A battle between tirzepatide and semaglutide has revealed that Mounjaro is “superior” to Wegovy for the “treatment of obesity”.
A trial compared data from two cohorts – patients “with obesity but without type 2 diabetes” using either the maximum tolerated dose of tirzepatide (10 mg or 15 mg) or semaglutide (1.7 mg or 2.4 mg).
It found that both drugs, each glucagon-like peptide-1 receptor agonists (GLP-1RAs), led to significant weight loss.
But tirzepatide (Mounjaro) caused a weight reduction of 20.2% after 72 weeks of treatment, compared with a 13.7% reduction from semaglutide (Wegovy).
Read more: ‘Superior weight loss’ drug: Mounjaro squashing rival Wegovy
To participate in the trial, patients were required to have a body-mass index (BMI) “of 30 or higher or a BMI of 27 or higher and at least one prespecified obesity-related complication”, such as hypertension or cardiovascular disease.
Participants also had to have had “at least one unsuccessful dietary effort for weight reduction” to participate.
The trial studied 750 patients and was conducted between April 2023 and November 2024.
“New generation” of medication
The trial was funded by Eli Lilly – the manufacturer of Mounjaro – and was carried out to compare “the efficacy and safety of tirzepatide as compared with semaglutide in adults with obesity but without type 2 diabetes”, which was previously “unknown”.
Both are “part of a new generation of highly effective medications for the management of obesity”, it said.
For tirzepatide, patients were started on a dose of “2.5 mg once weekly” and this was increased “by 2.5 mg every four weeks until a maximum tolerated dose of 10 mg or 15 mg was reached”.
Read more: Inside the online pharmacy growing weight loss scripts by the thousands
And for semaglutide, participants began with a dose of “0.25 mg once weekly” which was then increased “every four weeks in accordance with recommended dosing (from 0.25 mg to 0.5 mg, 1.0 mg, 1.7 mg, and 2.4 mg) until the 2.4-mg dose was reached”.
Researchers found that “tirzepatide was superior to semaglutide with respect to weight reduction” after 72 weeks of treatment.
The “mean change in body weight” for tirzepatide at the end of the trial was a loss of 22.8 kg, compared with a loss of 15 kg from semaglutide, it said.
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The trial also found that “more participants treated with tirzepatide than those treated with semaglutide had reductions in body weight of at least 10%, 15%, 20%, and 25%”.
And in both trial-treatment groups, “the weight reduction was approximately 6% greater among women than among men”.
It comes after Pharmadoctor data revealed that the popularity of Mounjaro had far surpassed Wegovy in the six months to December.
Read more: Revealed: Pharmacy weight loss consultations rocket twenty-fold
Almost 80% of products dispensed via the Pharmadoctor weight management service were Mounjaro, chief executive Graham Thoms told C+D at the time.
Meanwhile, the platform exclusively told C+D in March that the number of consultations delivered under this service in the previous 12 months – March 2024 to February 2025 – was “twenty times more than the preceding 12-month period”.
And last week, it was revealed that Oushk Pharmacy’s funds have boomed almost 600% - mainly thanks to the thousands of weight loss scripts it processes every month.
