The main finding
In one sentence: Among people with prediabetes at the start of STEP 1, 84.1% on weekly semaglutide 2.4 mg and 47.8% on placebo had normal-range blood sugar at week 68, and in STEP 3 the figures were 89.5% and 55.0%, all measured while people were still on treatment.
Group averages, not an individual prediction. A trial result describes what happened to a defined group over a defined time.
On this page
Why this study matters
Prediabetes means blood sugar is higher than normal but not yet in the range for type 2 diabetes. Many adults living with obesity have it. The STEP trials were designed to measure weight loss with semaglutide (Wegovy, Ozempic), but the researchers also planned in advance to check what happened to blood sugar status. This paper reports those results. For Canadian readers with prediabetes, it answers a narrow question: while on the medicine, did more people move back into the normal range?
Who was in the study
The paper analyzed 3,375 adults with overweight or obesity across three trials: STEP 1, STEP 3 and STEP 4. All had no diabetes at the start. Across the three trials, 1,536 people had prediabetes at the start.
This page covers only the STEP 1 and STEP 3 results. The STEP 4 results and the more detailed blood-test analyses in the paper were added after the fact (post hoc), so they were not included in our evidence review. STEP 1 and STEP 3 each ran for 68 weeks.
What the researchers did
STEP 1 and STEP 3 were phase 3, randomized, placebo-controlled trials in many countries. Randomized means chance decided who got which treatment. Placebo means an inactive injection. In both, people received semaglutide 2.4 mg injected once a week or placebo, plus lifestyle support, for 68 weeks. STEP 3 used a more intensive behavioural program than STEP 1.
At the start and at week 68, each person's glycemic status was classified as normal, prediabetes or diabetes, based on blood tests. The change in status from week 0 to week 68 was a prespecified outcome in STEP 1 and STEP 3, meaning it was written into the plan before the trials began. The measurement at week 68 was taken before any washout period, so people were still on the medicine.
The analysis used a treatment-policy estimand, meaning it counted everyone randomized regardless of whether they stayed on treatment. Missing values were filled in with a statistical method called multiple imputation. No adjustment was made for testing several outcomes at once.
What they found
Among people with prediabetes at the start, more had normal-range blood sugar at week 68 with semaglutide than with placebo (R32-C39).
| Trial | Normal blood sugar at week 68, semaglutide | Normal blood sugar at week 68, placebo |
|---|---|---|
| STEP 1 | 84.1% | 47.8% |
| STEP 3 | 89.5% | 55.0% |
Both differences were very unlikely to be chance (P less than 0.0001).
The paper also looked at people who had normal blood sugar at the start. Fewer of them had moved into the prediabetes range at week 68 with semaglutide than with placebo: 2.9% versus 10.9% in STEP 1, and 3.2% versus 5.8% in STEP 3.
The published summary we reviewed does not report a between-group difference with a confidence interval for these outcomes.
Side effects and people who stopped
This paper reports blood sugar outcomes only. The summary we reviewed does not report adverse events or how many people stopped treatment. For side effects in these trials, see the STEP 1 and STEP 3 pages.
What this study does not tell you
- Blood sugar was measured while people were still taking semaglutide, with no washout. The study cannot say whether the improvement lasts after stopping (R32-C40).
- It shows a change in a lab category, not a reduction in diagnosed diabetes or in complications like heart or kidney disease.
- These were secondary outcomes of weight-loss trials, not the main question the trials were built to answer, and no adjustment was made for multiple comparisons.
- This page leaves out the STEP 4 results and the post hoc analyses in the same paper, because they were not planned in advance.
- Both groups had lifestyle support, so the result shows what the medicine added on top of it.
- The number of people with prediabetes in STEP 1 and STEP 3 specifically was not extracted from the paper.
What it means in Canada
Prediabetes is common in Canada, and lifestyle programs have their own evidence for reducing progression to diabetes. This analysis shows that, while on semaglutide 2.4 mg, more people with prediabetes returned to the normal range than on placebo. It does not show what happens after treatment ends. For how the medicine is used here, see semaglutide in Canada and public drug coverage by province.
Common questions
Did semaglutide return blood sugar to normal in people with prediabetes?
Among STEP 1 participants with prediabetes at the start, 84.1% on semaglutide and 47.8% on placebo had normal-range blood sugar at week 68. In STEP 3 the figures were 89.5% and 55.0%.
Does this mean semaglutide prevents type 2 diabetes for good?
No. Blood sugar was measured while people were still taking the medicine, with no washout, so the study cannot say whether the improvement lasts after stopping.
Was this a separate trial?
No. It is an analysis of blood sugar outcomes that were planned in advance within the STEP 1 and STEP 3 weight-loss trials.
Related reading
Other studies in this library that bear on the same question.
STEP 1: semaglutide weight loss trial in adults
STEP 3: semaglutide with intensive behavioural therapy
SELECT: did semaglutide prevent diabetes in people with heart disease?
Diabetes Prevention Program: lifestyle versus metformin
Source
Original paper: Leigh Perreault, STEP 1/3 prespecified glycemic-status outcomes (mixed-analysis paper), Diabetes care, 2022. PubMed: https://pubmed.ncbi.nlm.nih.gov/35724304/. DOI: https://doi.org/10.2337/dc21-1785. Funding: The summary we reviewed does not state the funding source. How we summarized it: full text and extracted data.
This page explains a published study. It is not medical advice and does not describe whether a medicine is right for you. Talk to your doctor, nurse practitioner or pharmacist about your own situation. Reviewed and signed by two pharmacists registered in British Columbia, 2026-09-18.
Evidence records behind this page
Each record is a row in the clinical evidence file, taken from the published paper named above. The caution column is the limit the researcher recorded for that number.
This table scrolls sideways.
| Record | What the paper reports | Type | Population | Caution | Source |
|---|---|---|---|---|---|
| R32-C39 | Among STEP 1 participants with prediabetes at baseline, 84.1% receiving semaglutide and 47.8% receiving placebo had normal-range glycemia at week 68. | direct evidence | Adults with overweight/obesity without diabetes; subgroup with prediabetes | Mixed-analysis paper retained only for prespecified STEP 1/3 glycemic-status outcomes; STEP 4 and post hoc HbA1c/FPG/HOMA subgroup analyses excluded. No washout before assessment; cannot establish persistence after stopping. | PubMed 35724304 |
| R32-C40 | These STEP glycemic assessments occurred while participants were being treated, without a washout, so they cannot establish that improvement persists after medication stops. | direct evidence | Adults with overweight/obesity without diabetes; subgroup with prediabetes | Mixed-analysis paper retained only for prespecified STEP 1/3 glycemic-status outcomes; STEP 4 and post hoc HbA1c/FPG/HOMA subgroup analyses excluded. No washout before assessment; cannot establish persistence after stopping. | PubMed 35724304 |