STEP 12: semaglutide 2.4 mg, Chinese adults

The STEP programme from Novo Nordisk has been enrolling participants in obesity and weight-management trials for semaglutide 2.4 mg weekly since the early STEP 1 through STEP 8 trials. Most of those trials recruited predominantly Western populations using a BMI threshold of 30 or above. STEP 12 is different: it enrolled 242 adults from mainland China and Taiwan using the lower BMI cut-offs that Chinese clinical guidelines apply, and it ran for 44 weeks rather than the 68-week duration used in STEP 1.^[1]

The results, published online 10 August 2026 in Lancet Diabetes & Endocrinology (PMID 42575111), show that semaglutide produced a 12.1% mean body-weight reduction versus 2.2% on placebo, a treatment difference of 9.9 percentage points (95% CI 11.8 to 8.0; p less than 0.0001).^[1]

Why a separate trial for Chinese adults

BMI-based obesity definitions are not universal. Chinese clinical guidelines define overweight as a BMI of 24 to below 28 and obesity as 28 or above, compared with the WHO global thresholds of 25 and 30 respectively. These lower cut-offs reflect consistent evidence that metabolic risk in East Asian populations rises at lower BMI values than in European populations.

STEP 12 enrolled participants with a BMI of 24 to below 28 who also had at least one weight-related comorbidity, or participants with a BMI of 28 to below 30. This is a population that most earlier STEP trials would not have enrolled at all. The trial tested whether semaglutide 2.4 mg produces meaningful weight reduction in that specific range, where the efficacy question was genuinely open.^[1]

The primary endpoint

The trial randomised 242 adults 2:1 (161 semaglutide, 81 placebo) across 19 sites in mainland China and Taiwan. Enrollment ran from September 2023 to May 2025. The co-primary endpoints were percentage change in body weight at 44 weeks and the proportion of participants achieving at least 5% weight loss.^[1]

Mean body-weight reduction was 12.1% (SE 0.6) in the semaglutide group versus 2.2% (SE 0.8) in the placebo group. At the 5% responder threshold, 80.5% of semaglutide participants met the target compared with 24.4% on placebo (odds ratio 14.8; 95% CI 7.4 to 29.6; p less than 0.0001).^[1]

For context, STEP 1 (Wilding et al., NEJM 2021) enrolled 1,961 adults with BMI of 30 or above (or 27 with a weight-related condition) and ran for 68 weeks. That trial reported mean weight loss of 14.9% on semaglutide versus 2.4% on placebo.^[2] The STEP 12 figure of 12.1% is lower, but the populations are different in BMI distribution and the trial was shorter. A direct comparison requires caution.

Safety profile

Adverse events occurred in 87.6% of participants on semaglutide and 75.3% on placebo. The pattern is consistent with the established safety profile of the GLP-1 receptor agonist class. Gastrointestinal disorders were the most common adverse event type, including nausea, diarrhoea, vomiting, and constipation, matching what STEP 1 and subsequent trials in other populations reported.^[1]

The trial was funded by Novo Nordisk, and multiple authors disclosed industry relationships. The publication reports an adverse-event safety profile consistent with the known semaglutide class profile, with no new safety signals identified in this Chinese cohort.

What STEP 12 adds to the evidence base

The main contribution of STEP 12 is population-specific: it confirms that semaglutide 2.4 mg produces clinically meaningful weight reduction in Chinese adults at the lower BMI thresholds used in Chinese clinical practice. Earlier trials did not answer this question because their enrollment criteria excluded most of this population. The 12.1% mean weight loss over 44 weeks is a substantial effect in participants who would not have met the inclusion criteria for STEP 1.^[1]

The trial also included participants with type-2 diabetes: 47 of 242 (19.4%). The full publication will allow stratified analysis of outcomes in that subgroup. For the broader question of how the semaglutide evidence base applies to East Asian populations, STEP 12 is now the most directly relevant data point.

What this does not tell us

STEP 12 was not designed to compare outcomes against tirzepatide or other agents in the same population. The 44-week duration does not capture long-term durability or what happens to weight after treatment stops. Regulatory approval in China and Taiwan will depend on the full trial dataset and ongoing regulatory review, not on this publication alone. The trial does not resolve questions about cardiovascular outcomes in Chinese adults on semaglutide; that evidence base remains from other trials in other populations.

The study enrolled at lower BMI thresholds than most STEP trials, which is the right question for China-specific clinical practice. Whether those results translate to other East Asian populations with similar BMI cut-offs (Japan, Korea, Taiwan) is a question for future research.

Medical disclaimer: This article is for educational and journalistic purposes only and does not constitute medical advice. Peptides discussed may be classified as prescription medicines depending on your jurisdiction. Always consult a qualified healthcare professional before using any peptide product. PeptideMethods.com does not sell, distribute, or facilitate the sale of any peptide product.