Weight-loss injections such as Mounjaro and Ozempic may be associated with an almost 50 per cent higher risk of impaired taste and smell, according to a study.
The drugs are already known to curb appetite — with many users shedding about 15 per cent of their body weight — but researchers have now found they may also alter how food tastes and smells.
Mounjaro is currently available privately to people with a BMI of 27 or above if they also have a weight-related health problem, such as heart disease, high blood pressure or sleep apnoea.
For patients with type 2 diabetes, tirzepatide — marketed as Mounjaro — is approved for NHS use and is usually prescribed when standard treatments have failed to work well enough.
Ozempic can also be considered for people whose condition has not been adequately controlled after trying three other medicines.
Around 1.6 million people in the UK are thought to be using these injections, collectively known as GLP-1 drugs, while thousands more are waiting for a new tablet version of Wegovy.
Researchers identified the possible connection while examining how the injections affect patients’ relationship with food.
They found that changes to smell and taste occur in roughly two out of every 1,000 people with type 2 diabetes, but the use of weight-loss jabs can raise that likelihood to nearly double.
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.
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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.
The theory is these drugs may be able to alter how appetising flavours and smells are perceived, making sugary, processed foods that contribute to weight gain less appealing.
The team concluded that their findings may have several clinical implications and that older patients and those with predisposing conditions may benefit from closer monitoring – as sensory changes can pre-empt neurological conditions.
Mounjaro is prescribed for the management of diabetes in specific circumstances
However, they added discontinuation should not be routine, given the established health benefits of the drug, such as better blood sugar control and reduced heart attack risk.
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.
