2 out of 5 TikTok Mounjaro videos are ‘stealthy advertising’

By Amy Reast

Forty percent of TikToks about Mounjaro are "stealthy advertising" - with hidden discount codes - despite it being illegal to promote prescription medicine in the UK.

Millions of people considering the weight-loss shot Mounjaro don't go to doctors for advice - instead, they turn to TikTok, according to a new study.

Research from Brunel University of London into "Mounjaro's TikTok economy" suggests most of what people are watching amounts to hidden advertising.

Advertising a prescription medicine is against the law in the UK.

Researchers analyzed the 100 most-liked Mounjaro videos posted by UK-based creators - and two in five of those videos or the profiles behind them pushed a discount code.

Anyone who used the code saved money on their prescription. The person who shared it earned money too.

The 100 videos analyzed had been watched almost 46 million times, and none of them were presented as ads.

Charlotte Kerner, lead researcher and senior lecturer in Sport Health and Exercise Sciences at Brunel, said: "For me, what stood out was the promotional codes.

"It's a really stealthy way for these companies to advertise their medication."

Access to Mounjaro on the NHS is restricted, so many people turn to private pharmacies without speaking to a qualified primary care doctor.

Those in the videos did not disclose any medical training but appeared to share their own experiences with taking the GLP-1 medication.

Kerner said: "People getting that medication online don't have that clinical support.

"They're looking for social support... people that look like them, that take them and have success.

"It's that element of they're not experts, but they look like me. So, if it works for them, it works for me."

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The videos studied were overwhelmingly upbeat. Two-thirds struck a positive tone, and most leaned on personal testimony rather than evidence.

Just two in a hundred cited any scientific research.

Side effects featured in only a quarter of the videos. Nausea was the most common, followed by hospital admissions, headaches and constipation.

Almost half of the creators said they had bought their Mounjaro through an online pharmacy. Nineteen out of twenty videos offered no disclaimer about the advice being given.

The study also points to 'golden dosing,' a wider trend where some users try to squeeze a fifth dose out of pens meant to be binned after four uses. Doctors warn this risks infection and overdose.

Kerner said: "Social media gives people somewhere to feel safe and comfortable with a decision like this.

"They're seeing real people taking it and talking about what happened to them, rather than one story in the papers. People cling to that."

Co-author Amy Prescott said the personas people build on TikTok are part of what makes the content feel trustworthy.

Prescott said: "You might see a mom of four saying, this is how I've done it.

"Or somebody who struggled at the gym for years saying, I was the same. People recognise themselves in these stories."

TikTok's own rules ban promoting weight-loss products, and prescription-only medicines cannot legally be advertised in the UK.

The Advertising Standards Authority has already warned influencers over weight-loss drug promotion. Kerner's findings suggest that warning is not being heeded.

TikTok can offer genuine comfort to people who feel unsupported by the health system, the study says, particularly when the NHS is so difficult to access.

Yet their concern is that viewers cannot always tell a personal story from a paid promotion.

The team is calling for tighter enforcement of advertising rules and better digital health literacy, so people can spot when a recommendation comes with money attached.

"People deserve to know when someone talking about their weight loss is also receiving a financial incentive," Prescott said.