Weekly semaglutide beats daily liraglutide for weight loss

GLP-1 receptor agonists have transformed the treatment of excess weight, and their ability to drive weight loss in people with diabetes is widely recognised. But the class contains meaningfully different drugs: semaglutide is injected once a week, while liraglutide is injected once a day. Convenience aside, patients and clinicians want to know which produces better results, and until now limited data existed comparing the two directly. This analysis pooled the head-to-head randomised trials to answer that question.

The authors systematically searched the Cochrane Library, PubMed and ScienceDirect from inception until July 2024 for randomised controlled trials directly comparing once-weekly semaglutide against once-daily liraglutide. Three trials qualified, contributing 922 patients in total. Results were pooled using a random effects model, examining body weight, HbA1c and fasting plasma glucose, along with the risk of severe adverse effects and gastrointestinal adverse effects.

Once-weekly semaglutide came out ahead on every efficacy measure: it reduced body weight by a weighted mean difference of 4.55 beyond liraglutide, lowered HbA1c by 0.46 more, and cut fasting plasma glucose by 1.23 more. On safety, the two drugs looked similar. The risk of severe adverse effects and of gastrointestinal adverse effects did not differ significantly between groups, so the efficacy gap did not come with a detectable safety cost in these trials.

These results align with semaglutide's reputation as the more potent of the two agents, and they add a formal pooled estimate to what had been scattered head-to-head data. Three trials is a slender base, though, and the pooled totals cannot say how the comparison plays out across different doses, durations or patient groups. The uncertainty around the safety comparisons also means rarer harms cannot be ruled in or out. Larger and longer comparisons would firm up both the size of the advantage and its limits.

If GLP-1 medication is a conversation you are having, or expect to have, with a doctor, this is useful context: the weekly drug outperformed the daily one on weight, long-term blood sugar and fasting glucose in direct comparisons, with comparable side effect rates. The choice between these medicines involves far more than a pooled average, including availability, cost and individual response. Worth knowing, then, rather than a decision made for you.