Editorial commentary on published literature
Semaglutide and liraglutide: what the published trial data and UK regulatory record report
This page is editorial commentary on the published clinical literature for two GLP-1 receptor agonist medicines licensed in the UK for weight management: semaglutide (marketed as Wegovy by Novo Nordisk) and liraglutide (marketed as Saxenda by Novo Nordisk). It summarises what the STEP-1 and SCALE trials reported, references the relevant NICE technology appraisals (TA875, TA664) and the MHRA licensing record, and notes the UK regulatory framework. Both are prescription-only medicines. PeptideClear does not recommend a medicine for any individual. Any prescribing decision is between a patient and a UK-licensed prescriber.
Published trial outcomes referenced on this page
- · STEP-1 (semaglutide, weight management, N Engl J Med 2021, PMID 33567185). Mean body weight reduction reported at 68 weeks in adults with overweight or obesity without type 2 diabetes.
- · SCALE Obesity and Prediabetes (liraglutide 3.0 mg, weight management, N Engl J Med 2015, PMID 26132939). Mean body weight reduction reported at 56 weeks in adults with overweight or obesity.
- · SELECT (semaglutide, cardiovascular outcomes in adults with overweight or obesity and established CV disease, N Engl J Med 2023, PMID 37952131). Basis for the cardiovascular outcome indication added to the semaglutide label.
Note: no published head-to-head randomised trial compares semaglutide and liraglutide on a weight-management endpoint. The figures cited come from separate placebo-controlled trials and are not directly comparable.
Reference table: published characteristics
| Characteristic | Semaglutide | Liraglutide |
|---|---|---|
| Active molecule | Semaglutide | Liraglutide |
| UK marketing authorisation holder | Novo Nordisk (brand: Wegovy) | Novo Nordisk (brand: Saxenda) |
| Mechanism described in the literature | GLP-1 receptor agonist (longer-acting) | GLP-1 receptor agonist (shorter-acting) |
| Dosing frequency on the SmPC | Once-weekly subcutaneous injection | Once-daily subcutaneous injection |
| UK launch (weight management indication) | 2022 | 2017 |
| Pivotal weight-management trial | STEP-1: mean body weight reduction approximately 15 per cent at 68 weeks | SCALE: mean body weight reduction approximately 8 per cent at 56 weeks |
| NICE technology appraisal | TA875 (semaglutide for weight management) | TA664 (liraglutide 3.0 mg for weight management) |
| NHS access framework (2026) | Restricted access under TA875. CV outcome indication broadens reimbursement on the CV-prevention route from April 2026. | Restricted access under TA664. Largely superseded in UK prescribing practice by longer-acting GLP-1 receptor agonists since 2023. |
| Private route pricing observed in the UK market | Reported in the £150 to £300 per month range | Reported in the £200 to £350 per month range |
| Storage (SmPC) | Refrigerated; once in use, up to 6 weeks at room temperature per SmPC | Refrigerated; once in use, up to 4 weeks at room temperature per SmPC |
Sources: SmPC entries on the MHRA Products database, NICE technology appraisal documents (TA875, TA664), and the cited New England Journal of Medicine publications. Pricing reflects publicly listed UK private route ranges and is not a quotation.
What the literature and UK regulatory record describe
Liraglutide 3.0 mg was the first daily GLP-1 receptor agonist licensed for weight management in the UK (Saxenda, 2017). Semaglutide (Wegovy) followed in 2022 as a once-weekly preparation in the same drug class. The published placebo-controlled trials report different mean weight reductions: approximately 15 per cent at 68 weeks in STEP-1 for semaglutide, approximately 8 per cent at 56 weeks in SCALE for liraglutide. These figures are not from a head-to-head trial.
Since 2023, UK prescribing observation suggests that semaglutide and tirzepatide have largely displaced liraglutide in private weight-management prescribing, reflecting the larger reported trial effect and the weekly dosing schedule on the SmPC. NHS access for both semaglutide and liraglutide is restricted under their respective NICE appraisals (TA875 and TA664) to defined BMI thresholds, comorbidity criteria, and specialist weight-management service settings.
Adverse event profiles described in the SmPCs for both medicines are dominated by gastrointestinal events (nausea, vomiting, diarrhoea, constipation). Refer to the current SmPC entries on the MHRA Products database for the full list and frequency tables.
UK regulatory and access framework
- · Both medicines are prescription-only (POM) under the Human Medicines Regulations 2012. They may only be supplied against a prescription written by a UK-registered prescriber.
- · The MHRA is the UK regulator that holds the marketing authorisations. Current SmPCs and patient information leaflets are published on the MHRA Products database.
- · NICE technology appraisals TA875 (semaglutide) and TA664 (liraglutide) set the NHS eligibility criteria for each medicine.
- · The CMA, ASA and MHRA jointly regulate UK advertising of POM. Branded consumer-facing comparison advertising of POM is not permitted. This page is editorial commentary on the public clinical record and does not advertise any product to any individual.
- · If a UK-licensed prescriber raises one of these medicines in a consultation, the published trial reports linked above describe the evidence base they may be drawing on.
UK MHRA-licensed routes that dispense these medicines
The following directories list UK clinics and pharmacies that operate under General Pharmaceutical Council registration and CQC regulation where applicable. They are listed for reference only. Inclusion is not an endorsement of any medicine for any reader. Cross-reference: tirzepatide and semaglutide editorial commentary.
- · UK clinic directory: clinician-led services operating under GPhC and (where applicable) CQC oversight.
- · UK pharmacy directory: GPhC-registered online pharmacies operating under the Human Medicines Regulations 2012.
- · NHS access notes: editorial summary of the NICE-defined NHS pathway.
This page is editorial commentary on the published clinical literature and the UK regulatory record. It is not medical advice and it does not recommend any medicine to any individual. Semaglutide and liraglutide are prescription-only medicines. The decision about whether either medicine is appropriate, and at what dose, is between a patient and a UK-licensed prescriber, who will refer to the current SmPC, the patient's clinical history, and the relevant NICE appraisal. Always read the patient information leaflet supplied with any prescribed medicine.