A new class of weight loss medications has arrived in Australia, and it is generating significant interest from both the medical community and the general public. GLP-1 receptor agonists — originally developed for type 2 diabetes — are now approved by the Therapeutic Goods Administration (TGA) for the treatment of obesity. Here is what you need to know about them.
What Is GLP-1?
GLP-1 stands for glucagon-like peptide-1. It is a hormone produced naturally in the small intestine in response to food intake. GLP-1 performs several functions: it stimulates insulin secretion, suppresses glucagon release (which lowers blood sugar), slows gastric emptying, and signals satiety to the brain.
In short, GLP-1 tells your body that you have eaten enough and helps regulate how your body processes that food. GLP-1 receptor agonists are synthetic medications that mimic this hormone at much higher concentrations than the body produces on its own, amplifying the appetite-reducing and metabolic effects.
Which GLP-1 Medications Are Available in Australia?
There are currently three GLP-1 receptor agonists approved and available in Australia for weight management or diabetes, each with different active ingredients, dosing schedules, and TGA indications.
Semaglutide (Wegovy) — Approved by the TGA specifically for chronic weight management. Administered as a once-weekly subcutaneous injection. The dose is escalated over 16 weeks, starting at 0.25mg and increasing to a maintenance dose of 2.4mg. Clinical trials (the STEP programme) demonstrated average weight loss of approximately 15% of body weight over 68 weeks. Wegovy became available in Australia in 2024 and is currently not listed on the PBS for obesity, meaning patients pay the full cost out of pocket.
Semaglutide (Ozempic) — The same active ingredient as Wegovy but at a lower maximum dose (1mg or 2mg) and TGA-approved for type 2 diabetes, not weight management. Ozempic is PBS-listed for eligible diabetes patients. It has been widely prescribed off-label for weight loss, which has contributed to supply shortages. The TGA and medical bodies have discouraged off-label prescribing due to the impact on availability for diabetes patients.
Liraglutide (Saxenda) — An older GLP-1 receptor agonist approved for weight management. Administered as a daily subcutaneous injection with doses escalated over five weeks to a maintenance dose of 3.0mg. Clinical trials showed average weight loss of 5–10% of body weight. Saxenda has been available in Australia longer than Wegovy and is not PBS-listed for obesity. It requires daily dosing compared to Wegovy’s weekly injection, which is a practical consideration for many patients.
Tirzepatide (Mounjaro) — Technically a dual GIP/GLP-1 receptor agonist, meaning it targets two incretin hormones rather than one. TGA-approved for type 2 diabetes and under review for an obesity indication. Administered as a once-weekly injection. Clinical trials (SURMOUNT) showed weight loss of up to 22.5% of body weight at the highest dose — the most significant results of any medication in this class to date. Mounjaro is PBS-listed for type 2 diabetes but not yet for weight management.
How Are They Prescribed?
All GLP-1 medications in Australia are prescription-only (Schedule 4). A patient must be assessed by an authorised prescriber — a GP, endocrinologist, or telehealth doctor — who evaluates their BMI, medical history, current medications, and weight-related comorbidities.
For weight management indications, prescribing guidelines generally require a BMI of 30 or above, or 27 or above with at least one comorbidity such as type-2 diabetes, hypertension, dyslipidaemia, or obstructive sleep apnoea.
Once a prescription is issued, the medication is dispensed by a registered pharmacy. With the growth of telehealth in Australia, an increasing number of patients are consulting prescribers online and having medications dispensed through registered online pharmacies. Australians searching for wegovy online, for example, will find TGA-compliant pharmacy services that dispense with pharmacist oversight and deliver directly.
Known Side Effects
The most common side effects across all GLP-1 medications are gastrointestinal: nausea, vomiting, diarrhoea, and constipation. These are most pronounced during dose escalation and tend to diminish over time. Prescribers manage this by increasing doses gradually rather than starting at the full therapeutic dose.
Less common but more serious reported effects include pancreatitis, gallbladder disease, and potential thyroid C-cell tumours (observed in animal studies with semaglutide, though not confirmed in humans). GLP-1 medications are contraindicated in patients with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2.
Cost in Australia
Cost remains a significant barrier. Without PBS subsidy for obesity indications, patients pay full price:
- Wegovy: approximately $320–$450 per month
- Saxenda: approximately $390–$440 per month
- Mounjaro (off-label for weight loss): approximately $280–$750 per month depending on dose
PBS listing for obesity indications is an ongoing discussion, with health economists and advocacy groups pushing for subsidised access given the long-term healthcare costs associated with untreated obesity.
What the Research Shows
GLP-1 medications represent a meaningful advance, but they are not without limitations. Weight regain after discontinuation is well documented — the STEP 1 extension trial found that participants regained approximately two-thirds of lost weight within a year of stopping semaglutide. This suggests that for many patients, GLP-1 treatment may need to be long-term, which has further cost and supply implications.
The medications are most effective when combined with dietary modification, physical activity, and behavioural support. They are a medical tool, not a standalone solution, and require ongoing supervision from a qualified healthcare provider.
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