Retatrutide (Triple Agonist)
Also known as: LY3437943, GGG triple agonist, GLP-1/GIP/Glucagon receptor agonist, triple incretin
Summary
Retatrutide is an experimental triple agonist hitting GLP-1, GIP, and glucagon receptors — adding calorie-burning glucagon activity to appetite suppression. Phase 2 results set the record for drug-induced weight loss; Phase 3 trials are still underway, so nothing about approval or long-term safety is settled.
Key Findings at a Glance
- • Retatrutide is the first triple hormone receptor agonist targeting GLP-1, GIP, and glucagon receptors simultaneously, adding a thermogenic component absent from prior incretin therapies.
- • Phase 2 trials showed retatrutide achieves 24.2 percent mean weight loss at 48 weeks, the most profound pharmacological weight loss ever recorded, with weight curves still declining at study end.
- • Despite activating the glucagon receptor, which normally raises blood sugar, retatrutide produces net glucose lowering because GLP-1 and GIP receptor effects overwhelm the glucagon component.
- • Retatrutide reduces liver fat by over 80 percent in NAFLD patients, exceeding the hepatic benefits seen with both semaglutide and tirzepatide and positioning it as a potential NASH breakthrough.
Retatrutide (Triple Agonist) Overview & Molecular Profile
Retatrutide is a first-in-class triple GLP-1/GIP/glucagon receptor agonist in Phase 3 development for obesity and type 2 diabetes. It combines GLP-1 and GIP receptor activation (appetite suppression, insulin secretion) with glucagon receptor agonism (thermogenesis, hepatic fat oxidation), producing up to 24% body weight loss at 48 weeks in Phase 2 trials. Primary research applications include obesity, type 2 diabetes, MASH, and metabolic-cardiovascular disease.
Mechanism of Action: Receptor Agonism & Metabolic Pathways
Retatrutide simultaneously activates three G-protein coupled receptors involved in metabolic regulation. GLP-1 receptor activation enhances glucose-dependent insulin secretion, suppresses glucagon release, delays gastric emptying, and reduces appetite through hypothalamic effects. GIP receptor activation augments insulin secretion and may enhance the metabolic effects of GLP-1. Glucagon receptor activation increases hepatic glucose production acutely but more importantly promotes lipolysis (fat breakdown), thermogenesis (energy expenditure), and amino acid catabolism, potentially offsetting any hyperglycemic tendency. The net effect is profound appetite suppression combined with increased energy expenditure, addressing both sides of the energy balance equation.
Retatrutide Pharmacokinetics: Engineered Once-Weekly Triple Agonism
Retatrutide has the most rigorously characterized pharmacokinetic profile of any multi-receptor incretin agonist in development. Phase 1 studies established dose-proportional exposure and a half-life of approximately six days — long enough for once-weekly subcutaneous dosing — and Phase 2 trials confirmed a clean exposure-response relationship across a twelve-fold dose range.
The 6-Day Half-Life and Once-Weekly Design
Retatrutide is a single engineered peptide whose pharmacokinetics were defined before efficacy trials began.
- • Measured Half-Life: In the Phase 1b multiple-ascending-dose trial in type 2 diabetes, retatrutide's pharmacokinetics were dose proportional with a half-life of approximately 6 days, supporting once-weekly dosing (PMID 36354040).
- • Single-Dose Durability: In the Phase 1 single-ascending-dose study, the pharmacokinetic profile supported once-weekly dosing, and a reduction in body weight persisted up to day 43 after a single dose — pharmacodynamic effects outlasting even the multi-day plasma presence (PMID 35985340).
- • Balanced Receptor Pharmacology: In vitro, retatrutide shows balanced glucagon receptor and GLP-1 receptor activity with relatively greater GIP receptor activity — one molecule producing three simultaneous receptor exposures from a single injection (PMID 35985340).
Dose Proportionality and Exposure-Response
Across Phase 1b and both Phase 2 programs, escalating dose produced escalating, orderly pharmacodynamic effect — the signature of predictable exposure-response.
- • Phase 1b Dose Range: Weekly doses of 0.5, 1.5, 3, 3/6, and 3/6/9/12 mg (stepwise escalation cohorts) produced dose-proportional pharmacokinetics across the full tested range (PMID 36354040).
- • Phase 2 Obesity Exposure-Response: At 48 weeks, mean weight change was −8.7% (1 mg), −17.1% (4 mg), −22.8% (8 mg), and −24.2% (12 mg) versus −2.1% with placebo — a near-monotonic dose-response across a twelve-fold exposure range (PMID 37366315).
- • Phase 2 Diabetes Confirmation: In type 2 diabetes, retatrutide produced dose-dependent reductions in HbA1c (up to −2.02%) and body weight (up to −16.9%) over 36 weeks, confirming the exposure-response pattern in a second population (PMID 37385280).
- • Dose-Dependent Chronotropic Effect: Heart rate increases were dose-dependent, peaked at 24 weeks, and declined thereafter — an exposure-linked physiological effect with a defined time course (PMID 37366315).
Titration as a Pharmacokinetic Strategy
Both Phase 2 programs used gradual dose escalation, exploiting the 6-day half-life to let steady-state exposure build slowly and blunt peak-concentration adverse effects.
- • Stepwise Escalation Design: Phase 1b top doses were attained via stepwise dose escalations rather than direct administration of target doses, and Phase 2 assigned participants to initial doses of 2 mg or 4 mg before escalation to maintenance (PMID 36354040).
- • Tolerability Benefit: Gastrointestinal adverse events in the obesity trial were dose-related but partially mitigated by the lower 2 mg starting dose compared with starting at 4 mg — direct evidence that escalation rate, not just maintenance exposure, drives tolerability (PMID 37366315).
- • Steady-State Logic: With a ~6-day half-life, plasma accumulation reaches steady state over roughly four to five weeks per dose step — the 4-week escalation interval used in Phase 2 aligns each increase with achieved steady-state exposure (PMID 36354040).
Research-Observed Effects
Unprecedented Weight Loss
Moderate ResearchPhase 2 clinical trials demonstrated retatrutide produces the most profound weight loss ever seen with pharmacotherapy, with participants at the highest dose (12mg weekly) achieving mean weight loss of 24.2% at 48 weeks. This approaches and may exceed typical bariatric surgery outcomes for some procedures. Studies show dose-dependent weight reduction with significant effects even at lower doses, and weight loss trajectories that had not yet plateaued at study end, suggesting potential for even greater effects with longer treatment. Research documents preferential loss of fat mass with relative preservation of lean body mass, and preferential reduction of visceral adipose tissue. The triple agonist mechanism addresses weight through both reduced caloric intake and increased energy expenditure.
Enhanced Glycemic Control
Moderate ResearchClinical trials demonstrate dramatic improvements in glycemic parameters in patients with type 2 diabetes, with HbA1c reductions exceeding 2% at higher doses. Research shows retatrutide produces glycemic improvements comparable to or exceeding tirzepatide despite the glucagon receptor activation component, suggesting the glucose-lowering effects of GLP-1 and GIP activation offset glucagon's hyperglycemic potential. Studies document improvements in fasting glucose, postprandial glucose, and glucose variability measures. The glucose-dependent insulin secretion mechanism maintains low hypoglycemia rates despite profound glucose lowering. Research explores potential for diabetes remission in responsive patients.
Enhanced Energy Expenditure
Preliminary ResearchThe glucagon receptor activation component of retatrutide produces thermogenic effects that increase resting energy expenditure, a mechanism not seen with GLP-1 or dual GLP-1/GIP agonists. Research in animal models demonstrates increased brown adipose tissue activity and fat oxidation. Clinical studies suggest the energy expenditure component contributes to weight loss beyond that achieved through appetite suppression alone. This addresses a key limitation of prior anti-obesity medications where adaptive thermogenesis (metabolic slowing) can limit weight loss durability. Studies are investigating the magnitude and sustainability of metabolic rate increases with retatrutide treatment.
Liver Fat Reduction
Moderate ResearchClinical trials document dramatic reductions in liver fat content in patients with NAFLD, with studies showing >80% relative reduction in hepatic fat measured by MRI-PDFF at higher doses. The combination of weight loss, improved insulin sensitivity, and glucagon-mediated effects on hepatic lipid metabolism may produce additive benefits for fatty liver disease. Research shows improvements in liver enzymes and non-invasive fibrosis markers. The magnitude of liver fat reduction exceeds that seen with GLP-1 agonists and even tirzepatide, positioning retatrutide as a potential breakthrough for NASH treatment. Dedicated NASH trials are underway.
Cardiovascular Risk Factor Improvement
Preliminary ResearchClinical trials demonstrate comprehensive improvements in cardiometabolic risk factors including significant blood pressure reductions, improved lipid profiles with decreased triglycerides and increased HDL cholesterol, and reduced inflammatory markers. Research shows reductions in waist circumference and visceral adipose tissue that correlate with metabolic improvements. Studies document improvements in insulin sensitivity and metabolic syndrome components. The glucagon receptor activation may provide unique benefits for cardiac function through direct effects on the heart. Cardiovascular outcomes trials are planned to evaluate effects on hard clinical endpoints.
Safety & Tolerability
Retatrutide is an investigational triple agonist with substantial human Phase 1b/2 safety data. In its Phase 2 trials, the most common adverse events were gastrointestinal — nausea, diarrhea, vomiting, and constipation — described as mild-to-moderate and dose-related, and partially mitigated by a lower starting dose. The adverse-event profile was characterized as consistent with GLP-1 and GIP/GLP-1 receptor agonists. Retatrutide is not approved for any use.
Human data: Human evidence is comparatively extensive for an investigational peptide: completed first-in-human Phase 1b and Phase 2 trials in type 2 diabetes, obesity, and MASLD, with a Phase 3 program (TRIUMPH) ongoing. Long-term safety and cardiovascular outcomes are not yet established — no completed cardiovascular outcomes trial exists as of 2026 — and dose-dependent increases in heart rate were observed in Phase 2, a class effect under continued study.
Regulatory status: Not approved by the FDA or any regulatory agency; investigational, in Phase 3 development.
- PubMed 37366315
In the Phase 2 obesity trial, the most common adverse events were gastrointestinal and dose-related, mostly mild-to-moderate, and were partially mitigated by a lower (2 mg vs 4 mg) starting dose; dose-dependent heart-rate increases were observed, peaking around 24 weeks.
Human trial - PubMed 37385280
In the Phase 2 type 2 diabetes trial, the most common adverse events were gastrointestinal (nausea, diarrhoea, vomiting, constipation), mild-to-moderate and dose-dependent (roughly 13% at the lowest dose to 50% at a higher dose); no severe hypoglycaemia and no deaths were reported.
Human trial - PubMed 36354040
First-in-human Phase 1b multiple-ascending-dose research characterized retatrutide's initial safety and tolerability and informed the gradual dose-escalation schedule used in later trials.
Human trial
Research Protocol Doses Reported in Published Literature
Research Disclaimer: Doses reported below are from published preclinical research protocols. Retatrutide (Triple Agonist) is not approved for human use by the FDA or any regulatory agency. This information is provided for research reference only and does not constitute a dosing recommendation.
| Route | Dose | Frequency | Notes |
|---|---|---|---|
| Subcutaneous (Phase 2 – obesity) | 1 mg → 2 → 4 → 8 → 12 mg | Once weekly | Phase 2 dose escalation; Phase 3 doses under investigation; not yet approved as of 2026 |
All doses above are reported from published research protocols using laboratory subjects. Refer to the cited studies in the Research Studies section above for original source data.
Research Studies & References
Retatrutide, a GIP, GLP-1 and Glucagon Receptor Agonist, for People with Type 2 Diabetes
Rosenstock J, Frias J, Jastreboff AM, et al.
Lancet (2023)
This pivotal phase 2 trial evaluated retatrutide in 281 participants with type 2 diabetes over 36 weeks. The study demonstrated dose-dependent effects on both glycemic control and weight loss, with the 12mg dose achieving HbA1c reductions of 2.02% and weight loss of 16.9%. Importantly, 82% of participants at the 12mg dose achieved HbA1c <7%, and 26% achieved normal HbA1c <5.7%. The study documented significant improvements in liver fat content and cardiometabolic parameters. Gastrointestinal adverse events were common but generally transient and manageable. These results established retatrutide as a viable approach for type 2 diabetes with effects surpassing currently available agents.
Triple-Hormone-Receptor Agonist Retatrutide for Obesity - A Phase 2 Trial
Jastreboff AM, Kaplan LM, Frias JP, et al.
New England Journal of Medicine (2023)
This phase 2 trial evaluated once-weekly subcutaneous retatrutide in 338 adults with obesity over 48 weeks, demonstrating substantial dose-dependent weight loss. Participants receiving the highest dose (12mg weekly) achieved a least-squares mean weight change of -24.2% at 48 weeks. At that dose, 100%, 93%, and 83% of participants achieved weight reductions of at least 5%, 10%, and 15%, respectively, compared with 27%, 9%, and 2% on placebo. The most common adverse events were gastrointestinal, dose-related, and mostly mild to moderate, and were partially mitigated by lower starting doses. The authors concluded that retatrutide treatment for 48 weeks resulted in substantial reductions in body weight in adults with obesity.
Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial
Sanyal AJ, Kaplan LM, Frias JP, et al.
Nature Medicine (2024)
Phase 2a trial (98 participants) in which once-weekly retatrutide produced dose-dependent reductions in liver fat in patients with MASLD, with mean relative reductions at 24 weeks of 81.4% (8mg) and 82.4% (12mg); normal liver fat (<5%) was achieved by 79% and 86% of participants at those doses, respectively.
LY3437943, a novel triple GIP, GLP-1, and glucagon receptor agonist in people with type 2 diabetes: a phase 1b, multicentre, double-blind, placebo-controlled, randomised, multiple-ascending dose trial
Urva S, Coskun T, Loh MT, et al.
The Lancet (2022)
First-in-human multiple-ascending dose study establishing retatrutide's safety, tolerability, and dose-dependent metabolic effects in type 2 diabetes.
Comparative Research
Explore in-depth research analyses and comparative studies featuring Retatrutide (Triple Agonist).
Comparative Clinical Analysis
Retatrutide vs Tirzepatide: Triple Agonist vs Dual Agonist Comparison for Metabolic Research
Retatrutide, a first-in-class triple hormone receptor agonist targeting GLP-1, GIP, and glucagon receptors, demonstrates unprecedented weight loss efficacy in clinical trials—up to 24.2% body weight reduction at 48 weeks. Compared to Tirzepatide's dual GIP/GLP-1 mechanism achieving 20.2% weight loss at 72 weeks, Retatrutide's addition of glucagon receptor agonism appears to enhance energy expenditure and hepatic lipid metabolism. While Tirzepatide has FDA approval and extensive real-world data, Retatrutide remains in Phase 3 trials with potential for superior metabolic outcomes.
Retatrutide vs Semaglutide: Triple Agonist vs GLP-1 Agonist for Next-Generation Obesity Research
Retatrutide's triple receptor mechanism (GLP-1/GIP/Glucagon) achieves significantly greater weight loss than Semaglutide's single GLP-1 pathway—24.2% vs 14.9% body weight reduction in clinical trials. While Semaglutide (Ozempic/Wegovy) represents the current gold standard with FDA approval and extensive real-world data, Retatrutide's Phase 2 results suggest it may nearly double the efficacy. The addition of GIP and glucagon agonism provides synergistic effects on insulin secretion, energy expenditure, and hepatic lipid metabolism not achievable with GLP-1 alone.
Retatrutide vs CagriSema: Triple Agonist vs Amylin-GLP-1 Combination in Next-Generation Obesity Pharmacology
Retatrutide and CagriSema are the two leading candidates to succeed GLP-1 monotherapy in obesity pharmacology, built on opposing design philosophies. Retatrutide is a single engineered peptide activating GIP, GLP-1, and glucagon receptors — the glucagon component adding energy expenditure and hepatic fat effects — and produced 24.2% mean weight loss at 48 weeks in a 338-participant Phase 2 trial, the largest reduction reported for an obesity drug candidate at that duration. CagriSema is a fixed-dose combination of two validated peptides, the amylin analog cagrilintide plus semaglutide, which produced 20.4% weight loss at 68 weeks in the 3,417-participant Phase 3 REDEFINE 1 trial. Retatrutide holds the efficacy-ceiling claim but is still completing Phase 3 (the TRIUMPH program); CagriSema holds the more mature regulatory position with two completed and published Phase 3a trials. No head-to-head trial exists, and the different trial phases, durations, and populations make cross-trial ranking provisional.
Frequently Asked Questions
How does retatrutide differ from tirzepatide?
Retatrutide (triple agonist: GLP-1 + GIP + glucagon) adds glucagon receptor agonism to tirzepatide's dual agonism (GLP-1 + GIP). The glucagon receptor component adds thermogenesis—glucagon directly activates brown adipose tissue to increase energy expenditure—that is absent from tirzepatide. Phase 2 data: retatrutide achieved 24.2% weight loss at 48 weeks vs tirzepatide's 22.5% at 72 weeks in different trials (not a direct comparison). Retatrutide's 48-week weight loss curves were still declining, suggesting the 24.2% figure underestimates its maximum effect. Retatrutide is in Phase 3 trials and has not yet been approved.
Does the glucagon receptor activation cause hyperglycemia?
This is the central pharmacological paradox of triple agonists. Glucagon normally signals hepatic glucose production and raises blood sugar. However, in clinical trials retatrutide produces robust glucose lowering despite glucagon receptor activation. The GLP-1 receptor activation suppresses glucagon secretion and directly enhances glucose-dependent insulin release; GIP receptor activation also enhances insulin secretion. These combined insulinotropic effects dramatically outweigh the hepatic glucagon effect at the doses used. The clinical result is net HbA1c reduction of ~2% in T2D patients—despite the glucagon agonism.
What is retatrutide's current development status as of 2026?
Retatrutide completed Phase 2 trials in 2023 demonstrating record weight loss (24.2% at 48 weeks in obesity; 16.9% weight loss + 2.02% HbA1c reduction in T2D). Phase 3 trials are underway (TRIUMPH program) evaluating retatrutide for obesity and T2D. FDA approval is not expected before 2026–2027. The primary competitive concern is whether its modest incremental weight loss advantage over tirzepatide (the current standard) justifies its differentiated side effect profile, particularly if glucagon agonism increases bone turnover, hepatic glucose production at higher doses, or cardiovascular risk.
Why is retatrutide particularly interesting for fatty liver disease?
Retatrutide reduces liver fat by over 80% in NAFLD patients—exceeding the hepatic fat reduction seen with semaglutide (~50–60%) or tirzepatide (~65–75%) in comparable Phase 2 populations. The glucagon receptor component is key: glucagon directly stimulates hepatic fatty acid oxidation and promotes fat mobilization from the liver. GLP-1 reduces fat uptake and de novo lipogenesis. The combined mechanisms create a particularly potent anti-steatotic effect. MASH (metabolic dysfunction-associated steatohepatitis) is an enormous unmet need, and retatrutide's hepatic efficacy makes it a leading candidate for potential MASH approval alongside or following obesity approval.
What is retatrutide's dosing protocol in Phase 3 trials?
Based on Phase 2 data, retatrutide Phase 3 trials use a multi-step titration: starting at 2 mg SC weekly for 4 weeks, then escalating to 4 mg, 8 mg, and 12 mg at 4-week intervals. This slower titration vs. tirzepatide is partly driven by the glucagon receptor component, which may cause greater GI effects at higher doses. The highest dose studied in Phase 2 was 12 mg weekly, which produced the maximum weight loss outcomes. Whether a 12 mg maintenance dose will be the approved dose, or whether a higher ceiling will be tested in Phase 3, depends on tolerability data at the 12 mg level across larger populations.
How might retatrutide's glucagon agonism affect bone density?
Glucagon receptors are expressed on osteoblasts and osteoclasts. Glucagon signaling stimulates bone formation markers (osteocalcin, bone-specific alkaline phosphatase) in some models. However, the weight loss itself—particularly loss of mechanical loading on the skeleton from reduced adipose tissue mass—can reduce bone mineral density. Long-term data on bone outcomes in triple agonist trials is limited. Phase 3 programs for retatrutide will need to characterize any net bone effects, particularly in postmenopausal women who are already at elevated fracture risk. This remains an open safety question awaiting longer-term data.
What differentiates retatrutide from other triple agonist peptides in development?
Several triple agonist programs exist in parallel with retatrutide (Eli Lilly): pemvidutide (Altimmune) as a GLP-1/glucagon dual agonist with liver emphasis; efinopegdutide (MSD) as GLP-1/glucagon dual; CT-388 (Structure Therapeutics) as an oral GLP-1/GIP; HM15275 (Hanmi Pharmaceutical) as GLP-1/GIP/glucagon. Retatrutide is distinguished by Eli Lilly's manufacturing scale, clinical trial infrastructure, Phase 2 efficacy data quality, and integration into the company's GLP-1 agonist ecosystem (Mounjaro, Zepbound). Its head-to-head competition will ultimately be with tirzepatide—the question being whether the incremental efficacy justifies additional development risk and a higher side effect burden.
What cardiovascular outcomes trial data exists for retatrutide?
As of 2026, no completed cardiovascular outcomes trial (CVOT) data exists for retatrutide—Phase 2 data provides cardiometabolic markers (blood pressure, lipids, weight) but not hard CV event outcomes. A CVOT is expected as part of the Phase 3 program given FDA requirements for obesity drugs to demonstrate CV safety. The glucagon receptor component introduces some theoretical uncertainty: glucagon increases heart rate and hepatic glucose output, which historically raised CV safety questions. However, Phase 2 data showed no adverse cardiac signals and the GLP-1 component's established cardioprotective properties (reduced MACE, per semaglutide and liraglutide data) are expected to offset glucagon-related concerns.
Related Peptides
View allTirzepatide (GLP-1/GIP)
Tirzepatide is a first-in-class dual GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 receptor agonist, providing synergistic metabolic effects for diabetes and obesity research.
Semaglutide (GLP-1)
Semaglutide is a long-acting GLP-1 (glucagon-like peptide-1) receptor agonist that mimics the incretin hormone GLP-1, regulating blood glucose levels, appetite, and body weight through multiple metabolic pathways.
Liraglutide (GLP-1)
Liraglutide is a GLP-1 receptor agonist with 97% amino acid sequence homology to native GLP-1, modified with a palmitic acid chain for extended duration of action, used in research for diabetes and obesity.
Survodutide
Survodutide is a dual glucagon and GLP-1 receptor agonist developed by Boehringer Ingelheim and Zealand Pharma, investigated for obesity, type 2 diabetes, and metabolic dysfunction-associated steatohepatitis (MASH).
Mazdutide
Mazdutide is a dual GLP-1 and glucagon receptor agonist based on an oxyntomodulin analog, developed by Innovent Biologics in partnership with Eli Lilly, and the first drug of its class to receive regulatory acceptance for obesity in China.
Related Comparisons
Retatrutide vs Tirzepatide
Retatrutide, a first-in-class triple hormone receptor agonist targeting GLP-1, GIP, and glucagon receptors, demonstrates unprecedented weight loss efficacy in clinical trials—up to 24.2% body weight reduction at 48 weeks. Compared to Tirzepatide's dual GIP/GLP-1 mechanism achieving 20.2% weight loss at 72 weeks, Retatrutide's addition of glucagon receptor agonism appears to enhance energy expenditure and hepatic lipid metabolism. While Tirzepatide has FDA approval and extensive real-world data, Retatrutide remains in Phase 3 trials with potential for superior metabolic outcomes.
Retatrutide vs Semaglutide
Retatrutide's triple receptor mechanism (GLP-1/GIP/Glucagon) achieves significantly greater weight loss than Semaglutide's single GLP-1 pathway—24.2% vs 14.9% body weight reduction in clinical trials. While Semaglutide (Ozempic/Wegovy) represents the current gold standard with FDA approval and extensive real-world data, Retatrutide's Phase 2 results suggest it may nearly double the efficacy. The addition of GIP and glucagon agonism provides synergistic effects on insulin secretion, energy expenditure, and hepatic lipid metabolism not achievable with GLP-1 alone.
Retatrutide vs CagriSema
Retatrutide and CagriSema are the two leading candidates to succeed GLP-1 monotherapy in obesity pharmacology, built on opposing design philosophies. Retatrutide is a single engineered peptide activating GIP, GLP-1, and glucagon receptors — the glucagon component adding energy expenditure and hepatic fat effects — and produced 24.2% mean weight loss at 48 weeks in a 338-participant Phase 2 trial, the largest reduction reported for an obesity drug candidate at that duration. CagriSema is a fixed-dose combination of two validated peptides, the amylin analog cagrilintide plus semaglutide, which produced 20.4% weight loss at 68 weeks in the 3,417-participant Phase 3 REDEFINE 1 trial. Retatrutide holds the efficacy-ceiling claim but is still completing Phase 3 (the TRIUMPH program); CagriSema holds the more mature regulatory position with two completed and published Phase 3a trials. No head-to-head trial exists, and the different trial phases, durations, and populations make cross-trial ranking provisional.