The Therapeutic Goods Administration (TGA) has warned Australians that counterfeit semaglutide is being illegally imported into the country.
The diabetes medication, also known as Ozempic, has seen massive demand in recent months after it was linked to weight loss by some major celebrities.
TGA warn the importation of prescription-only medicines without a valid prescription is illegal even if only for personal use.
Which products should be avoided?
TGA laboratory testing confirmed two products, available in Australia, did not contain the active semaglutide ingredients as labelled.
The products were Global Health Pharmaceuticals and Therapeutics branded Semaglutide 5mg vial and Peptides Lab branded Semaglutide 10mg vial.

"These results serve as a warning to consumers to avoid buying semaglutide products from unverified online sellers as they may not contain the active ingredient," TGA said.
Counterfeit products may also contain other undeclared and hazardous ingredients that could cause serious risk to the health and safety of consumers, it said.
They also may not meet manufacturing quality and safety standards and have unknown contaminants.
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What should concerned customers do?
Those with the counterfeit drug should stop taking the product immediately and take any remaining product to your local pharmacy for safe disposal, TGA said.
"Speak to your healthcare provider if you have concerns because of your use of this product," it said.

TGA recommends extreme caution when purchasing medicines from unknown overseas websites.
It approved the temporary supply of some overseas semaglutides that were legal to purchase during the shortage driven by the massive boom in popularity.
Customers can check if their overseas product has been approved for use via the TGA's Section 19A approvals database.
But these products must be supplied through Australian pharmacies with a valid prescription, TGA said.