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ObesityMarch 2021

What the STEP 1 Trial Found — Semaglutide for Weight Loss in Obesity

STEP 1 tested semaglutide, a once-weekly injection (the same drug sold as Wegovy for weight management and Ozempic for diabetes), in 1,961 adults with overweight or obesity but without type 2 diabetes. Over 68 weeks, people on semaglutide lost an average of about 15% of their body weight — roughly 34 pounds for someone starting at 230.

What the trial was testing

The STEP 1 enrolled 1,961 patients with obesity. The study was sponsored by Novo Nordisk and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

~15% average body weight loss on weekly semaglutide vs. ~2.4% on placebo at 68 weeks.

New England Journal of Medicine · 2021 · NCT03548935

These findings — that average body weight loss on once-weekly semaglutide vs. placebo at 68 weeks — were published in the New England Journal of Medicine and represent the headline result of the study.

Researchers tracked outcomes across 1,961 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with obesity, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

Semaglutide for weight management is FDA-approved as Wegovy and available now (supply has been tight on and off). It's a once-weekly injection that you give yourself at home. Coverage is the biggest barrier — many insurers don't pay for weight-management indications even though they cover the same drug for diabetes. Ask your doctor about eligibility and check Novo Nordisk's savings programs if you have commercial insurance.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.