Increasing the dosage of popular weight loss injections such as Mounjaro and Wegovy to their maximum levels may not lead to substantially greater weight loss, according to findings from two studies. The research suggests that patients can achieve similar weight loss outcomes on lower or medium-strength doses as they do on the highest available doses.
One study, conducted by digital healthcare company HeliosX and analyzing data from over 630,000 UK users of tirzepatide (Mounjaro), found that after six months, patients taking a 10mg dose lost an average of 14.4% of their starting weight. Those on 12.5mg lost 14.9%, and patients on the maximum 15mg dose lost 15.1%. The difference in weight loss between the 10mg and 15mg doses was approximately 0.7%, equivalent to about one pound.
The cost savings could be significant, as the 15mg dose of Mounjaro can cost up to £340 per month, while lower doses like 10mg and 12.5mg range from £260 to £280. Researchers noted that many patients achieved substantial weight loss without needing the maximum dose, a finding particularly relevant in the UK where most individuals pay for these medications privately.
This study also highlighted the importance of consistent medication use. Patients who remained on the treatment continuously lost about a fifth of their body weight after 12 months, compared to those who paused their treatment, who lost approximately 13.5%.
A separate analysis by weight-loss provider Oviva involving 148 patients using semaglutide (Wegovy) indicated similar trends. In this study, half of the patients gradually reduced their dose, typically settling around 1.7mg, while the other half remained on the 2.4mg strength. After 18 months, both groups showed comparable weight loss, ranging from 18% to 20% of their body weight. Those who lowered their dosage also reported no increased issues with hunger.
Medication costs differ for these lower doses, with the 2.4mg dose of Wegovy priced around £230 and the 1.7mg dose at approximately £180. These findings suggest that patients might save up to £80 per month, or around £960 annually, by opting for lower, potentially equally effective, doses.
Furthermore, sticking to lower doses might reduce the risk of severe side effects. The Medicines and Healthcare products Regulatory Agency (MHRA) warns that side effects, most commonly gastrointestinal issues like nausea, vomiting, and diarrhea, can be most pronounced at the start of treatment or when increasing the dose.
The MHRA advises that any changes to medication dosage or type should only be made in consultation with a healthcare professional. They emphasize that GLP-1 medications vary in strength, usage, and the conditions they treat, and switching without medical advice could increase the risk of adverse effects or reduce treatment efficacy.