Semaglutide doses in published trials

Questions about semaglutide doses come up constantly, and they almost always arrive without context. A number cited from a forum or a social-media post tells you nothing useful without knowing which trial protocol specified it, what population was enrolled, and how long the titration took. This article covers what the published trials actually used. It does not tell you what dose to take; that is a question for a prescribing clinician. The figures are sourced from peer-reviewed publications.

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.

The SUSTAIN programme: doses in type-2 diabetes trials

The SUSTAIN series (SUSTAIN-1 through SUSTAIN-10) tested semaglutide as a treatment for type-2 diabetes across a range of comparators and populations. In the pivotal cardiovascular outcomes trial, SUSTAIN-6, Marso et al. assigned patients with type-2 diabetes at high cardiovascular risk to semaglutide at 0.5 mg or 1.0 mg once weekly by subcutaneous injection, or matching placebo, for 104 weeks^[2]. The primary endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, or nonfatal stroke. The semaglutide arm produced a hazard ratio of 0.74 (95% CI 0.58 to 0.95) compared with placebo, meeting the threshold for superiority.

The 0.5 mg and 1.0 mg weekly doses used in SUSTAIN-6 correspond to the dose levels in the original authorised labels for Ozempic in the EU and US. The European Medicines Agency's EPAR for Ozempic describes these as the studied range for the type-2 diabetes indication^[4], with titration from a lower starting dose to reduce gastrointestinal side effects at initiation.

The STEP programme: doses in the obesity trials

The STEP programme (STEP-1 through STEP-8) tested semaglutide at a higher dose for chronic weight management in adults with overweight or obesity. STEP-1, Wilding et al., enrolled 1,961 adults with a BMI of 30 or above (or 27 or above with at least one weight-related condition) who did not have diabetes. The trial protocol specified semaglutide 2.4 mg once weekly by subcutaneous injection or placebo, both combined with lifestyle intervention, for 68 weeks^[1]. The STEP-1 protocol titrated participants from an initial lower dose over 16 weeks before reaching the 2.4 mg maintenance level.

The STEP-1 result was a mean body-weight reduction of 14.9% in the semaglutide group versus 2.4% on placebo. That 2.4 mg weekly figure is specific to the obesity indication and higher than the doses tested in the SUSTAIN type-2 diabetes programme. The same 2.4 mg weekly dose appeared in STEP-4, which examined what happens after discontinuation, and in the SELECT cardiovascular outcomes trial.

SELECT: the 2.4 mg dose in a cardiovascular outcomes trial

SELECT (Lincoff et al., NEJM 2023) was a cardiovascular outcomes trial that enrolled adults aged 45 or older with established cardiovascular disease and a BMI of 27 or above but no history of diabetes. The trial protocol specified once-weekly subcutaneous semaglutide at 2.4 mg versus placebo, titrated in the same escalating pattern used in STEP-1^[3]. SELECT reported that major adverse cardiovascular events occurred in 6.5% of semaglutide participants versus 8.0% on placebo over a median follow-up exceeding three years, a hazard ratio of 0.80 (95% CI 0.72 to 0.90; P less than 0.001).

SELECT is the reason the 2.4 mg weekly dose became associated with cardiovascular benefit in a population without diabetes. The trial was not testing whether that dose was appropriate for any individual patient. It was testing whether that protocol-specified dose, in that enrolled population, reduced hard cardiovascular events.

Oral semaglutide: the PIONEER programme

A separate series, PIONEER, tested oral semaglutide under the brand Rybelsus for type-2 diabetes. Because bioavailability by mouth is lower than by subcutaneous injection, the oral formulation uses a different dose range. The EMA Rybelsus product page summarises dose levels of 3 mg, 7 mg, and 14 mg once daily, taken with up to 120 ml of water on an empty stomach^[4]. These are not comparable to the subcutaneous doses from SUSTAIN or STEP: the delivery routes and pharmacokinetic profiles differ substantially.

Why context matters when reading trial doses

Dose figures from trials carry the context of the trial that produced them. The 0.5 mg and 1.0 mg figures from SUSTAIN-6 were studied in people with type-2 diabetes at elevated cardiovascular risk, over 104 weeks. The 2.4 mg figure from STEP-1 and SELECT was studied in people without diabetes, titrated over 16 weeks. Lifting a number out of that context and treating it as a general prescribing target misrepresents what the research found.

The literature does not report a single correct semaglutide dose. It reports protocols that specific trials used for specific populations to test specific hypotheses. Prescribing in clinical practice takes into account indication, comorbidities, tolerability, and the current regulatory label in each country. Per-country label information for semaglutide is on our peptide page. The trial protocols are the starting point for a prescriber-led conversation, not the answer to one.

What the literature does not yet settle

The STEP, SUSTAIN, SELECT, and PIONEER programmes do not answer every relevant question. Long-horizon data beyond four to five years of continuous use are limited. The right dose for patients who tolerate less than 2.4 mg but still show meaningful weight loss is not settled. Paediatric data exist from the STEP TEENS programme but that clinical area is still developing. And the kidney-outcomes picture in obesity without diabetes has not been tested at scale. These gaps are why trials continue running.