--- title: "STEP 8: Semaglutide Phase 3b Results | Primara Labs" url: https://www.primaralabs.com/research/trials/step-8 source: Primara Labs, markdown mirror of the HTML page --- # STEP 8 In STEP 8, a phase 3b trial of semaglutide in US adults with BMI of 30 or greater, or 27 or greater with 1 or more weight-related comorbidities, without diabetes (n=338), mean body weight fell 15.8% on semaglutide 2.4 mg and 6.4% on liraglutide 3.0 mg over 68 weeks, against 1.9% on placebo (pooled) (treatment-policy estimand; Rubino DM et al. JAMA 2022 (STEP 8)). Primara Labs sells some of the compounds covered here. Every figure on this page links to its source and the date it was checked. Updated 24 September 2026 Semaglutide Explained: STEP, SUSTAIN and SELECT Trials (Philippines)2:07·[Transcript and chapters](https://www.primaralabs.com/videos/semaglutide) ## Results Mean percent change in body weight by arm, as each source reports it. Navy bars are the trial arms, grey bars the comparator. Bars from different trials are not a head-to-head comparison: populations, durations and estimands differ. ## Side effects reported In STEP 8, discontinuation because of adverse events was 3.2% on semaglutide 2.4 mg and 12.6% on liraglutide 3.0 mg, against 3.5% on placebo (pooled). The most frequently reported adverse events were gastrointestinal disorders in 84.1% on semaglutide 2.4 mg and 82.7% on liraglutide 3.0 mg against 55.3% on placebo (pooled), nausea in 61.1% on semaglutide 2.4 mg and 59.1% on liraglutide 3.0 mg against 22.4% on placebo (pooled), constipation in 38.9% on semaglutide 2.4 mg and 31.5% on liraglutide 3.0 mg against 23.5% on placebo (pooled) and diarrhoea in 27.8% on semaglutide 2.4 mg and 18.1% on liraglutide 3.0 mg against 25.9% on placebo (pooled). | Event | Semaglutide 2.4 mg | Liraglutide 3.0 mg | Placebo (pooled) | | --- | --- | --- | --- | | Discontinuation for adverse events | 3.2% | 12.6% | 3.5% | | Gastrointestinal disorders | 84.1% | 82.7% | 55.3% | | Nausea | 61.1% | 59.1% | 22.4% | | Constipation | 38.9% | 31.5% | 23.5% | | Diarrhoea | 27.8% | 18.1% | 25.9% | | Vomiting | 25.4% | 20.5% | 5.9% | Design ## Trial design and sources Compound Semaglutide Phase 3b Population US adults with BMI of 30 or greater, or 27 or greater with 1 or more weight-related comorbidities, without diabetes Participants randomised 338 Duration 68 weeks Primary endpoint Percentage change in body weight, semaglutide vs liraglutide at week 68 Estimand treatment-policy Read out 1 January 2022 Semaglutide against liraglutide was open-label; each was blinded against its own placebo, pooled. - Rubino DM et al. JAMA 2022 (STEP 8) [open](https://doi.org/10.1001/jama.2021.23619) · checked 23 September 2026 - ClinicalTrials.gov NCT04074161 [open](https://clinicaltrials.gov/study/NCT04074161) · checked 23 September 2026 - Registry: NCT04074161 Questions ## STEP 8, answered ### What did STEP 8 find? In STEP 8, a phase 3b trial of semaglutide in US adults with BMI of 30 or greater, or 27 or greater with 1 or more weight-related comorbidities, without diabetes (n=338), mean body weight fell 15.8% on semaglutide 2.4 mg and 6.4% on liraglutide 3.0 mg over 68 weeks, against 1.9% on placebo (pooled) (treatment-policy estimand; Rubino DM et al. JAMA 2022 (STEP 8)). ### What side effects were reported in STEP 8? In STEP 8, discontinuation because of adverse events was 3.2% on semaglutide 2.4 mg and 12.6% on liraglutide 3.0 mg, against 3.5% on placebo (pooled). The most frequently reported adverse events were gastrointestinal disorders in 84.1% on semaglutide 2.4 mg and 82.7% on liraglutide 3.0 mg against 55.3% on placebo (pooled), nausea in 61.1% on semaglutide 2.4 mg and 59.1% on liraglutide 3.0 mg against 22.4% on placebo (pooled), constipation in 38.9% on semaglutide 2.4 mg and 31.5% on liraglutide 3.0 mg against 23.5% on placebo (pooled) and diarrhoea in 27.8% on semaglutide 2.4 mg and 18.1% on liraglutide 3.0 mg against 25.9% on placebo (pooled). Related ## More on semaglutide - [STEP 1](https://www.primaralabs.com/research/trials/step-1) - [STEP 2](https://www.primaralabs.com/research/trials/step-2) - [STEP 3](https://www.primaralabs.com/research/trials/step-3) - [STEP 4](https://www.primaralabs.com/research/trials/step-4) - [STEP 5](https://www.primaralabs.com/research/trials/step-5) - [SELECT](https://www.primaralabs.com/research/trials/select) - [SURMOUNT-5](https://www.primaralabs.com/research/trials/surmount-5) - [Evidence Map: Semaglutide](https://www.primaralabs.com/research/evidence#semaglutide) - [Semaglutide 15mg](https://www.primaralabs.com/marketplace/semaglutide-15mg)