GLP-1 medicines have grown in barely five years into Australia's largest single class of medicines, by a margin, and their rise could be reshaping the broader prescription medicines market.
Intelligence firm Nostradata, which collects data from more than 90 per cent of Australian community pharmacies, reports that approximately 1.6 million people have accessed a GLP-1 medicine privately in the past 12 months, building a market with a retrospective annual value of around $2.3 billion.
BioPharmaDispatch understands that the most recent month-to-month utilisation puts the current annualised private market spend at around $3 billion.
That is the private GLP-1 medicines market, excluding a PBS listing for diabetes.
That growth rate and market size have no precedent.
Hepatitis C antivirals were listed on the PBS in 2016. It was the largest single listing in PBS history. Initial spending was substantial, reaching over $1 billion in the first four months. By the end of 2016, spending on the therapies had topped $2 billion. However, the therapies were short-duration cures, and manufacturers repaid most of the spend through rebates.
Compare that to GLP-1 medicines for weight loss.
A UNSW study led by Associate Professor Michael Falster found monthly GLP-1 sales rose from 58,000 units in May 2020 to 500,000 in April 2025. In that study, of the more than 6 million units dispensed through April 2025, 47.8 per cent were accessed privately.
IQVIA estimated the entire non-PBS retail prescription market at $1.6 billion in 2024, up from $0.7 billion in 2019.
The GLP-1 market is more than three times the cost of the most expensive PBS medicine in 2024–25 and larger than every PBS therapeutic group except cancer and immunomodulating medicines, which cost $7.2 billion in 2023–24, though that figure does not account for manufacturer rebates.
Novo Nordisk's OZEMPIC (semaglutide) is PBS-listed for type 2 diabetes, but no GLP-1 is subsidised for weight loss. Eli Lilly's MOUNJARO (tirzepatide) is not on the PBS after the company declined to proceed with a type 2 diabetes listing in April this year.
The private spending has shifted the balance between public and private medicines.
The Australian pharmaceutical market is now a tale of two systems.
The private share of the retail prescription market rose from 9 per cent in 2019 to 15 per cent in 2024, according to IQVIA, with the non-PBS market growing by 20 per cent a year against tepid growth for the PBS. The category containing weight loss medicines grew at 39 per cent a year to account for around one third of private sales. Outside weight loss medicines and medicinal cannabis, private growth has been reported in hormone therapies and contraceptives.
Yet this reporting predates the latest surge in private use of GLP-1 medicines for weight loss. Another surge may follow the pending approval of oral GLP-1 medicines.
These medicines are also displacing other obesity treatments. Over the four years to April 2026, IQVIA found sales of over-the-counter weight-management products halved to 2.6 million units and sales of older obesity medicines fell from 779,000 units to 556,000. Medicare-funded bariatric surgery services fell from 24,200 to 11,600.
The private market growth has come as public investment in new medicines has stalled.
Confidential rebates paid by sponsors rose from 20 per cent of total PBS expenditure in 2017–18 to 35 per cent in 2024–25, Medicines Australia reports, while net investment in innovative medicines fell by 3 per cent in real terms over the three years to 2024–25.
As a result, Australia's total spending on prescription medicines is growing faster than PBS statistics show, and because most private sales sit outside government reporting, its full scale is increasingly hard to assess.
The market is also set to become far more crowded and competitive.
IQVIA estimates there are over 193 assets in development as of October 2025, up from 181 in May 2025. Innovation is accelerating through new mechanisms of action and routes of administration, such as orals and ultra-long-acting injectables.
