Prescription Weight Loss Medications Compared
Last updated October 27, 2026
Short answer: Prescription weight loss medications range from about 3% to 21% average weight loss in their trials. The GLP-1 based ones led: Zepbound (up to 20.9%), Wegovy (14.9%) and the oral pill Foundayo (up to 11.1%). Older options averaged less: Qsymia 9.8%, Saxenda 7.4%, Contrave 5.4% to 8.1%, and orlistat (Xenical) about 3 percentage points over placebo. These come from separate trials, so treat them as a guide, not a ranking.
Results from the labels
| Medication | How it is taken | Trial length | Average loss | Placebo |
|---|---|---|---|---|
| Zepbound (tirzepatide), 15 mg | Weekly injection | 72 weeks | 20.9% | 3.1% |
| Wegovy (semaglutide), 2.4 mg | Weekly injection | 68 weeks | 14.9% | 2.4% |
| Foundayo (orforglipron), 17.2 mg | Daily pill | 72 weeks | 11.1% | 2.1% |
| Qsymia (phentermine and topiramate), 15 mg/92 mg | Daily capsule | 56 weeks | 9.8% | 1.2% |
| Saxenda (liraglutide), 3 mg | Daily injection | 56 weeks | 7.4% | 3.0% |
| Contrave (naltrexone and bupropion) | Daily tablet | 56 weeks | 5.4% (8.1% with intensive counseling) | 1.3% (4.9%) |
| Xenical (orlistat), 120 mg | Capsule with meals | 1 year | 13.4 lbs (about 3 percentage points more than placebo) | 5.8 lbs |
| Lomaira (phentermine) | Daily tablet | Short term | Approved for a few weeks only | Not applicable |
Qsymia's lower-BMI study (BMI 27 or higher with two or more conditions) is shown. In its obesity study (BMI 35 or higher) the top dose averaged 10.9% against 1.6% on placebo. The Contrave and Qsymia figures use the label's intention-to-treat analysis. The Zepbound, Wegovy and Foundayo figures are for people without type 2 diabetes.
Why these numbers are not a ranking
- Each came from a different trial, with different people, doses, lengths and analysis methods.
- Many people dropped out of the older studies. In Contrave's trials 45% of the placebo group and 46% of the Contrave group withdrew before week 56, and 24% on Contrave stopped because of an adverse reaction versus 12% on placebo.
- In Qsymia's trials, 40% and 31% of people withdrew before week 56 in the two studies.
- In Foundayo's main trial, 22% to 24% stopped the drug across doses, against 30% on placebo.
What each type does
- GLP-1 based (Zepbound, Wegovy, Foundayo, Saxenda): work on appetite and stomach emptying pathways. See what GLP-1 is.
- Qsymia: a combination of phentermine, an appetite suppressant that is a sympathomimetic amine, and topiramate.
- Contrave: a combination of naltrexone and bupropion.
- Xenical (orlistat): inhibits lipases, the gut enzymes that digest fat.
- Lomaira (phentermine): approved as a short-term add-on of a few weeks.
Who they are for
The weight management labels for Zepbound, Wegovy, Foundayo, Contrave and Qsymia cover adults with obesity, or overweight with at least one weight-related condition, used with a reduced-calorie diet and increased physical activity. Wegovy and Qsymia also cover teens 12 and older with obesity. Each has its own warnings and side effects. See BMI requirements for the label wording, and is GLP-1 safe? for the safety picture on that class.
What to ask your prescriber
- Which of these fits my health history and the other medicines I take?
- How much weight loss is realistic, and what is the plan if I do not reach it?
- What are the common side effects, and which ones mean I should call?
- What happens to my weight if I stop? See what happens when you stop a GLP-1.
Related: weight loss injections, GLP-1 medications list and do GLP-1s work?
Sources
- Wegovy prescribing information (revised 06/2026)
- Zepbound prescribing information (revised 08/2026)
- Foundayo (orforglipron) prescribing information
- Qsymia prescribing information
- Saxenda prescribing information
- Contrave prescribing information
- Xenical prescribing information
- Lomaira prescribing information
See what the GLP-1 trial averages could mean for your own numbers.
Try the Free GLP-1 CalculatorMedical Disclaimer
This calculator is for educational and informational purposes only and does not provide medical advice, diagnose any condition, recommend or prescribe treatment, or guarantee results. Estimates are based on information you provide and published clinical-trial averages. Individual results can vary significantly.
Estimates are based on average outcomes reported in the STEP 1 (semaglutide) and SURMOUNT-1 (tirzepatide) clinical trials. Individual results can vary significantly and are influenced by factors such as dosage, diet, and adherence.
Do not start, stop, or change any medication based on the results of this calculator. Always consult a qualified healthcare professional regarding medications, treatment options, risks, side effects, and your individual health needs.