Semaglutide Clinical Trials & Research Guide

Discover the latest insights on semaglutide clinical trials & research, including the STEP, SUSTAIN and SELECT programmes.

Semaglutide Clinical Trials Research Guide

Semaglutide is a once-weekly GLP-1 receptor agonist developed by Novo Nordisk. It has one of the largest clinical trial evidence bases of any metabolic peptide, mainly through the SUSTAIN programme (type 2 diabetes), the STEP programme (obesity and overweight) and the SELECT cardiovascular outcomes trial. This guide summarises what those trials studied and reported, for research and educational purposes. MyPep Biotech supplies semaglutide for laboratory research use only. Not for human or veterinary use.

What is semaglutide, and why are researchers studying it?

Semaglutide is a modified GLP-1 (glucagon-like peptide-1) analogue designed to last much longer in the body than natural GLP-1, which allows once-weekly use in trials. Researchers study it as the benchmark GLP-1 compound, and newer peptides such as tirzepatide (GIP and GLP-1) and retatrutide (GIP, GLP-1 and glucagon) are usually compared against it.

The current state of semaglutide clinical trials

• SUSTAIN programme: Phase 3 trials in adults with type 2 diabetes.
• STEP programme: Phase 3 trials in adults with obesity or overweight.
• SELECT trial: a large cardiovascular outcomes trial in adults with overweight or obesity and established cardiovascular disease.
• Further studies: additional trials have explored areas such as kidney disease and heart failure. Registered studies can be searched on ClinicalTrials.gov.

What do semaglutide results show so far?

The best-known result is STEP 1, published in the New England Journal of Medicine in 2021. It enrolled 1,961 adults with obesity or overweight (without diabetes) for 68 weeks. The average body-weight reduction was about 14.9% with semaglutide 2.4mg once weekly, compared with about 2.4% with placebo.

• STEP 4 looked at what happens when treatment continues versus stops; continuing semaglutide maintained reductions, while switching to placebo led to weight regain.
• SELECT (NEJM, 2023) enrolled over 17,000 adults with cardiovascular disease and overweight or obesity, and reported a 20% lower risk of major cardiovascular events with semaglutide versus placebo.
• SUSTAIN trials reported reductions in HbA1c (a long-term blood glucose marker) in type 2 diabetes, alongside weight reductions.

The dosing schedule used in clinical research

In the STEP obesity trials, participants started on a low once-weekly dose that was increased gradually over about 16 weeks to a maintenance dose of 2.4mg once weekly, under medical supervision. This is described here only to explain how the studies were designed. It is not guidance of any kind, and MyPep Biotech products are not for human use.

Safety considerations and limitations

The most commonly reported adverse events in trials were gastrointestinal, such as nausea, diarrhoea, vomiting and constipation, mostly during dose escalation. Trials also have limitations: set populations, fixed durations and close medical monitoring, so results cannot be applied outside those settings.

How to find legitimate trials near you

Clinical trials are listed on ClinicalTrials.gov and, in the UK, through the NIHR Be Part of Research service. Each listing shows the sponsor, location, eligibility criteria and whether it is recruiting. Anyone interested in taking part should speak to a qualified healthcare professional.

How to read semaglutide trial updates without getting misled

• Check whether a figure is an average from a trial, not an individual outcome.
• Look at the trial length, population and comparison group (placebo or another treatment).
• Prefer peer-reviewed journals (NEJM, The Lancet) and trial registries over social media claims.
• Remember that headline percentages come from supervised studies.

Bottom line for researchers

Semaglutide is the most studied GLP-1 receptor agonist, with large published programmes in STEP, SUSTAIN and SELECT. For laboratory work, MyPep Biotech supplies semaglutide pens (Sema pens) from £49.99 and semaglutide vials from £29.99, labelled with strength and batch number, with same-day dispatch on weekday orders before 2pm. For laboratory research use only. Not for human or veterinary use.

Read more: Semaglutide UK Guide · Sema Pen UK Guide · Semaglutide Price UK · Semaglutide pen vs vial

Sources and further reading

• Wilding JPH et al. Once-weekly semaglutide in adults with overweight or obesity (STEP 1). New England Journal of Medicine, 2021. (nejm.org)
• Lincoff AM et al. Semaglutide and cardiovascular outcomes in obesity without diabetes (SELECT). New England Journal of Medicine, 2023. (nejm.org)
• ClinicalTrials.gov: registered semaglutide studies. (clinicaltrials.gov)
• Novo Nordisk: semaglutide clinical programme updates. (novonordisk.com)