Body-building and fitness companies are selling supplements which may contain synthetic amphetamines and stimulants that have never been tested on humans, in some cases bypassing rules that require approval with the NSW Food Authority.
Anti-doping experts say athletes using the supplements are in danger of inadvertently breaching doping laws, to say nothing of the potential health risks posed by taking the drugs.
But companies selling the body-improvement and muscle-building products are under no obligation to list them with Australia's drug regulator, with many of the products imported as "food" or simply ignoring the laws altogether.
The Department of Health says it is aware of concerns about one of the substances, called Acacia rigidula, and people taking it should be aware, that, in the absence of evidence of safety, it could pose a risk to human health.
Last week US researchers published the results of a study that found more than half the supplements that contained an ingredient called Acacia rigidula actually contained a synthetic amphetamine called beta-methylphenylethylamine, which has never been proven safe in humans.
The paper, published in the journal Drug Testing and Analysis, warned doctors should be on the look-out for patients suffering from toxicity from supplement and weight-loss products, while athletes should be aware they might be in breach of international doping laws if they take them.
A spokeswoman for the federal department of health said Acacia rigidula had recently been classified as a "novel food", meaning companies that sold it must get pre-approval from state and territory authorities, which were responsible for policing food.
The NSW Food Authority on Wednesday night confirmed no companies had been approved to sell the product despite companies such as Mr Supplement advertising products that contain it.
Greg Shaw, a senior sports dietician from the Australian Institute of Sport, said Acacia rigidula appeared to be part of a trend of supplement producers finding a very small, almost trace dose of an ingredient in a plant and then putting that plant in a product that, if tested, would show very large doses of stimulants.
"The use of botanical names for chemical stimulants is a big problem in this area," he said. "There have been arguments about whether what they have been finding are amounts that could be found in the botanical products that were just being concentrated in the supplements, or whether these companies were actually adding them."
He said a large number of breaches of doping rules currently being seen were related to athletes who had taken stimulants in supplements, but often athletes did not realise what they were taking was banned because it was disguised by botanical names and carried in products that appeared to have been legitimately imported and sold either online or in-store.
In its last annual report the Australian Sports Anti-Doping Authority warned that more than half of all the doping violations in 2013-14 were related to stimulants.
"We are seeing pharmaceutical stimulants that aren't even approved for human use yet turning up in supplements," he said. "Not only is there the doping risk … there's also the risk it is going to affect their performance, recovery, heart rate, a whole range of things."
"There are also the long-term effects, particularly for adolescents who have easy access to these things – we have no idea what the risks could be."
In October Western Australian doctors reported in the British Medical Journal that they had treated a patient with heart problems that were eventually found to have been brought on by muscle-building supplements.
The spokeswoman for the department of health said generally sports supplements were not considered to be therapeutic goods, but in this case it was aware of concerns regarding the Acacia rigidula products.
"The Therapeutic Goods Administration is aware of the international concerns over beta-methylphenylethylamine [and] is currently reviewing the available information to determine what, if any, action is required in Australia," she said.
She said the products were sold as "sports food" if they were specifically formulated to assist sports people in achieving specific nutritional or performance goals.
Ken Harvey, an adjunct associate professor in the school of public health at Monash University, said the case illustrated huge gaps left in the regulation of products that tread the line between food and medicine.
"If it is going down the path of being labelled a food, it shouldn't be making health claims," he said. "It is a problem that there is no central body dealing with these complaints, and it comes down to state and federal food bodies, which are more interested, perhaps reasonably, in policing food poisoning cases in local restraints and things like that."
"If it is making therapeutic claims it should fall under the auspices of the Therapeutic Goods Administration."
Mr Supplement did not respond to requests for comment.
