What the STEP Trials Show About Semaglutide for Weight Loss
A plain-language summary of the STEP trial program evidence for semaglutide weight loss, including the landmark STEP 1 result, for telehealth patients.
How much weight does semaglutide cause in clinical trials?
In the landmark STEP 1 trial (New England Journal of Medicine, 2021), adults with obesity taking semaglutide 2.4 mg lost about 14.9% of body weight on average over 68 weeks, versus about 2.4% with placebo, alongside lifestyle support. Later STEP trials reinforced this across different populations.
Disclaimer: American Telehealth Review is an editorial resource and does not provide medical advice, diagnosis, or treatment. Compounded medications are not FDA-approved finished drug products and should only be prescribed when clinically appropriate by a licensed healthcare provider. Brand-name medications such as Ozempic, Wegovy, Mounjaro, and Zepbound are FDA-approved under their own applications. Compounded semaglutide and compounded tirzepatide are not FDA-approved finished drug products.
The STEP program in brief
The STEP trials evaluated once-weekly semaglutide 2.4 mg for chronic weight management. STEP 1 established the headline ~14.9% average reduction; subsequent trials examined type 2 diabetes, intensive behavioral therapy, and longer-term treatment.
How trial results translate
Trial averages reflect supervised conditions with lifestyle support. Real-world results vary with adherence, dose, and care quality. Compounded semaglutide is not the FDA-approved product studied in STEP. Compare programs on oversight and true monthly cost.
Mean weight loss in pivotal GLP-1 trials
| Medication | Trial (year) | Mean weight loss |
|---|---|---|
| Tirzepatide 15 mg | SURMOUNT-1 (2022) | 20.9% |
| Tirzepatide | SURMOUNT-5 (2025) | 20.2% |
| Semaglutide 2.4 mg | STEP 1 (2021) | 14.9% |
| Semaglutide 2.4 mg | SURMOUNT-5 (2025) | 13.7% |
| Oral semaglutide 25 mg | OASIS-4 (2025) | 13.6% |
| Oral orforglipron 36 mg | ATTAIN-1 (2025) | 12.4% |
Data shown in the chart above. Compounded versions are not the FDA-approved products studied in these trials.
Frequently asked questions
How much weight loss does semaglutide cause?
About 14.9% on average over 68 weeks in STEP 1, with lifestyle support; individual results vary.
Is compounded semaglutide the same as the STEP trial drug?
No; STEP used FDA-approved semaglutide, not a compounded product.
Sources
- Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). N Engl J Med. 2021.
- Rubino D et al. Effect of continued semaglutide vs placebo on weight maintenance (STEP 4). JAMA. 2021.
- U.S. FDA — Medications containing semaglutide and tirzepatide; Compounding and the FDA (fda.gov).