Weight loss jabs like Mounjaro and Ozempic have been linked with a nearly 50 per cent increased risk of damaged taste and smell, a study has found.
While the impact of the drugs on people’s appetite has been well-established – with users losing around 15 per cent of their body weight – research has found the jabs can also change the taste and smell of food.
Mounjaro is available privately to patients with a BMI of 27 with a weight-related condition, like heart disease, high blood pressure or sleep apnoea.
For those with type 2 diabetes, tirzepatide – sold under the brand name Mounjaro – is licensed for use on the NHS and is typically prescribed if existing treatments prove ineffective.
Ozempic may be recommended when three other medications have not been effective in managing the condition.
Currently, an estimated 1.6 million people in the UK are estimated to be on the jabs, collectively known as GLP-1s, with thousands waiting for a new pill form of Wegovy.
Experts made the link when they looked at the impact of the jabs on patients’ relationship with food.
They discovered that while around two in every one thousand people with type 2 diabetes will experience changes in their smell and taste, weight loss jabs can almost double the likelihood.
Weight loss jabs alter people’s perception of taste and smell, research suggest
The study – published in JAMA Otolaryngology – included data from more than 870,000 patients and 170 healthcare institutions worldwide from 2017-26.
All participants had a type 2 diabetes diagnosis. Half were prescribed GLP-1s while the control group managed their condition with other diabetes medication.
Results showed that patients on the jabs were about 50 per cent more likely to report food tasting and smelling different than before.
However, the researchers stressed the side effect is rare.
People with type 2 diabetes are already more likely to experience problems with smell and taste, as a result of nerve damage and poor blood flow the researchers explained but weight loss jabs may exacerbate the effect.
These drugs not only act in the gut and brain areas that control appetite, but also on taste bud cells and areas in the brain that process taste, smell and reward.
‘Taste doesn’t only happen on the tongue,’ Dr Madusha Peiris, an expert in appetite regulation who wasn’t involved in the study explains.
‘When we eat, we consciously register sweet, bitter, umami and sour but the same nutrients are being ‘tasted’ a second time, lower down, in the gut.
‘The gut is lined with sensor cells that sample what we eat and in response release hormones like GLP-1 that tell the brain we’re full. So the body is reading food in two places, and taste and fullness are wired into the same nutrient-sensing system.
That shared wiring is why these drugs can reach the senses. With GLP-1 at levels far above normal, you’re pushing a signal the system was built to fire briefly, in the very pathway that links nutrient detection to flavour. It’s not surprising that perception of taste and smell can shift as a result.
‘What this study shows is exactly that association with increased frequency of reported taste and smell disturbances in people taking these medications. But why it happens, the actual cause, is still unknown.’
Mounjaro is prescribed for the management of diabetes in specific circumstances
A 2025 study similarly found that around one in five patients taking Ozempic, Wegovy or Mounjaro report foods tasting saltier or sweeter than before, but the perception of bitterness or sourness was unchanged.
Users who reported a change in taste were also twice as likely to say they felt fuller – and this was especially true of people who found food sweeter than before.
Of these, 67 per cent reported a reduction in appetite and were 85 per cent more likely to experience a reduction in cravings compared to those whose taste buds didn’t change.
However, experts are not convinced that changes in taste alone are enough to drive body weight reduction.
Rather, weight loss depends on a number of factors, such as physical exercise, diet, sleep, stress and long-term eating patterns.
It comes just weeks after a new pill form of Wegovy was approved for use in the UK.
The daily pill contains semaglutide, the same appetite-suppressing ingredient used in a number of the jabs – part of a new wave of treatments alongside Mounjaro that have transformed weight loss.
Take-up of the pill is expected to be monumental, with recent figures suggested that twice as many people would be willing to take a tablet than an injection.
