Saxenda vs Ozempic in Australia

No randomised trial has compared Ozempic at its registered doses (0.5 mg to 2 mg weekly) with liraglutide 3 mg daily. Most pages ranking for this comparison, and earlier versions of this one, set SCALE (liraglutide) against STEP 1 (semaglutide 2.4 mg) as "8% vs 15%". STEP 1 tested the Wegovy dose in people without diabetes.

STEP 8 (JAMA, January 2022) is the one direct trial of semaglutide against liraglutide 3 mg: 338 adults without diabetes at 19 US sites, semaglutide 2.4 mg weekly or liraglutide 3.0 mg daily for 68 weeks, open-label between the active arms. Mean loss was 15.8% on semaglutide and 6.4% on liraglutide, a difference of 9.4 percentage points (95% CI 6.8 to 12.0); pooled placebo lost 1.9%. Gastrointestinal adverse events were almost identical (84.1% vs 82.7%), but 27.6% of the liraglutide group stopped for any reason against 13.5%, and 12.6% stopped for adverse events against 3.2%. Half the liraglutide stops were gut-related and came during dose escalation; the authors point to liraglutide's shorter half-life (13 to 15 hours against 165) and the daily injection. The 2.4 mg arm is above Ozempic's 2 mg ceiling and in a different pen.

STEP 2 (Lancet, 2021) is the only weight-management trial reporting percentage loss at an Ozempic dose: 1,210 adults with type 2 diabetes and a BMI of 27 or more, 68 weeks, semaglutide 2.4 mg, 1.0 mg or placebo. The 1.0 mg arm's 7.0% comes from Novo Nordisk's announcement of 12 June 2020; the paper is paywalled and the abstract reports only the 2.4 mg result. SUSTAIN 10 (2019) set semaglutide 1.0 mg against liraglutide 1.2 mg, the Victoza dose, in 577 people with type 2 diabetes for 30 weeks; discontinuation for adverse events was 11.4% against 6.6%. At less than half the Saxenda dose it says nothing about liraglutide 3 mg. SCALE (NEJM, 2015) is liraglutide 3 mg's placebo-controlled trial: 3,731 adults without diabetes, 56 weeks; 63.2% against 27.1% lost 5% or more.

Both are GLP-1 receptor agonists with the same family of side effects. The Saxenda document is the reference for liraglutide 3 mg; the generic pens carry the same indication text, and their own documents sit behind the TGA's licence page and were not read.

What to expect in the first months: Nausea, diarrhoea, constipation and vomiting cluster around each dose increase. In the pooled Saxenda trials 39.3% had nausea against 13.8% on placebo, 20.9% diarrhoea, 19.4% constipation and 15.7% vomiting; the document says these were mostly mild to moderate and faded within days or weeks. In Ozempic's pooled diabetes trials nausea was 17.0% at 0.5 mg and 19.9% at 1 mg against 6.3% on comparators; diarrhoea 12.2% and 13.3%; vomiting 6.4% and 8.4%. At 2 mg, gastrointestinal disorders were 34.0% against 30.8% at 1 mg.

Symptoms that need urgent attention, in both documents: severe and persistent pain in the stomach or back, with or without vomiting (possible pancreatitis); swelling of the face, mouth or throat or trouble breathing (allergic reaction); and severe vomiting or diarrhoea leading to dehydration, which both link to acute kidney injury. Both carry the class warning the TGA aligned across GLP-1 medicines in December 2025 that suicidal thoughts and behaviour have been reported. The Saxenda document says to stop treatment in anyone who develops them; the Ozempic document says to monitor patients and weigh the benefits and risks. Both warn that food can remain in the stomach under general anaesthesia or deep sedation.

Both are Schedule 4 prescription-only medicines, prescribed by a GP, a specialist or a nurse practitioner (within their scope of practice; rules vary by state and territory). Compounded GLP-1 products have been illegal to make or supply in Australia since 1 October 2024, and in March 2026 the TGA reported that imported unregistered products labelled as GLP-1 contained none.

For liraglutide 3 mg the Product Information sets the criteria: a BMI of 30 or more, or 27 to under 30 with at least one weight-related condition such as prediabetes, type 2 diabetes, high blood pressure, abnormal cholesterol or sleep apnoea, alongside a reduced-energy diet and more physical activity. The dose starts at 0.6 mg a day and rises by 0.6 mg each week to 3 mg by week five. Each new pen is primed once before first use.

Ozempic's registered criteria are for type 2 diabetes, and a weight-loss script is off-label. A TGA statement quoted by the University of Sydney in April 2024 says the regulator cannot prevent doctors from using their clinical judgement to prescribe Ozempic for other conditions; the TGA's advertising page states that advertising Ozempic for weight loss is illegal, including to health professionals. The RACGP's diabetes chair told newsGP in 2022 that off-label prescribing requires documented consent and acknowledgement of the risks, and that other TGA-approved obesity medicines exist. Australian Prescriber's December 2025 review states that Ozempic does not have approval for weight management; Healthdirect lists Ozempic for type 2 diabetes and Wegovy for chronic weight management, and notes that medicines prescribed for weight loss are not covered by Medicare.

The April 2025 AJGP review recommends incretin-based medicines first where type 2 diabetes, cardiovascular disease, sleep apnoea or fatty liver disease is present; it does not rank liraglutide against semaglutide. Telehealth weight-loss programs sell a monthly bundle of consultations, medicine and delivery; the medicine and dose are decided at the consultation, and none of the seven programs checked on 6 October 2026 names the medicine.

The direct trial favoured semaglutide by 9.4 percentage points, with half the dropout rate, at the Wegovy dose of 2.4 mg, which Ozempic does not deliver. At Ozempic's 1 mg dose the only percentage figure is a sponsor-reported 7.0% in people with type 2 diabetes (STEP 2), against 8.0% for liraglutide 3 mg in people without diabetes (SCALE); the populations and durations differ, so the two cannot be ranked.

In Australia the choice turns as much on registration as on efficacy. Liraglutide 3 mg is registered for weight management and prescribed on-label at $209.00 to $250.00 a month. Ozempic is registered for type 2 diabetes; a weight-loss script is off-label and private, and no trial has measured that dose for weight in people without diabetes.

No Australian guideline covers moving from Saxenda or generic liraglutide to Ozempic, or the reverse. Neither Product Information gives a dose conversion, and none exists: 3 mg of daily liraglutide does not equal any weekly dose of semaglutide. Each document gives one starting dose for its own medicine (liraglutide 0.6 mg, Ozempic 0.25 mg), so a switch in either direction means starting at the lowest dose and repeating an escalation period and its side effects.

The Saxenda document states that liraglutide must not be used together with any other GLP-1 receptor agonist, which rules out overlapping the two; the Ozempic document is silent. British pharmacists writing in the Pharmaceutical Journal in 2025, with no official guidance to cite, describe stopping one medicine, waiting one to two weeks if side effects were a problem, and starting the other at its starting dose. That is practitioner practice about Wegovy and Mounjaro, not a guideline.

Novo Nordisk's May 2025 letter asked prescribers to discuss alternatives with Saxenda patients, "including Wegovy 2.4 mg", its own product; it did not mention Ozempic or generic liraglutide. The generic pen is the same molecule at the same dose, and the Healthdirect entry for the Sandoz brand carries the same indication text as Saxenda; no Australian document describes a step for moving between brands.