Warning! Weight loss jabs like Ozempic linked to deadly cancer diagnosis in the year after using them
Game-changing weight loss jabs relied on by millions of slimmers and diabetics could raise the risk of thyroid cancer in their first year of use, concerning new research has suggested.
The drugs, which include Mounjaro, Ozempic and Wegovy, have ushered in a new era in the battle against obesity, helping dieters shed up to a fifth of their bodyweight.
But, American doctors — who tracked over 350,000 patients — have now discovered the injections put users at ‘significantly higher’ risk of the disease compared to three other common diabetes drugs.
The overall risk of developing thyroid cancer over the course of six years on the jabs, however, remained ‘low’, experts said.
Scientists, who labelled the findings important, cautioned further research was necessary to confirm their findings.
Around half a million Britons are now thought to be using the medication, which can help them lose up to 20 per cent of their bodyweight in just a few months.
It comes as a Mail on Sunday investigation last week revealed almost 400 Brits had been hospitalised — some with life-threatening complications — since the rollout of jabs such as Wegovy, Mounjaro, and Saxenda.
In 2023, research on mice and rats suggested semaglutide — the powerful ingredient behind Wegovy and Ozempic — could raise the risk of one type of thyroid cancer — medullary thyroid cancer (MTC).
The drugs, which include Mounjaro, Ozempic and Wegovy, have ushered in a new era in the battle against obesity, helping dieters shed up to a fifth of their bodyweight
Last year, the European Medicines Agency also said that research on rodents suggested the artificial hormones packaged in tirzepatide — sold under the brand name Mounjaro — could also increase the risk of MTC.
However, monitoring studies on patients taking the drug to explore this potential risk in humans is still ongoing, given the risk is currently ‘inconclusive’.
In the latest study, researchers from the University of Maryland in Baltimore assessed 351,913 patients with type 2 diabetes who had no history of thyroid cancer and were aged 65 on average.
Over 40,000 were put on the jabs — collectively known as glucagon-like peptide-1 receptor agonists, or GLP-1s agonists.
Others were given three common type 2 diabetes medications, DDP-4 inhibitors, sodium-glucose co-transporter 2 (SGLT2) inhibitors and sulfonylurea therapy.
Over a follow-up of six years, the researchers found the risk for thyroid cancer was ‘significantly higher’ within the first year after GLP-1 initiation, compared to the other 3 drugs.
Writing in the journal JAMA Ophthalmology, however, they added that the relationship was no longer significant when researchers assessed the risk of thyroid cancer across the six year study period.
‘This finding may have been due to enhanced early detection, therefore, further research is necessary to understand the underlying causes of this association,’ the authors wrote.
The scientists also acknowledged the study had some limitations including being unable to differentiate between MTC and other types of thyroid cancer.
Future research assessing this is ‘critical’ to understanding the reason why the jabs have been associated with MTC specifically, they added.
‘These findings highlight the need for further research to fully understand the nature of this association,’ they said.
Until October last year, the number of hospitalisations over the six years since the weight loss jabs first began to be prescribed stood at 279.
But new data obtained from the drugs regulator the the Medicines and Healthcare products Regulatory Agency (MHRA), found cases soared over the four weeks to the end of November, with an extra 118 hospitalisations recorded.
Most of the reactions are gastrointestinal issues such as persistent nausea and diarrhoea, which leave some patients with ‘severe dehydration’.
But some doctors warned they were seeing patients with ‘serious, life-threatening complications’ including seizures, bowel obstruction and inflammation of the pancreas, known as pancreatitis.
Wegovy and Ozempic work by triggering the body to produce a hormone called GLP-1 that is released naturally from the intestines after meals
Like any medication, the jabs are known to cause side effects that vary in both frequency and severity.
Other reported problems include constipation, fatigue, stomach pain, headaches and dizziness.
Bizarre symptoms, such as hair loss, have also been reported among some patients.
Doctors have also long told how they are treating increasing numbers of slim women who end up in hospital after falsely telling online chemists they are overweight to pass eligibility checks.
Under NHS guidelines, only patients who have a body mass index (BMI) of over 35, or a BMI of 30 and at least one weight related health problem like high blood pressure, should be prescribed Wegovy.
UK law forbids the sale of such drugs without a prescription from a medical professional.
Earlier this month, the MHRA also revealed it took down 150 social media posts ‘actively’ selling counterfeit weight loss drugs in 2024.
It came just weeks after the Advertising Standards Authority (ASA) issued a warning to advertisers, businesses and influencers to remove online and social media ads for weight-loss prescription-only medicines targeted at members of the public.
This followed a MailOnline investigation that found social media influencers were being encouraged to illegally promote prescription weight loss jabs to their thousands of followers.
