Review ranks average weight loss across tirzepatide, semaglutide, and liraglutide trials

What happened

A systematic review and network meta-analysis examined three medicines used for obesity: tirzepatide, semaglutide, and liraglutide. Eligible participants were adults who did not have type 2 diabetes. Four research databases were searched through May 2025 for phase 3 randomized trials that included at least one of those treatments.

The analysis included 15 trials and 14,059 participants after screening 1,420 records. Researchers used a frequentist random-effects network model. This method combines direct comparisons within trials with indirect comparisons connected through a shared control, often placebo. It can estimate how regimens compare even when they have not all been tested head to head.

Every included treatment and dose reduced body weight more than placebo by a statistically significant amount. Maximum-tolerated tirzepatide led the reported hierarchy. Fixed tirzepatide doses of 15 mg and 10 mg followed, then semaglutide 2.4 mg. At the bottom, liraglutide 3 mg followed the 5 mg tirzepatide regimen.

Readers cannot recover a pooled weight change in percent or kilograms for every regimen from the indexed abstract. The abstract also omits uncertainty around each rank and does not say how often two active regimens were compared directly in a randomized trial.

In the safety analysis, the chance of reporting at least one adverse event was higher with tirzepatide or semaglutide than with placebo. That association was not reported for liraglutide. The abstract's broad any-event measure does not tell readers how many events were gastrointestinal, severe, treatment-ending, or judged related to a medicine.

What it means

The review offers a structured comparison across major phase 3 programs. Its overall finding is consistent with larger average weight reductions at higher tirzepatide regimens among the studied adults without diabetes.

Network analysis can be more informative than placing headline percentages from separate trials side by side. It still depends on the trials being sufficiently comparable in participant characteristics, lifestyle support, follow-up, dose escalation, outcome definitions, and handling of missing data.

What it does not mean

The ranking is not a treatment ladder for every patient. Most active-treatment comparisons were not direct head-to-head trials, and randomization within one trial does not remove all differences between separate trial programs. A top-ranked group average does not guarantee greater loss or better tolerability for an individual.

The review was limited to selected phase 3 regimens in adults without type 2 diabetes. Its results should not be extended to children, people with diabetes, different doses, compounded products, or patients excluded from the source trials.

The safety result does not establish that liraglutide is safer than the other medicines. Failure to find a higher risk for a broad endpoint can reflect event definitions, sample size, uncertainty, or differences across trials. Treatment decisions also involve contraindications, route, cost, access, prior response, and patient preference, none of which can be resolved by a weight-loss ranking alone.