For Kansasin Darwan, a 48-year-old resident of Bajool in central Queensland, the promise of a weight-loss injection felt like a medical breakthrough.
Instead, she says, it left her struggling to function. After failing to meet the clinical criteria for a prescription through her Australian GP, Darwan turned to a beauty clinic in Bangkok during a holiday, purchasing an injectable medicine branded as Mounjaro.
The result was a harrowing decline in her health: dizziness, nausea, and a total loss of appetite that left her unable to drive or sleep. She is one of many Australians caught in the shadow of a surging, often unregulated, weight-loss drug market.
The Rise of Informal Supply Chains
The demand for GLP-1 receptor agonists has exploded, with data from the University of New South Wales (UNSW) revealing that total sales of these medicines climbed from approximately 58,000 in May 2020 to 500,000 by April 2025. As of November 2025, roughly 18 out of every 1,000 Australians were using these drugs regularly. This rapid expansion has outpaced the formal medical system, pushing many consumers toward social media sellers and overseas beauty clinics.
SBS Thai reported that weight-loss medicines are being advertised without prescriptions in Australian community groups on Facebook. In one instance, an investigator posing as a buyer was offered a 5mg vial of Mounjaro for $750—nearly double the $375 to $415 price range found at regulated Australian pharmacies. The Therapeutic Goods Administration (TGA) has issued repeated safety advisories, noting that importing GLP-1 medicines for commercial use without authorization is illegal.
The regulator’s concerns extend beyond imported branded drugs to the proliferation of unapproved peptides. Earlier in August 2026, the TGA, assisted by NSW Police, seized over $120,000 worth of unapproved products from two properties in New South Wales.
Among the confiscated items were products labeled as “retatrutide,” an experimental drug that acts on three distinct hormonal pathways. Despite having no Australian approval for sale, retatrutide has appeared in local outlets, including a Thai grocery store in Geelong, where it was offered for $300 per 10mg vial.
Medical Risks and Mental Health Nuance
The danger is not merely hypothetical. In June 2026, Victoria’s Department of Health confirmed it had been notified of six cases of acute liver injury linked to products labeled as retatrutide. Trevor Steward, an associate professor of psychology at the University of Melbourne, is currently leading a clinical trial to examine how GLP-1 drugs interact with the neurobiological functions of individuals with eating disorders.
It’s not about aesthetics. It’s not about achieving a certain number on a scale. It’s about someone’s mental and physical wellbeing. “It's about someone's mental and physical wellbeing. And that's something that needs to be considered holistically with a doctor involved,” Trevor Steward, associate professor of psychology at the University of Melbourne, told SBS Thai.
Steward highlights a critical gap in the public understanding of these medications: the potential for rebound effects. If a patient stops treatment and the weight returns, the associated “food noise”—the persistent preoccupation with eating—may also resurface, potentially triggering old patterns of behavior.
Regulatory Challenges in a Digital Marketplace
The TGA continues to warn that products purchased online often fail to meet basic safety standards. Testing conducted in March 2026 revealed that several imported products labeled as GLP-1 analogues contained none of the advertised active ingredients. This leaves consumers in a precarious position, often unaware of whether they are injecting a legitimate, albeit unapproved, substance or an entirely inert mixture.
While private, non-subsidized access to GLP-1s accounted for 43.8 per cent of total usage by April 2025, the shift toward informal channels remains a primary concern for public health officials.
For patients like Darwan, the experience served as a stark lesson in the limitations of bypassing the established medical system. She has since ceased using the injections, noting, “My mood was depressing. I suffered from energy loss. I will not use [GLP-1 drugs] again.”
