Liraglutide

Liraglutide was the first GLP-1 widely prescribed for weight loss, but in everyday practice it has been overtaken by the newer weekly GLP-1s. Semaglutide (Ozempic/Wegovy) and the dual GIP/GLP-1 agonist tirzepatide (Mounjaro/Zepbound) typically produce larger weight loss and only require one injection a week. Liraglutide remains useful where a shorter-acting daily option matters, and is the only GLP-1 currently licensed for adolescents aged 12–17 with obesity.

The evidence base is robust. In type 2 diabetes, the LEAD programme (LEAD-1 through LEAD-6, 2009–2010) established glycaemic efficacy versus placebo, sulfonylureas, glargine and exenatide. LEADER (Marso et al., NEJM 2016) randomised 9,340 patients with type 2 diabetes and high cardiovascular risk and showed a 13% relative reduction in major adverse cardiovascular events over a median 3.8 years, the first cardiovascular outcomes trial to show MACE reduction with a GLP-1. For weight loss, the SCALE programme is the headline evidence: SCALE Obesity and Prediabetes (Pi-Sunyer et al., NEJM 2015) reported a mean 8.0% body-weight reduction at 56 weeks on liraglutide 3.0 mg versus 2.6% on placebo, with 63% of treated participants losing ≥5%. SCALE Diabetes (Davies et al., JAMA 2015) showed 6.0% versus 2.0% in adults with T2D. The honest caveats: trials are sponsor-run (Novo Nordisk), and head-to-head against semaglutide (STEP-8) and tirzepatide (SURMOUNT-1) showed substantially larger weight loss with the newer agents, semaglutide 2.4 mg produced roughly twice the body-weight reduction of liraglutide 3.0 mg in STEP-8. So: clearly effective, clearly approved, but no longer the first-line choice in most weight-loss contexts.

For information only, this is a prescription medicine and dosing must be set by a clinician, not by reading a webpage. Victoza is given as a once-daily subcutaneous injection starting at 0.6 mg for one week, then 1.2 mg, with an optional escalation to 1.8 mg based on glycaemic response. Saxenda follows a 5-week escalation from 0.6 mg daily up to a 3.0 mg daily maintenance dose. The slow escalation exists specifically to reduce gastrointestinal side effects. Self-dosing from unregulated suppliers is unsafe: the products are unverified, the escalation matters for tolerability, and prescriber oversight catches the contraindications below.

The commonest side effects are gastrointestinal, nausea, vomiting, diarrhoea, constipation, abdominal pain, typically worst during dose escalation and easing over time. Most are mild to moderate; a minority of patients discontinue because of them. More serious risks on the label include pancreatitis (rare), gallbladder disease (the SCALE programme showed an increased rate of cholelithiasis at the 3.0 mg dose), and acute kidney injury, usually mediated by dehydration from vomiting. The FDA label carries a boxed warning for thyroid C-cell tumours based on rodent data; whether this translates to humans is unresolved, but the medicine is contraindicated in anyone with a personal or family history of medullary thyroid carcinoma or MEN 2 syndrome. Not for use in pregnancy or breastfeeding. Injection-site reactions are common. The shorter half-life means that, unlike semaglutide, side effects resolve within a few days of stopping.