Confirming weight loss on Semaglutide: the STEP2 Trial

Confirming weight loss on Semaglutide: the STEP2 Trial
Photo by Dan Dimmock / Unsplash

The STEP1 Trials which were conducted in June 2018 were already a great step forward for the treatment of type 2 diabetes and weight control, but as with the best science, it's always good to confirm, repeat and conduct experiments to find truth.

Want to read more about the STEP1 Trials? We've got you covered

The STEP2 trials were conducted at a similar time, but had less participants than the STEP1 trials (1210 participants). You can find out more about the trials from

Research Study Investigating How Well Semaglutide Works in People With Type 2 Diabetes Suffering From Overweight or Obesity - Full Text View -
Research Study Investigating How Well Semaglutide Works in People With Type 2 Diabetes Suffering From Overweight or Obesity - Full Text View.

The study summary is nice and easy to read:

This study will look at the change in the participant's body weight from the start to the end of the study. This is to compare the effect on body weight in people taking semaglutide (a new medicine) and people taking "dummy" medicine. In addition to taking the study medicine, the participant will have talks with study staff about healthy food choices, how to be more physically active and what else the participant can do to lose weight. Overweight and obesity is associated with an increased risk of type 2 diabetes. Therefore, weight loss has shown to have a beneficial impact on the blood sugar levels. The participant will either get semaglutide or "dummy" medicine - which treatment the participant get is decided by chance. The participant will need to take 2 injections at the same time once a week. The study medicine is injected with a thin needle in a skin fold in the stomach, thigh or upper arm. The study will last for about 1.5 years

After completion the study was published in the Lancet, where we can read the results, summed up very quickly in the Interpretation section:

In adults with overweight or obesity, and type 2 diabetes, semaglutide 2·4 mg once a week achieved a superior and clinically meaningful decrease in bodyweight compared with placebo.

These are stunning results, but how did they get there?

How was the STEP1 Trial different from the STEP2 Trial?

Where the STEP1 trial only tested Semaglutide versus a Placebo, STEP2 tested two doses of Semaglutide:

  • Semaglutide 1.0mg
  • Semaglutide 2.4mg

Much like STEP1, the trial was conducted at many sites across many countries:

  • Argentina (5 sites)
  • Canada (10 sites)
  • Germany (9 sites)
  • Greece (6 sites)
  • India (18 sites)
  • Japan (12 sites)
  • Russian Federation (9 sites)
  • South Africa (6 sites)
  • Spain (8 sites)
  • United Arab Emirates (5 sites)
  • United Kingdom (10 sites)
  • United States (51 sites)

What were the results of the STEP2 Trial?

The STEP2 trial confirmed much of the results of the STEP1 trial.

Patients on Semaglutide 2.4mg lost 9.9% to 10.7% of their body weight while participants on Placebo lost 3.3% to 3.1%, a statistically significant difference.

The difference in treatment during the trial was 6.21% (estimated) and during the treatment as a whole 7.57% (estimated). Statistically significant improvements in weight control were demonstrated by Semaglutide, once again.

During the trial, another key outcome measured was losing >=5% of body weight, which happened for 68.8% of participants who took semaglutide during the trial, compared with 28.5% who were on the placebo.

Was Semaglutide 2.4mg more effective than 1.0mg?

Another interesting bit that was put to the test during this study was whether there was a difference between Semaglutide at 2.4mg dosage versus 1.0mg dosage.

The study found that participants under Semaglutide 2.4mg lost an average of 9.9% of their body weight, compared to 7.2% on Semaglutide 1.0mg.

When it comes to losing >=5% of body weight, 68.8% of Semaglutide 2.4mg participants did, compared to 57% of Semaglutide 1.0mg participants.

Clearly, there's an increased effect of higher doses of Semaglutide, though the difference is clearly not as stark as compared to placebo.

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