We Tested Fake Peptides From the Black Market

We Tested Fake Peptides From the Black Market – Here Are the Findings

Grace Hamann says roughly half of her work now involves testing peptides, according to ABC News.

In summary:

A lab now tests unapproved peptides because social media has caused a big rise in demand for these.

Tests on a popular fake weight‑loss peptide showed that two of three vials contained far more of the drug than the label claimed.

The medicines regulator warned that injecting unapproved peptides is unsafe because they have not yet been tested for human safety in Australia.

Last year this time, chemist Grace Hamann had never heard of black‑market peptides.

Now about half of my job is testing peptides … the growth has been exponential, Hamann said.

In October 2025 we began receiving almost daily testing requests.

As unapproved peptides grew popular online, consumer and wellness‑industry demand pushed her lab, Leeder Analytical, to learn how to test them.

We spent about a month setting up a method so we could test accurately and report results, Hamann said.

Grace Hamann says testing demand for unapproved peptides has surged, ABC News reported.

The lab recently tested three vials of the popular fake weight‑loss peptide retatrutide, taken from black‑market users, at the request of ABC and the University of Queensland.

Retatrutide is still in clinical trials and not approved for human use.

Experts said the results were surprising. One vial had less retatrutide than the label said, while two had much higher amounts.

Leeder Analytical gave ABC a full breakdown of its 2026 black‑market peptide testing results.

The most common request was purity testing of unapproved peptides labeled as retatrutide.

The lab said it tested 18 counterfeit retatrutide samples this year, and only one matched its label claim.

About 30% had higher concentrations, about 30% had lower, and one vial had none of the peptide.

You would expect a seller of an unregulated product to cut costs and include less drug … but seeing almost equal numbers over‑ and under‑100% was surprising, Hamann said.

Testing the fake retatrutide showed two of three vials had much higher concentration than labeled, ABC reported.

Higher, inaccurate unapproved peptide dosing adds extra risk

The testing of the three retatrutide vials was paid for and organized by UQ’s School of Public Health and harm‑reduction group PED Test Australia.

UQ peptide researcher Tim Piatkowski said the tiny sample gave unexpected results because they differed from what we saw in steroid testing.

When we tested many steroids, we saw under‑dosing was very common and overdosing was rare.

Tim Piatkowski of the University of Queensland said he was shocked by the level of overdosing, ABC reported.

Dr Piatkowski and his team reported the results to the Drug and Alcohol Review journal.

Although media often focus on fake or adulterated products, these findings suggest inaccurate dosing alone may be a major risk, the journal article said.

Have you seen injectable peptides yet? They are everywhere on social media and we want to know why people use them and what their experience is like.

Liver‑transplant specialist Marie Sinclair has recently treated Victorian patients with liver failure after they took black‑market peptides labeled as retatrutide.

There is great concern that these unregulated retatrutide vials may not contain exactly what manufacturers claim, Dr Sinclair said.

She said the varying concentration of unapproved peptides is a serious danger to users.

Marie Sinclair has been treating Victorian patients with liver failure after taking black‑market peptides, ABC reported.

Contaminant warnings

But Dr Sinclair worries consumers may seek false safety from purity testing.

All they know from this test is that some retatrutide is in the vial. It does not tell them if other contaminants or drugs are also present, she said.

Dr Sinclair helped test vials from patients who suffered severe liver failure.

We used two labs to do a very thorough analysis of what was in these vials, and even with extensive testing we still do not have the full picture, she said.

A Melbourne lab analysed the weight‑loss peptide retatrutide that was bought from an unregulated internet site.

Hamann said in her experience the peptide usually made up about ten percent of what was in the vials.

So the other ninety percent is unknown and could contain a toxin or something else unsafe, she said.

She said wellness businesses are asking labs to test unapproved peptides so they can give customers a certificate of analysis for reassurance.

Our results do not give the validation sellers want, she said.

Robyn Langham, chief medical advisor at the Therapeutic Goods Administration (TGA), said while test results may show the amount of a substance similar to retatrutide, it cannot be called the same as the peptide in clinical trials.

This is a counterfeit product. Any small change to the molecular structure of a product, especially peptides, makes it a different drug, she said.

Robyn Langham says the black‑market product cannot be considered a replica of the peptide currently in clinical trials.

Counterfeit peptides have not been tested in clinical trials, have not been tested for how they are made, and have not been tested for safety — yet people are injecting them into their bodies.

Professor Langham said finding a peptide is only one factor; there are many other serious risks, such as endotoxins like bacteria and contaminants like heavy metals.

But she added that wrong concentrations also pose a risk.

There can be a risk from the dose alone, she said.

Wellness and anti‑aging clinics are opening across Australia. But do their treatments work and are they safe?

Eli Lilly owns the patent for retatrutide, which is still in clinical trial development.

The company told ABC any version of the drug sold online is unapproved, unverified and simply not worth the risk.

It has also started legal action against several black‑market sellers of products labeled as retatrutide.

In a statement, the company said it wants Australians protected from the risks of unapproved products falsely labeled as retatrutide.

Lilly supports stronger action against the illegal market, including intelligence‑led enforcement, disruption of illicit supply chains and seizure of unlawful products, it said.

The TGA reported that more than 94,500 unapproved peptide products were destroyed this year, working with the Australian Border Force.

Last week the TGA and New South Wales Police seized over $120,000 of illicit peptide and anabolic steroid products from premises linked to a social‑media influencer.

In April authorities seized $2 million worth of steroids and peptides.

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