Saxenda vs Wegovy in Australia

STEP 8, published in JAMA in January 2022, is the only trial that randomised the two medicines against each other. Novo Nordisk's May 2025 letter announcing Saxenda's withdrawal cited it as the reason.

The trial enrolled 338 adults with a BMI of 30 or more, or 27 or more with a weight-related condition, and no diabetes, at 19 sites in the United States: semaglutide 2.4 mg once a week (126 people), liraglutide 3.0 mg once a day (127) or placebo (85) for 68 weeks, with diet and exercise counselling. Mean age 49, 78% women, mean weight 104.5 kg, mean BMI 37.5.

Both are GLP-1 receptor agonists with the same family of side effects. Liraglutide's half-life is about 13 hours and it is injected daily; semaglutide's is about 165 hours and it is injected weekly. The Saxenda Product Information (revised 26 June 2026) remains the Australian reference for liraglutide 3 mg; the generic pens carry the same indication, dose and stopping rule.

What to expect in the first months: Nausea, diarrhoea, constipation and vomiting are the common effects and cluster around each dose increase. In Saxenda's pooled trials 39.3% had nausea against 13.8% on placebo, and 9.8% stopped because of side effects against 4.3%. In Wegovy's pooled trials 38.3% had nausea against 14.0%, and 4.3% stopped because of gut effects. The Saxenda document says to consider stopping if a dose step is not tolerated for two consecutive weeks; the Wegovy document says to consider delaying the next step until symptoms improve, and allows 1.7 mg as a maintenance dose if 2.4 mg is not tolerated.

Symptoms that need urgent medical attention, listed in both Consumer Medicine Information leaflets: severe and persistent pain in the stomach area, possibly reaching to the back (pancreatitis); skin rash over a large area, wheezing, swelling of the face, lips or tongue (severe allergic reaction); sudden loss of vision (NAION); and severe constipation with stomach pain, bloating and vomiting (bowel obstruction). The Saxenda leaflet also lists gallbladder problems (upper right abdominal pain, yellowing of the skin and eyes), reduced kidney function and new or worsening depression or sudden mood changes. Both say vomiting or diarrhoea can cause dehydration and kidney problems, and to keep drinking fluids.

Both are Schedule 4 prescription-only medicines. Compounded versions have been illegal to make or supply in Australia since 1 October 2024. In March 2026 the TGA reported that laboratory tests of imported unregistered products labelled as GLP-1 found they contained none.

A GP, a specialist or a nurse practitioner (within their scope of practice; rules vary by state and territory) can prescribe. Both Product Information documents set the same starting criteria: a BMI of 30 or more, or 27 to 30 with at least one weight-related condition such as prediabetes or type 2 diabetes, high blood pressure, high cholesterol or sleep apnoea, alongside a reduced-energy diet and more physical activity. The liraglutide document adds a stopping rule: less than 5% of starting weight lost after 12 weeks on 3.0 mg, discontinue. In its trials 67.5% met that mark and averaged 11.2% loss at one year; the rest averaged 3.8%.

A Saxenda script cannot be filled with Saxenda. Whether a pharmacist can dispense a generic liraglutide brand on it was not confirmed for this page. Only ARX-Liraglutide was found on a retailer's shelf, and Chemist Warehouse sells it in store only. Telehealth programs (Juniper, Hims, Moshy, Mosh, Youly, hub.health, InstantScripts and others) decide the medicine and dose at the consultation, not by the bundle price.

On the evidence Wegovy is the more effective medicine: 9.4 percentage points more weight loss than liraglutide in STEP 8, the same rate of gut side effects and a quarter of the side-effect dropouts. Liraglutide is the cheaper one at maintenance ($209.00 against $369.99 a month at Chemist Warehouse, 9 November 2026) and the one injected daily. Novo Nordisk has withdrawn its own liraglutide brand in favour of Wegovy; the generic remains. A prescriber weighs the following.

No Australian guideline covers moving from Saxenda or generic liraglutide to Wegovy. Novo Nordisk's May 2025 letter encouraged prescribers "to discuss alternative treatment options with patients currently using Saxenda, including Wegovy 2.4 mg"; it gives no dosing guidance, and no patient-facing Novo Nordisk notice was found. The RACGP repeated the advice to GPs on 11 December 2025. Neither Product Information mentions a switch. Both say the medicine must not be used with another GLP-1 agonist, so the two are not overlapped.

There is no dose equivalence between daily liraglutide and weekly semaglutide. The Wegovy document gives one starting dose, 0.25 mg, with steps at weeks 5, 9, 13 and 17 to reach 2.4 mg, and no shortcut for people arriving from liraglutide, so a switch means repeating an escalation period and its side effects. At least one Australian telehealth site describes a washout or step-down protocol; it cites no source and neither Product Information contains one. British pharmacists in the Pharmaceutical Journal (2026), writing on switches between tirzepatide and semaglutide rather than from liraglutide, describe, in the absence of official guidance, either a one to two week washout where side effects were a problem or a same-day switch, then the new medicine at its starting dose. That is practitioner practice for a different pair, not a guideline. The reverse move, Wegovy to generic liraglutide, has the same absence of guidance; liraglutide starts at 0.6 mg daily and rises by 0.6 mg each week to 3.0 mg.

In SCALE, people switched from liraglutide to placebo after 56 weeks regained 2.9% of their body weight within 12 weeks. A year after stopping semaglutide in the STEP 1 extension (an exploratory subset of 327 participants), people had regained two thirds of what they lost. A BMJ meta-analysis of 37 studies (January 2026) put average regain after stopping any weight-loss medicine at 0.4 kg a month. Australian Prescriber: "When treatment is stopped, regaining weight is the norm."