Patients on high doses of a popular weight-loss drug shed fewer pounds than those on a lower dose, a study has found.
GLP-1 inhibitor drug Mounjaro – also known as tirzepatide and dubbed the ‘King Kong’ of slimming jabs – can help patients shed up to a fifth of their body weight in just a year.
But it appears that less may be more in terms of its effectiveness, with research revealing that patients on a 7.5mg dose actually lost more weight than those on the maximum 15mg dose.
The research, from Oxford Online Pharmacy, tracked the health outcomes of 100 patients prescribed the drug over the
past year. The average weight loss across all participants was 85lb (39kg), but the amount lost varied by dosage.
GLP-1 inhibitor drug Mounjaro – dubbed the ‘King Kong’ of slimming jabs – can help patients shed up to a fifth of their body weight in just a year
All patients were originally placed on a 2.5mg dose of the drug, to help the body adjust to the powerful medication, which was then gradually increased depending on each individual’s response. The most common dose for all patients was 5mg – and 86 per cent of patients maintained a moderate dose of 10mg or lower.
Some, however, were taking as much as 15mg, while others were put on to 12.5mg.
Yet all patients who lost more than a third of their body weight were on the significantly lower 7.5mg dose.
This group of patients also saw the highest average drop in body mass index (BMI).
In fact, two of the participants on the 7.5mg dosage saw their BMI drop up to 13.5 points – the most drastic weight loss outcomes of the whole survey.
The second most effective dosage was the highest, at 15mg.
This phenomenon may be due to the fact that lower doses of the medication hit the ‘sweet spot’ between effectiveness and tolerability, said Kiran Jones, clinical pharmacist at Oxford Online Pharmacy.
‘What this data suggests is that meaningful weight loss isn’t limited to the highest doses,’ he added.
‘For many patients, a mid-range dose such as 7.5mg offers a good balance between effectiveness and tolerability, and that challenges the idea that success means pushing to 15mg.’
Boris Johnson had to stop taking GLP-1 inhibitor jab Ozempic after it triggered severe nausea. Discussing his experience in his column in the Mail, he said he began to dread the weekly injections
Recent research has shown that higher doses of the weight-loss jabs are more likely to cause debilitating gastrointestinal side effects such as vomiting, nausea, bloating, constipation and diarrhoea. Some users have also reported hair loss and vision problems after taking high doses of the drug.
Former Prime Minister Boris Johnson had to stop taking similar GLP-1 inhibitor jab Ozempic – also known as semaglutide – after it triggered severe nausea in June 2023. Discussing his experience in his column in the Mail, he said he began to dread the weekly injections.
As of last month, Mounjaro is available for obese patients in England free of charge from the National Health Service. The drug, which is injected weekly, will be offered to around 220,000 people over the next three years.
More than a million people in the UK are already using it via private clinics, where it costs around £250 per month.
While study participants saw the greatest weight loss on a 7.5mg dose of the jab, not all Mounjaro users will see the same effect, added Mr Jones.
‘While dose does impact weight loss, it’s just one part of a much bigger picture,’ he said. ‘Lifestyle, adherence, and underlying health conditions all play important roles in determining a person’s outcomes.’
