Retatrutide: The dangerous black market weight-loss drug causing concern

A man in his 30s has died after taking an unapproved weight-loss drug known as retatrutide, with dozens more reporting serious side effects. The drug, still in clinical trials, is fueling a dangerous black market.

The UK has seen a troubling rise in the use of unapproved weight-loss drugs, with a recent fatality and numerous serious side effects reported. The drug in question, retatrutide often referred to as the ‘Godzilla’ of weight-loss jabs, has not been approved for medicinal use anywhere in the world.

Despite this, its popularity has surged, leading to a booming black market where patients risk obtaining fake or contaminated versions.

Retatrutide, manufactured by Eli Lilly is currently undergoing clinical trials and is not legally available outside of these settings. The drug has shown promise in helping people lose up to a third of their body weight in less than a year, positioning it as a potential successor to popular weight-loss treatments like Mounjaro and Wegovy.

However, its unapproved status means that any use outside of clinical trials is illegal and potentially dangerous.

Rise in reported side effects and fatalities

The Medicines and Healthcare products Regulatory Agency (MHRA) has recorded 77 reports of suspected side effects linked to retatrutide since 2026.

These reports do not definitively prove that the drug caused the adverse reactions but indicate that the patients were taking the drug at the time. In 2026, there were 14 reports including 12 serious and 2 non-serious cases. Tragically, one of these reports involved the death of a man in his 30s.

So far in 2026, the number of reports has increased by 350% with 48 serious and 15 non-serious suspected adverse reactions recorded. No deaths have been reported this year, but the rising number of incidents is a cause for concern. The most common side effects reported include gastrointestinal symptoms such as stomach pain, nausea, diarrhea, vomiting, constipation, and bloating. Additionally, there have been 8 suspected hepatobiliary reactions which affect the liver, gallbladder, pancreas, and bile ducts.

The dangers of the black market

Experts warn that the soaring demand for weight-loss jabs has fueled a dangerous black market. Patients seeking retatrutide may be obtaining fake or contaminated versions of the drug from unlicensed sellers. Naveed Sattar professor of cardiometabolic medicine at the University of Glasgow emphasized the risks: ‘No one in the UK should be on a drug that is not licensed or has not been approved by the MHRA. People need to be very wary of something that’s been sold to them called retatrutide because it is likely not retatrutide. They could be injecting into their body any substance that could potentially cause them harm.’

The MHRA’s Yellow Card scheme allows patients and doctors to log concerning side effects. The data shows that women accounted for the majority of reports, with 52 submitted by female patients compared to 23 by men. In cases where age was recorded, patients in their 30s accounted for the largest group, followed by those in their 40s, 20s, and 10 to 19-year-olds.

Global concerns and health warnings

The dangers of unapproved retatrutide are not limited to the UK. Health officials in Australia recently revealed that six people had been hospitalized with severe liver damage after taking unlicensed doses of the drug. One user, Megan Hancocks 32, was rushed to hospital with acute liver failure within a week of using off-market retatrutide. Her symptoms included severe jaundice, nausea, vomiting, extreme fatigue, stomach swelling, and debilitating constipation. Doctors treated her for a month, and her condition stabilized before a liver transplant was required.

The MHRA has also received one report of an eye disorder linked to the drug. It is believed that some people starting approved weight-loss jabs can experience temporary changes in vision as blood sugar levels adjust. The MHRA stresses the importance of sourcing medicines from registered healthcare professionals and legitimate pharmacies to avoid the risks associated with unregulated sources.

Eli Lilly has issued a warning about the potential dangers of fake medicines, stating that retatrutide is an investigational molecule legally available only to participants in their clinical trials. The company continues to warn the public about the risks of taking unapproved medications.

As the demand for weight-loss drugs continues to rise, so does the need for vigilance and education about the dangers of unapproved medications. The case of retatrutide serves as a stark reminder of the risks associated with seeking quick fixes for weight loss without proper medical supervision.