Summary

Liraglutide is a glucagon-like peptide-1 (GLP-1) receptor agonist originally developed for type 2 diabetes and later approved for weight management. As a close predecessor to semaglutide, it established the clinical proof-of-concept for GLP-1-based obesity treatment. It is a prescription-only medicine in the UK, not a research chemical.

Mechanism

GLP-1 receptor agonist. Liraglutide mimics the endogenous incretin hormone GLP-1, binding to and activating the GLP-1 receptor on pancreatic beta cells (stimulating glucose-dependent insulin secretion), alpha cells (suppressing glucagon), and the central nervous system (reducing appetite and increasing satiety). A C16 fatty-acid side chain enables albumin binding, extending the half-life to ~13 hours — approximately 11 hours longer than native GLP-1 [1].

Evidence base

Strong evidence base. The LEAD Phase 3 programme (type 2 diabetes, n>4,000) demonstrated HbA1c reductions of 0.8–1.5 percentage points and weight loss of 1.0–3.2 kg [3]. The SCALE Obesity and Prediabetes trial (n=3,731) showed 8.4% mean weight loss at 56 weeks with liraglutide 3.0 mg versus 2.8% with placebo [4]. The LEADER cardiovascular outcomes trial (n=9,340) demonstrated a 13% reduction in major adverse cardiovascular events over 3.8 years [5]. Multiple meta-analyses and real-world studies confirm these findings.

Protocols

Licensed dosing (informational, not medical advice):

Type 2 diabetes (Victoza): Start 0.6 mg SC daily x1 week → 1.2 mg daily. May increase to 1.8 mg daily [2].

Weight management (Saxenda): Gradual titration over 5 weeks: 0.6 → 1.2 → 1.8 → 2.4 → 3.0 mg SC daily. Maintenance: 3.0 mg daily [4].

Route: Subcutaneous (abdomen, thigh, or upper arm) Frequency: Once daily, any consistent time Titration rationale: Minimises gastrointestinal side effects (nausea, vomiting) during initiation [4].

Liraglutide is a licensed prescription-only medicine (POM) in the UK, regulated by the MHRA. It is NOT a research chemical. Victoza is licensed for type 2 diabetes; Saxenda is licensed for weight management (BMI ≥30, or ≥27 with comorbidities). Supply without a prescription is illegal. The MHRA has issued warnings about unlicensed weight-loss injectables sold online [7].

Vendor notes

Liraglutide is a prescription-only medicine in the UK and cannot be legally sold by research peptide vendors. It should only be obtained from a registered pharmacy with a valid NHS or private prescription. Any non-pharmacy source offering liraglutide is operating outside UK law.

References

  1. Knudsen LB, Lau J. The discovery and development of liraglutide and semaglutide. Front Endocrinol. 2019;10:155. doi:10.3389/fendo.2019.00155
  2. Novo Nordisk. Victoza (liraglutide) Summary of Product Characteristics. MHRA. Available at: https://www.medicines.org.uk/emc/product/3197
  3. Garber A, Henry R, Ratner R, et al. Liraglutide versus glimepiride monotherapy for type 2 diabetes (LEAD-3 Mono): a randomised, 52-week, phase III, double-blind, parallel-treatment trial. Lancet. 2009;373(9662):473-481. doi:10.1016/S0140-6736(08)61246-5
  4. Pi-Sunyer X, Astrup A, Fujioka K, et al. A randomized, controlled trial of 3.0 mg of liraglutide in weight management. N Engl J Med. 2015;373(1):11-22. doi:10.1056/NEJMoa1411892
  5. Marso SP, Daniels GH, Brown-Frandsen K, et al. Liraglutide and cardiovascular outcomes in type 2 diabetes. N Engl J Med. 2016;375(4):311-322. doi:10.1056/NEJMoa1603827
  6. Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide once weekly for the treatment of obesity. N Engl J Med. 2022;387(3):205-216. doi:10.1056/NEJMoa2206038
  7. MHRA. Warning over unlicensed weight-loss injectables. UK Government. 2023. Available at: https://www.gov.uk/government/news/mhra-issues-warning-over-unlicensed-weight-loss-injectables