A Sydney-based model and cosmetic doctor has been referred to health authorities by the anti-doping watchdog after he enthusiastically endorsed muscle-building peptides.
In an article published in Executive Style in November Dr Django Nathan said "quite a few doctors I know are using [peptides] because they have so many beneficial effects and so few side effects".
The peptides he was using had not been rigorously tested in humans, he said, but said the risks were low.
He also suggested readers get their peptide prescriptions online. Fairfax Media found many Australian websites allow customers to apply for a peptide prescription from a doctor by simply filling out a five-minute questionnaire.
ASADA, which is working to crack down on doctors who prescribe peptides, is furious. The Australian Sports Anti-doping Authority issued a media release slamming the article and referred Dr Nathan to health authorities.
"It is irresponsible for any person in a position of authority to downplay or disregard the risks associated with these substances," ASADA CEO David Sharpe said.
"When it comes to the abuse of performance-enhancing drugs, the risks are real and extremely dangerous. These include things like blood clots, liver damage, stroke, kidney damage, brain impairment and even death."
The agency declined to identify which authority Dr Nathan had been reported to, or the exact reasons for which he had been reported.
In NSW, where Dr Nathan is registered, complaints about and investigations of medical practitioners are handled by two authorities - the Health Care Complaints Commission and the Medical Council of NSW.
They have the power to suspend a doctor's licence or impose conditions on their registration.
Both said they were legally prevented from confirming if a complaint had been made.
Dr Nathan said on Thursday that he was unaware ASADA had made a complaint against him, and that he had done nothing wrong.
"I don't prescribe peptides, I just use them myself. I don't give peptides to patients. I think they are a very useful form of molecules. I have not seen much harm done by them.
"I don't think [ASADA] have a very good understanding of what peptides are."
Dr Nathan said he had been prescribed peptides by a friend and doctor who also part-owned a peptide company.
"I'm using it mostly to save time. I'm working flat out all the time. If I can stay healthy and potentially be able to do things and sleep better, those are all advantages that go with certain peptides.
"I'm using them for myself, and as a free, well-educated person I have looked at the information, all the research, and I'm choosing to take them."
He told Fairfax he was an educated user of peptides, but not an expert.
Dr Nathan received his bachelors in medicine and surgery from the University of Sydney in 2015. He worked as a model while studying, according to his personal website.
"Dr Nathan uses a combination of anti-wrinkle treatment and dermal filler to stop the clock, and often turn it backwards, bringing beauty and brightness into a face," the website says.
He practises in Bondi, Surry Hills, Milperra, Parramatta, San Souci, Orange and Brisbane, the website says.
There are a wide range of peptides available for sale in Australia online. Because they can cause significant changes to the body, including the pancreas, ovaries, testes and thyroid, many require a prescription from a doctor before they can be legally supplied.
Peptides are legal to use with a prescription even if they haven't been tested for safety or approved for use by Australia's medical regulators.
Several Australian websites that sell peptides also link customers to doctors who can write those prescriptions. One website advises customers to place an order for their preferred peptide; the website then sends out a five-minute medical questionnaire.
A doctor will review the questionnaire and then, if authorised, write a prescription and send it to the site's compounding pharmacy. Health authorities are seriously worried about the practice and are investigating doctors who prescribe peptides across Australia.
Fairfax Media is the publisher of The Age and Executive Style.