Head-to-Head Comparison: Retatrutide and Tirzepatide Lead Among 7 GLP-1 Weight Loss Drugs
A network meta-analysis of 27 trials and 15,584 patients ranked retatrutide 12mg (−22.1% body weight) and tirzepatide 15mg (−16.5%) as the most effective weight loss treatments among 7 GLP-1 agonists and polyagonists, with dual/triple receptor agonists outperforming single-receptor drugs.
Quick Facts
What This Study Found
Retatrutide 12mg (−22.1% body weight, −17cm waist) and tirzepatide 15mg (−16.5%) were the most effective weight loss treatments. Dual/triple receptor agonists significantly outperformed single GLP-1 receptor agonists across 27 RCTs with 15,584 patients.
Key Numbers
Drugs compared: mazdutide (6/4.5mg), retatrutide (12/8mg), tirzepatide (15/10mg), liraglutide 3.0mg, semaglutide (2.4/1.0mg). RCTs with ≥16-week duration.
How They Did This
Network meta-analysis of 27 RCTs (≥16 weeks duration) from Cochrane Library, PubMed, and Embase through August 2024. Compared mazdutide, retatrutide, tirzepatide, liraglutide, semaglutide, orforglipron, and beinaglutide. Frequentist random-effects model using Stata 16.1.
Why This Research Matters
With multiple GLP-1 weight loss drugs now available or in development, clinicians and patients need evidence-based comparisons. This analysis shows multi-receptor agonists represent the next frontier, with retatrutide potentially doubling the weight loss of earlier drugs like liraglutide.
The Bigger Picture
The GLP-1 drug landscape is evolving rapidly from single-receptor agonists (liraglutide, semaglutide) to dual (tirzepatide) and triple (retatrutide) receptor agonists. This meta-analysis confirms the trend: each additional receptor target adds meaningfully to weight loss. Retatrutide's 22% average weight loss approaches what was previously only achievable with bariatric surgery.
What This Study Doesn't Tell Us
Some drugs (retatrutide, mazdutide) have fewer trials and shorter follow-up than established drugs like semaglutide. Long-term safety data beyond trial periods is unavailable for newer agents. The network meta-analysis relies on indirect comparisons for some drug pairs. Weight regain after discontinuation wasn't assessed.
Questions This Raises
- ?Will retatrutide maintain its weight loss superiority in larger phase 3 trials and real-world use?
- ?What is the long-term safety profile of triple receptor agonists compared to GLP-1-only drugs?
- ?Do patients who lose 20%+ body weight on these drugs maintain the loss, or does weight regain occur after stopping?
Trust & Context
- Key Stat:
- −22.1% body weight Retatrutide 12mg achieved the greatest weight loss among 7 GLP-1 agonists and polyagonists — approaching bariatric surgery results
- Evidence Grade:
- Strong evidence from a network meta-analysis of 27 randomized controlled trials with 15,584 patients. However, newer drugs have fewer supporting trials than established agents.
- Study Age:
- Published in 2024 with literature search through August 2024; includes the most current trial data for all 7 drugs.
- Original Title:
- Seven glucagon-like peptide-1 receptor agonists and polyagonists for weight loss in patients with obesity or overweight: an updated systematic review and network meta-analysis of randomized controlled trials.
- Published In:
- Metabolism: clinical and experimental, 161, 156038 (2024)
- Authors:
- Xie, Zeyu(2), Zheng, Guimei(2), Liang, Zhuoru(2), Li, Mengting, Deng, Weishang, Cao, Weiling
- Database ID:
- RPEP-09562
Evidence Hierarchy
Combines results from multiple studies to find an overall pattern.
What do these levels mean? →Frequently Asked Questions
Which GLP-1 drug causes the most weight loss?
Based on this analysis, retatrutide 12mg leads with an average 22.1% body weight loss, followed by retatrutide 8mg (20.7%) and tirzepatide 15mg (16.5%). Semaglutide 2.4mg (Wegovy) and liraglutide 3.0mg (Saxenda) are less effective but more established.
Are these newer drugs safe?
None of the 7 drugs increased serious adverse events or severe hypoglycemia compared to placebo. Gastrointestinal side effects (nausea, vomiting) are common across all of them. However, the newer multi-receptor agonists have less long-term safety data than established drugs like liraglutide and semaglutide.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-09562APA
Xie, Zeyu; Zheng, Guimei; Liang, Zhuoru; Li, Mengting; Deng, Weishang; Cao, Weiling. (2024). Seven glucagon-like peptide-1 receptor agonists and polyagonists for weight loss in patients with obesity or overweight: an updated systematic review and network meta-analysis of randomized controlled trials.. Metabolism: clinical and experimental, 161, 156038. https://doi.org/10.1016/j.metabol.2024.156038
MLA
Xie, Zeyu, et al. "Seven glucagon-like peptide-1 receptor agonists and polyagonists for weight loss in patients with obesity or overweight: an updated systematic review and network meta-analysis of randomized controlled trials.." Metabolism: clinical and experimental, 2024. https://doi.org/10.1016/j.metabol.2024.156038
RethinkPeptides
RethinkPeptides Research Database. "Seven glucagon-like peptide-1 receptor agonists and polyagon..." RPEP-09562. Retrieved from https://rethinkpeptides.com/research/xie-2024-seven-glucagonlike-peptide1-receptor
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.