✓ Independent editorial reviews of U.S. telehealth providers · Updated June 1, 2026 · Educational only — not medical advice
Journal · Evidence review

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.

Published by Ranika Editorial Group LLCUpdated June 1, 2026
Direct Answer

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

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%
Mean body-weight reduction reported in pivotal trials (efficacy/treatment-regimen estimands as published). Populations and estimands differ between trials, so figures are directly comparable only within SURMOUNT-5, the one head-to-head study. Sources: STEP 1 (NEJM 2021); SURMOUNT-1 (NEJM 2022); SURMOUNT-5 (NEJM 2025); OASIS-4 (2025); ATTAIN-1 (NEJM 2025).
MedicationTrial (year)Mean weight loss
Tirzepatide 15 mgSURMOUNT-1 (2022)20.9%
TirzepatideSURMOUNT-5 (2025)20.2%
Semaglutide 2.4 mgSTEP 1 (2021)14.9%
Semaglutide 2.4 mgSURMOUNT-5 (2025)13.7%
Oral semaglutide 25 mgOASIS-4 (2025)13.6%
Oral orforglipron 36 mgATTAIN-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).

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