STEP 1.
A study in context.

Question & design

STEP 1 was a randomized, double-blind, placebo-controlled study of semaglutide plus lifestyle intervention. Allocation was 2:1.

Original trial report

Population & comparator

It enrolled 1,961 adults without diabetes: BMI at least 30, or at least 27 with a weight-related coexisting condition. The comparator received placebo plus lifestyle intervention.

Original trial report

Administration & duration

The study used weekly subcutaneous administration over 68 weeks. This describes the experiment, not an instruction for a reader.

Original trial report

Escalation in context

The protocol specified a 16-week escalation period, with tolerability-related modification provisions. The original methods are in sections 7.1–7.2; this summary does not reproduce a self-administration schedule.

Protocol · sections 7.1–7.2

Monitoring & oversight

The protocol includes adverse-event collection, vital signs, laboratory safety assessments, withdrawal criteria, and trial-governance provisions. Consult sections 8–9 and Appendix 3.

Protocol · sections 8–9 and Appendix 3

Reported outcomes

Mean body-weight change at week 68 was −14.9% with semaglutide and −2.4% with placebo. These are trial-group averages.

Original trial report

Adverse findings

Nausea and diarrhea were the most common semaglutide adverse events, generally transient and mild to moderate. This brief summary is not a complete safety assessment.

Original trial report

Sponsor & provenance

The public protocol names Novo Nordisk A/S as sponsor and identifies the trial as NN9536-4373 / NCT03548935.

Public study protocol

Interpretation limits

Editorial interpretation: keep this result attached to its population, comparator, trial product, and observation period. Do not extrapolate it to animal experiments, individual outcomes, or vendor quality.