; the oral options have their own serious warnings (Contrave's suicidality boxed warning, Qsymia's pregnancy contraindication). None is a casual choice. Read each drug's warning above and take the decision to a prescriber.
Sources: each drug’s FDA label (openFDA / DailyMed), linked on its card. Weight-loss figures are the averages the pivotal trials reported and are reproduced, not computed by us. This is general reference information, not medical advice, and not a recommendation to take any drug.