---
title: "STEP 2: Semaglutide Phase 3 Results | Primara Labs"
url: https://www.primaralabs.com/research/trials/step-2
source: Primara Labs, markdown mirror of the HTML page
---

# STEP 2

In STEP 2, a phase 3 trial of semaglutide in adults with BMI of at least 27 kg/m2 and HbA1c 7-10% (53-86 mmol/mol), diagnosed with type 2 diabetes at least 180 days before screening (n=1,210), mean body weight fell 9.6% on 2.4 mg over 68 weeks, against 3.4% on placebo (Davies M et al. Lancet 2021 (STEP 2)).

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

The most frequently reported adverse events were gastrointestinal adverse events in 63.5% on 2.4 mg and 57.5% on 1.0 mg against 34.3% on placebo.

| Event | 2.4 mg | 1.0 mg | Placebo |
| --- | --- | --- | --- |
| Gastrointestinal adverse events | 63.5% | 57.5% | 34.3% |

Design

## Trial design and sources

Compound

Semaglutide

Phase

3

Population

Adults with BMI of at least 27 kg/m2 and HbA1c 7-10% (53-86 mmol/mol), diagnosed with type 2 diabetes at least 180 days before screening

Participants randomised

1,210

Duration

68 weeks

Primary endpoint

Coprimary: percentage change in bodyweight and achievement of weight reduction of at least 5% at 68 weeks, semaglutide 2.4 mg versus placebo

Estimand

Not stated in the source read

Read out

2 March 2021

The abstract gives no body-weight figure for the 1.0 mg arm and does not name the estimand (intention to treat).

-   Davies M et al. Lancet 2021 (STEP 2) [open](https://doi.org/10.1016/s0140-6736(21)00213-0) · checked 23 September 2026
-   ClinicalTrials.gov NCT03552757 [open](https://clinicaltrials.gov/study/NCT03552757) · checked 23 September 2026
-   Registry: NCT03552757

Questions

## STEP 2, answered

### What did STEP 2 find?

In STEP 2, a phase 3 trial of semaglutide in adults with BMI of at least 27 kg/m2 and HbA1c 7-10% (53-86 mmol/mol), diagnosed with type 2 diabetes at least 180 days before screening (n=1,210), mean body weight fell 9.6% on 2.4 mg over 68 weeks, against 3.4% on placebo (Davies M et al. Lancet 2021 (STEP 2)).

### What side effects were reported in STEP 2?

The most frequently reported adverse events were gastrointestinal adverse events in 63.5% on 2.4 mg and 57.5% on 1.0 mg against 34.3% on placebo.

Related

## More on semaglutide

-   [STEP 1](https://www.primaralabs.com/research/trials/step-1)
-   [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)
-   [STEP 8](https://www.primaralabs.com/research/trials/step-8)
-   [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)