Qsymia vs Wegovy: Weight Loss Trials, Dosing, Safety

Qsymia vs Wegovy at a Glance

Wegovy carries a boxed warning for thyroid C-cell tumor risk, while Qsymia requires a REMS program for embryo-fetal toxicity. The two medications come from different drug classes and are not compared head-to-head in the sources we read. Wegovy provides a choice between once-weekly subcutaneous injections and once-daily oral tablets. Qsymia is an oral capsule taken once every morning. Qsymia is classified as a Schedule IV controlled substance due to its phentermine component.

For another GLP-1 comparison, see Wegovy vs Zepbound.

How Each Is Taken

Wegovy is available as a once-weekly subcutaneous injection and as once-daily oral tablets, whereas Qsymia is strictly a once-daily morning capsule. The Wegovy prescribing information lists injection strengths of 0.25 mg, 0.5 mg, 1 mg, 1.7 mg, 2.4 mg, and 7.2 mg. For oral administration, the label lists tablet strengths of 1.5 mg, 4 mg, 9 mg, and 25 mg.

Patients starting Wegovy subcutaneous injections begin at 0.25 mg once weekly for four weeks. The prescriber then escalates the dose through scheduled increments toward the usual recommended maintenance dosage of 2.4 mg once weekly. The label also recognizes 1.7 mg once weekly as an alternative maintenance dosage for weight reduction. Wegovy is prescribed as an adjunct to diet and increased physical activity.

Qsymia must be taken orally once daily in the morning, avoiding evening doses to prevent insomnia. Patients begin Qsymia at a starting dosage of 3.75 mg/23 mg daily for 14 days. Prescribers then step patients up to the 7.5 mg/46 mg daily dose. Depending on individual weight-loss response, the dosage can be escalated further to 11.25 mg/69 mg and up to the highest strength of 15 mg/92 mg daily.

The label says the 15 mg/92 mg dose should be gradually discontinued to prevent possible seizure. In patients with moderate or severe renal impairment, or moderate hepatic impairment, Qsymia dosing must not exceed 7.5 mg/46 mg daily. Additional details on oral formulations appear in our overview of oral GLP-1 pills.

What the Trials Showed

Clinical trials for Wegovy and Qsymia evaluated different patient populations over different treatment durations; there is no head-to-head trial. Wegovy's primary data spans 68 weeks, while Qsymia's pivotal trials concluded at 56 weeks. Each trial measured mean body-weight reductions relative to placebo.

In Study 2 of the Wegovy injection clinical program, 1,306 adults with obesity, or overweight with at least one comorbidity, received Wegovy 2.4 mg once weekly. Participants recorded a mean body-weight change of -14.9% at 68 weeks, compared to -2.4% for the 655 participants in the placebo group. The difference from placebo reached -12.4% (95% confidence interval, -13.3 to -11.6). Baseline mean weight was 105.4 kg in the Wegovy group and 105.2 kg in the placebo group.

In Study 3, which evaluated 404 adults with type 2 diabetes and overweight or obesity, Wegovy 2.4 mg produced a -9.6% mean weight change at 68 weeks versus -3.4% across 403 placebo recipients, establishing a treatment difference of -6.2%. The Wegovy label notes that adverse-reaction discontinuation rates and efficacy findings for a higher 7.2 mg dose exist in separate studies, though 7.2 mg figures are not presented here. To explore these trial endpoints further, see our review of Wegovy benefits.

Qsymia demonstrated weight reduction across two major 56-week trials with Study 1 using intent-to-treat analysis with last observation carried forward. In Study 1, conducted in adults with obesity whose baseline weight averaged about 115 kg, placebo recipients experienced a -1.6% mean weight change. Participants assigned to Qsymia 3.75 mg/23 mg had a mean weight change of -5.1%, while those taking the top dose of 15 mg/92 mg achieved a -10.9% mean change.

In Study 2, evaluating adults with obesity or overweight and comorbidities with a baseline mean weight of about 103 kg, the placebo group showed a -1.2% change. Patients taking Qsymia 7.5 mg/46 mg achieved a -7.8% reduction, while the 15 mg/92 mg group reached a -9.8% mean reduction. In this study, 70% of participants on 15 mg/92 mg lost at least 5% of their starting weight, and 48% lost at least 10%. Early study withdrawal prior to week 56 was documented at 40% in Study 1 and 31% in Study 2.

Safety Warnings Side by Side

Wegovy carries a boxed warning regarding the risk of thyroid C-cell tumors, while Qsymia carries warnings regarding embryo-fetal toxicity, increase in heart rate, suicidal behavior and ideation, ophthalmologic adverse reactions (acute myopia, secondary angle-closure glaucoma), mood and sleep disorders, cognitive impairment, metabolic acidosis, decrease in renal function, and serious skin reactions. The Wegovy label notes that semaglutide causes thyroid C-cell tumors at clinically relevant exposures in rodents, it is unknown whether Wegovy causes thyroid C-cell tumors in humans, including medullary thyroid carcinoma. Beyond its boxed warning, the Wegovy highlights document risks of hypoglycemia when used with insulin or insulin secretagogues. They also warn of acute kidney injury from volume depletion, hypersensitivity reactions including anaphylaxis and angioedema, and severe gastrointestinal adverse reactions. Wegovy is not recommended for individuals with severe gastroparesis. Common gastrointestinal patterns are examined further in our guide to GLP-1 side effects.

The Qsymia prescribing information outlines serious fetal toxicity warnings. Qsymia can cause fetal harm when administered to a pregnant woman. A negative pregnancy test is recommended before starting therapy and monthly throughout treatment, combined with effective contraception. Qsymia is available through a limited program under a Risk Evaluation and Mitigation Strategy (REMS).

Additional warnings for Qsymia include increase in heart rate, suicidal behavior and ideation, metabolic acidosis, cognitive impairment, mood and sleep disorders, serious skin reactions, and decreases in renal function. Qsymia also carries warnings for ophthalmologic adverse reactions, including acute myopia and secondary angle-closure glaucoma. In Study 1, Qsymia was associated with a mean heart rate increase of +1.1 to +1.8 beats per minute versus placebo at the highest dose, with the label observing that one year of therapy improved several risk factors versus placebo except heart rate.

The most common adverse reactions reported for Qsymia in adults, occurring at a rate of at least 5% and at least 1.5 times placebo, include paraesthesia, dizziness, dysgeusia, insomnia, constipation, and dry mouth. Contraindications for Qsymia include pregnancy, glaucoma, hyperthyroidism, hypersensitivity to sympathomimetic amines or components, and concurrent use or use within 14 days of monoamine oxidase inhibitors (MAOIs).

Who Each Is For

Both medications carry indications for adults with obesity, or overweight with at least one weight-related comorbid condition. Wegovy is indicated to reduce excess body weight and maintain weight reduction long term in adults with obesity, or in adults with overweight in the presence of at least one weight-related comorbid condition. Concomitant use of Wegovy tablets or injection with other semaglutide products or any other GLP-1 receptor agonist is not recommended.

Qsymia is indicated as an adjunct to a reduced-calorie diet and increased physical activity for chronic weight management in adults with a baseline BMI of 30 kg/m2 or greater, or 27 kg/m2 or greater with at least one weight-related comorbidity such as hypertension, type 2 diabetes, or dyslipidemia. The Qsymia label also includes an indication for pediatric patients aged 12 and older with a BMI in the 95th percentile or greater. The effect of Qsymia on cardiovascular morbidity and mortality has not been established. Qsymia is contraindicated in pregnancy, glaucoma, hyperthyroidism, taking or within 14 days of stopping MAOIs, and known hypersensitivity to a component or sympathomimetic amines. For Wegovy, the label carries a boxed warning for risk of thyroid C-cell tumors (it is unknown whether Wegovy causes them in humans, including medullary thyroid carcinoma) and notes it is not recommended in severe gastroparesis.

Cost, Coverage and Access

Price, insurance coverage, and availability vary for both drugs; check with your prescriber and health plan. For Wegovy tablet cost details only, see our guide to Wegovy pill cost.

The Verdict: Which Is the Better Fit?

In our comparison of the two prescribing-information documents, Wegovy demonstrates the larger mean weight reduction in its separate pivotal trial data, while Qsymia offers a daily oral capsule option for patients who cannot or will not use a GLP-1 receptor agonist. The Wegovy label reports a -14.9% mean weight change at 68 weeks with its 2.4 mg injection, whereas Qsymia achieved -9.8% to -10.9% across its 56-week trials at the highest studied dose. We did not run clinical tests on either drug, and no head-to-head trial exists to compare them directly.

This comparison does not recommend initiating, switching, or discontinuing any prescription medicine. Qsymia is contraindicated in pregnancy, glaucoma, hyperthyroidism, hypersensitivity, and with or within 14 days of MAOIs. Several conditions can flip the choice. These include questions for the prescriber about personal or family thyroid C-cell tumor history (Wegovy boxed warning) and severe gastroparesis (Wegovy is not recommended). Other factors include GI tolerance questions for the prescriber (given Wegovy warnings for severe gastrointestinal adverse reactions), heart-rate concerns from Qsymia warnings, as well as cost and insurance coverage.

Our evaluation would shift if a direct head-to-head clinical trial demonstrated different comparative outcomes, or if updated safety labeling altered the risk profile of either drug. The Qsymia label carries an FDA notice that it may not be the latest approved version; the Qsymia label is the June 2022 version on file, whereas the Wegovy label reflects a June 2026 revision. Take the next step with our assessment.

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