Retatrutide Evidence Profile
Last Updated: May 2026An interactive research-focused summary of retatrutide, the investigational GIP, GLP-1, and glucagon receptor agonist, with clear visualizations of key clinical endpoints.
Efficacy snapshot
A broader metabolic signal
Retatrutide has been studied as a single molecule that activates GIP, GLP-1, and glucagon receptors. Published Phase 2 research reported dose-responsive changes across body weight, glycemic control, and hepatic fat endpoints.
Triple-receptor activity designed for multi-pathway metabolic research.
The clinical program has drawn attention because the investigational molecule combines appetite-related incretin biology with glucagon receptor activity, a pathway associated with energy expenditure and hepatic lipid metabolism.
Dose-responsive weight outcomes
Higher retatrutide doses were associated with larger mean reductions in body weight through 48 weeks, with the curve continuing downward at the final observation point.
Hepatic fat endpoint strength
The NAFLD sub-study reported substantial relative liver fat reductions, with a high proportion of participants reaching the <5% liver fat normalization threshold.
Glycemic control research
In type 2 diabetes research, retatrutide was evaluated against placebo and dulaglutide, with dose-related HbA1c reductions reported by week 36.
Pharmacology
Mechanism of action
Retatrutide is a single peptide engineered to activate three distinct metabolic pathways. This triple-agonist approach aims to maximize energy expenditure and regulate appetite concurrently.
Glucagon Receptor
Unlike earlier incretins, retatrutide includes glucagon agonism. In pharmacological models, this pathway drives hepatic fat clearance (lipolysis) and increases resting energy expenditure and thermogenesis, countering the metabolic slowdown typically seen in caloric deficit.
GLP-1 Receptor
Glucagon-like peptide-1 (GLP-1) signaling remains a core pillar, acting on central nervous system pathways to induce early satiety and reduce hunger signals. It also contributes to glucose-dependent insulin secretion and delayed gastric emptying.
GIP Receptor
Glucose-dependent insulinotropic polypeptide (GIP) agonism works synergistically with GLP-1 to enhance glycemic control while buffering against some GLP-1-induced gastrointestinal distress. It also regulates lipid buffering in white adipose tissue.
Interactive infographics
Clinical endpoint overview
Review key efficacy endpoints from published Phase 2 research. Charts will animate as you scroll them into view.
Comparative context
Endpoint summary
The following table provides a concise view of the primary research themes represented in the published Phase 2 program.
| Research area | Population / window | Reported signal | Interpretive note |
|---|---|---|---|
| Body weight | Adults with obesity or overweight with related conditions; 48 weeks | Up to 24.2% mean body-weight reduction at 12 mg | The 12 mg and 8 mg groups showed steep, dose-responsive trajectories through week 48 without plateauing. |
| Hepatic fat | NAFLD sub-study; 24 and 48 weeks | Up to 86.0% relative liver fat reduction at 48 weeks | Glucagon receptor activity is a key reason this endpoint is prominent in the retatrutide program. |
| Liver fat normalization | Participants with elevated liver fat at baseline | Approximately 89% achieving <5% absolute liver fat in selected higher-dose groups | The normalization threshold provides an intuitive view of categorical response for steatosis clearance. |
| Glycemic control | Type 2 diabetes Phase 2 trial; 36 weeks | Up to 2.16% mean HbA1c reduction at 12 mg | Findings were reported against placebo and an active GLP-1 comparator arm (dulaglutide 1.5 mg). |
Dossier tracks
Explore the research narrative
Select a research track below to review mechanism, weight-management outcomes, hepatic endpoints, and supporting source data.
TRIUMPH Phase 3 clinical program
Following the significant velocity of weight reduction in Phase 2, the expansive TRIUMPH Phase 3 clinical development program was initiated to assess long-term safety, efficacy, and cardiovascular outcomes across thousands of global participants.
Key ongoing trials
TRIUMPH-1: Evaluating efficacy and safety in adults with obesity or overweight without type 2 diabetes over 84 weeks.
TRIUMPH-2: Specifically targeting adults with obesity or overweight who also have type 2 diabetes.
TRIUMPH-3: Investigating retatrutide in adults with severe obesity (BMI ≥35) and established cardiovascular disease.
Phase 2 obesity: 48-week data
Design: 48-week, double-blind, randomized, placebo-controlled trial evaluating 338 adults with BMI ≥30, or ≥27 with comorbidities. Doses ranged up to 12 mg weekly.
Outcomes: At 48 weeks, the 12 mg dose achieved a 24.2% mean reduction in body weight. In the 8 mg and 12 mg cohorts, all participants lost at least 5% of baseline body weight, and more than one quarter of participants in the 12 mg cohort lost more than 30%.
Phase 2 type 2 diabetes
Design: 36-week trial evaluating 281 participants with T2D, comparing retatrutide with placebo and dulaglutide 1.5 mg.
Outcomes: The 12 mg cohort demonstrated robust HbA1c reductions (up to 2.16%) combined with unprecedented weight loss for a diabetes-specific cohort, indicating strong dual-purpose efficacy.
NAFLD/MASH-oriented endpoints
Design: A sub-study of the Phase 2 obesity trial focused on 98 patients with nonalcoholic fatty liver disease (NAFLD), recently updated in nomenclature to MASLD.
Outcomes: At 8 mg and 12 mg doses, relative liver fat reductions of 81.4% to 86.0% at 48 weeks were reported, with approximately 89% of participants reaching liver fat normalization below the 5% threshold, largely driven by the glucagon mechanism.
Protocol overview
Step-up titration schedule
A four-step overview of the dose-escalation structure used in the referenced clinical protocols.
Terminology
Glossary of terms
Incretin Hormones
Metabolic hormones (like GLP-1 and GIP) that are released from the gut into the bloodstream in response to food ingestion, helping to lower blood glucose levels by stimulating insulin release and reducing appetite.
Glucagon
A hormone traditionally responsible for raising blood sugar levels. However, in the context of co-agonism (paired with GLP-1/GIP), its activation increases energy expenditure and promotes the breakdown of fats (lipolysis), particularly in the liver.
MASLD / MASH (formerly NAFLD / NASH)
Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) is the accumulation of excess fat in the liver. It can progress to Metabolic Dysfunction-Associated Steatohepatitis (MASH), which involves liver inflammation and damage, potentially leading to fibrosis or cirrhosis.
Researcher FAQ
Frequently asked questions
How does the weight-loss velocity compare to dual-agonists?
In Phase 2 trials, participants on the 12 mg dose of retatrutide lost 24.2% of body weight at just 48 weeks. By comparison, established dual-agonists reached roughly 20.9% at 72 weeks. The addition of the glucagon receptor appears to steepen the trajectory of weight reduction.
What differentiates retatrutide from tirzepatide?
While tirzepatide acts on two receptors (GLP-1 and GIP) focused primarily on intake regulation and insulin sensitivity, retatrutide is a "triple G" agonist that adds the glucagon receptor. This third mechanism actively increases energy expenditure and directly targets hepatic lipid metabolism.
What are the cardiovascular and heart-rate safety implications?
Phase 2 data reported a transient, dose-dependent increase in resting heart rate (typical of glucagon agonism) that peaked around week 24 and began trending toward baseline by week 48. This occurred alongside robust improvements in broader cardiometabolic markers, including significant lipid panel enhancements.
Why is the liver fat endpoint so pronounced?
Glucagon signaling directly promotes lipolysis (fat breakdown) in the liver. When combined with the massive caloric deficit driven by GLP-1/GIP, the liver rapidly sheds ectopic fat, making retatrutide a highly promising investigational agent for MASLD/MASH.
Is skin hyperesthesia a reported side effect?
Mild, transient skin hyperesthesia (increased sensitivity of the skin) was reported in a small percentage of Phase 2 participants, similar to what has been sporadically noted in other incretin programs. Gastrointestinal side effects remain the most common adverse events.
References & source data
- Phase 2 obesity: Jastreboff, A. M., et al. (2023). Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with obesity. The New England Journal of Medicine, 389(6), 514-526. https://doi.org/10.1056/NEJMoa2301972
- Phase 2 type 2 diabetes: Rosenstock, J., et al. (2023). Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes. The Lancet, 402(10401), 529-544. https://doi.org/10.1016/S0140-6736(23)01053-X
- NAFLD/MASH sub-study: Sanyal, A. J., et al. (2024). Retatrutide in patients with non-alcoholic fatty liver disease. Hepatology. Abstract data reference
- TRIUMPH Phase 3 program: ClinicalTrials.gov identifiers: NCT05929066, NCT05882045, NCT05813240. ClinicalTrials.gov