Retatrutide: The Triple Agonist (GLP-1 + GIP + Glucagon) Mechanism, Phase 2 Trial Data, and the Future of Metabolic Therapy
If tirzepatide's dual-agonist approach looked like a quantum leap over semaglutide, retatrutide makes tirzepatide look like the intermediate step it may well turn out to be. This is the drug that produced weight loss numbers that most obesity researchers thought they would never see from a pill or injection — 24.2% mean weight reduction in Phase 2, before the trial had even reached a plateau. A molecule that targets not two but three hormone receptors simultaneously, combining the metabolic power of GLP-1, GIP, and glucagon in a single weekly injection. It is, if the clinical development goes to plan, the most powerful non-surgical treatment for obesity ever made.
What Is Retatrutide?
Retatrutide (development code: LY3437943) is an investigational drug developed by Eli Lilly and Company. It is a triple hormone receptor agonist — a single synthetic peptide engineered to simultaneously activate three different G-protein coupled receptors:
- GLP-1 receptor (GLP-1R) — the same receptor targeted by semaglutide and tirzepatide
- GIP receptor (GIPR) — the same receptor co-targeted by tirzepatide
- Glucagon receptor (GCGR) — a receptor not targeted by any currently approved obesity or diabetes drug
As of mid-2026, retatrutide is in Phase 3 clinical trials under the TRIUMPH program, with the first Phase 3 results (TRIUMPH-4) reported in December 2025 showing 28.7% weight reduction. FDA approval is anticipated in late 2027, with commercial launch projected for early 2028.
The Three Receptors: Why Each One Matters
GLP-1 Receptor: The Anchor
Retatrutide's GLP-1R component provides the familiar benefits: glucose-dependent insulin secretion, glucagon suppression, gastric emptying delay, and central appetite suppression through the NTS-hypothalamus circuit. GLP-1R agonism is the proven backbone of this drug class — everything else builds on it.
GIP Receptor: The Amplifier
As established with tirzepatide, adding GIPR activation to GLP-1R agonism produces synergistic weight loss, improved insulin sensitivity in adipose tissue through GLUT-4 translocation, and additional CNS satiety signaling through hypothalamic GIP receptors. Retatrutide inherits and extends these benefits from its GIP component.
Glucagon Receptor: The Energy Burner
This is the key differentiator — the addition that no other approved drug includes. Glucagon is the body's primary counter-regulatory hormone to insulin. You know it as the thing that raises blood sugar when you're fasting: glucagon signals the liver to break down glycogen (stored glucose) and release it. That's the classic pharmacology textbook account.
But glucagon has a much larger metabolic role that has been underappreciated clinically — it is also a potent thermogenic and lipolytic agent. Research in Frontiers in Endocrinology documents that glucagon receptor activation:
- Rapidly increases energy expenditure in adult humans — infusion of glucagon at pharmacological doses increases caloric expenditure by up to 230 kcal/day in some studies
- Stimulates lipolysis in white adipose tissue, mobilizing stored triglycerides as free fatty acids
- Directly increases hepatic fatty acid oxidation — the liver actually burns its own fat
- Promotes thermogenesis in brown adipose tissue (BAT) by increasing uncoupling protein expression and mitochondrial oxygen consumption
- Activates the FGF21 pathway — glucagon receptor signaling in the liver triggers secretion of fibroblast growth factor 21, which acts on adipose tissue to further increase thermogenic capacity
In short: glucagon receptor agonism makes the body burn more energy at rest. This is the mechanism that GLP-1 alone and GIP+GLP-1 together fundamentally cannot achieve. Semaglutide and tirzepatide reduce weight primarily by suppressing intake — eating less. Retatrutide adds a second major arm: the body also burns more, even between meals.
The Obvious Problem: Glucagon Raises Blood Sugar
Activating glucagon receptors creates an immediate pharmacological problem. Glucagon's best-known action is increasing hepatic glucose production — exactly what you don't want in a drug for type 2 diabetes or metabolic obesity. Stand-alone glucagon receptor agonism would cause hyperglycemia.
This is where the triple agonism becomes elegant engineering. The GLP-1R component counteracts glucagon's glucose-raising effects by:
- Stimulating glucose-dependent insulin secretion (more insulin absorbs the glucose glucagon releases)
- Suppressing endogenous glucagon secretion from alpha cells
- Reducing hepatic glucose output through improved insulin signaling
The GIP receptor component adds further insulin secretion and insulin-sensitizing effects. The net result in clinical trials: the glucose-raising effects of glucagon receptor activation are effectively neutralized by the GLP-1R and GIPR components, leaving the thermogenic and lipolytic benefits intact without meaningful hyperglycemia.
Retatrutide's Structural Design
Structurally, retatrutide is based on a GIP backbone — similar to tirzepatide — with modifications to the amino acid sequence and addition of a fatty acid chain that enables albumin binding for extended half-life, supporting once-weekly subcutaneous dosing.
The molecule was engineered to activate all three receptors with sufficient potency at each target while maintaining the GLP-1R and GIPR components in appropriate balance to offset glucagon's hyperglycemic liability. This is a significant medicinal chemistry challenge: optimizing a single peptide to be active at three structurally distinct receptors without losing potency at any of them, and without having the glucagon-like effects dominate the glucose-lowering and insulin-stimulating components.
The result is a molecule where the three receptor activities work together to produce a metabolic effect profile unlike anything previously achievable in a single drug: reduced food intake (GLP-1R + GIPR CNS effects) + improved glucose handling (GLP-1R + GIPR pancreatic effects) + increased energy expenditure (GCGR thermogenic effects) + direct hepatic fat oxidation (GCGR liver effects).
Phase 2 Clinical Trial: The NEJM 2023 Landmark
Trial Design
The Phase 2 trial (NCT04881760), published in the New England Journal of Medicine in June 2023 by Jastreboff et al., was a 48-week, randomized, double-blind, placebo-controlled study evaluating retatrutide in 338 adults with obesity or overweight without type 2 diabetes (BMI ≥27 with weight-related conditions).
Participants were randomized to receive retatrutide at doses of 1 mg, 4 mg (two starting-dose sub-groups), 8 mg (two starting-dose sub-groups), or 12 mg, or placebo, administered subcutaneously once weekly for 48 weeks.
Results at 24 Weeks (Primary Endpoint)
Mean percentage change in body weight at 24 weeks, by dose group:
- 1 mg: −7.2%
- 4 mg combined: −12.9%
- 8 mg combined: −17.3%
- 12 mg: −17.5%
- Placebo: −1.6%
Results at 48 Weeks (Secondary Endpoint)
The 48-week data was where retatrutide showed its full potential, as published in the PR Newswire announcement of Lilly's NEJM publication:
- 1 mg: −8.7%
- 4 mg: −17.1%
- 8 mg: −22.8%
- 12 mg: −24.2% (57.8 lbs / 26.2 kg average weight lost)
- Placebo: −2.1%
At 48 weeks, the proportion of participants on 12 mg achieving various weight loss thresholds:
- ≥5% weight loss: 100% (everyone on the highest dose lost at least 5%)
- ≥10% weight loss: 93%
- ≥15% weight loss: 83%
Crucially: the weight loss had not plateaued by week 48. Eli Lilly noted that participants appeared to still be losing weight at study end, suggesting the full weight loss potential of the drug had not yet been achieved. Phase 3 trials with longer duration would be needed to see the eventual plateau.
MASLD (Fatty Liver Disease) Substudy
Perhaps the most dramatic finding from the Phase 2 program wasn't the weight loss — it was what happened to participants' livers. Results from a MASLD substudy were published in Nature Medicine in June 2024, revealing:
- 86% relative reduction in liver fat content at 48 weeks with the 12 mg dose (measured by MRI)
- >85% of participants with baseline NAFLD achieved complete resolution of hepatic steatosis (liver fat below 5%) at 48 weeks with 8 mg and 12 mg doses
- Liver fat reduction of ≥70% was observed in 93% of participants on the 12 mg dose
These numbers dwarf what any other drug has achieved for liver fat. Semaglutide produces roughly 40–50% liver fat reduction. Tirzepatide produces 50–55%. Retatrutide at 12 mg produces 86%. The explanation is the glucagon receptor component: GCGR activation in the liver directly drives hepatic fatty acid oxidation — the liver burns its stored fat in response to glucagon signaling, on top of the systemic fat loss driven by GLP-1/GIP effects. This is a direct, targeted hepatic mechanism that other drugs lack.
Phase 3 TRIUMPH Program
TRIUMPH-4: First Phase 3 Results (December 2025)
The first Phase 3 trial to report was TRIUMPH-4, which enrolled adults with obesity or overweight and moderate-to-severe knee osteoarthritis. Results announced in December 2025 by Eli Lilly:
- Mean weight loss at 68 weeks: 26.4% (9 mg dose) and 28.7% (12 mg dose), vs. 2.1% placebo
- Pain reduction: average 75.8% reduction in WOMAC pain scores
- Participants achieving ≥25% weight loss: 47.7% (9 mg) and 58.6% (12 mg)
- Participants achieving ≥30% weight loss: approximately 28–35% (dose-dependent)
The 28.7% weight loss figure at 68 weeks is the highest ever reported for a pharmacological treatment in a Phase 3 trial — surpassing tirzepatide's 22.5% in SURMOUNT-1.
Remaining TRIUMPH Trials
The TRIUMPH program includes seven Phase 3 trials expected to report throughout 2026:
- TRIUMPH-1: Pivotal obesity trial (~2,300 participants, BMI ≥30), 89-week duration — the centerpiece trial for FDA NDA submission
- TRIUMPH-2: Type 2 diabetes + obesity population
- TRIUMPH-3: Cardiovascular and renal outcomes trial (long-term, event-driven)
- TRIUMPH-5: Obesity + T2D, HbA1c and weight co-primary endpoints
- Additional trials in MASLD, sleep apnea, and maintenance dosing strategies
Regulatory Timeline
Based on current trial status as of mid-2026:
- TRIUMPH trials complete: Q2–Q3 2026
- NDA submission to FDA: Q4 2026 or Q1 2027
- FDA review period: ~10 months
- Projected FDA approval: late 2027
- Projected commercial launch: Q1–Q2 2028
Comparison: Semaglutide vs. Tirzepatide vs. Retatrutide
| Parameter | Semaglutide (Wegovy) | Tirzepatide (Zepbound) | Retatrutide (Investigational) |
|---|
| Receptors targeted | GLP-1R only | GLP-1R + GIPR | GLP-1R + GIPR + GCGR |
| Phase 3 mean weight loss | 14.9% (68 wks) | 20.9% (72 wks) | 24.2% Phase 2 (48 wks); 28.7% Phase 3 (68 wks) |
| Mechanism | Insulin ↑, glucagon ↓, satiety ↑ | All of above + GIP insulin sensitization | All of above + thermogenesis ↑ + hepatic fat oxidation ↑ |
| Energy expenditure effect | Minimal direct effect | Minimal direct effect | Direct thermogenic increase via GCGR |
| Liver fat reduction | ~40–50% | ~50–55% | ~86% (12 mg, 48 wks) |
| Approval status | FDA-approved (2021/2023) | FDA-approved (2022/2023) | Phase 3; projected approval late 2027 |
| GI side effect rate | Moderate | Moderate | Higher (dose-related; 12–18% discontinue for AEs at max dose) |
| Dosing frequency | Once weekly | Once weekly | Once weekly |
| Hypoglycemia risk | Very low (monotherapy) | Very low (monotherapy) | Low (GLP-1/GIP offset glucagon effect) |
Side Effects and Safety Profile
Gastrointestinal Effects
As expected for an incretin-class drug, the most common adverse events with retatrutide are gastrointestinal: nausea, diarrhea, constipation, and decreased appetite. These are dose-related, mostly mild to moderate in severity, and primarily occur during dose escalation.
The Phase 2 NEJM 2023 data notes that starting at a lower initial dose (2 mg rather than 4 mg for the 8 mg maintenance groups) significantly reduced early GI events, which informed the Phase 3 titration protocol design.
A 2025 meta-analysis in Expert Review of Clinical Pharmacology confirmed that retatrutide produces the highest weight loss among GLP-1-based treatments in the studied trials, but also the highest overall side effect rate — particularly at the highest doses. This is the trade-off: more power comes with more GI disruption, at least during dose escalation.
In TRIUMPH-4, discontinuation rates due to adverse events were 12.2% (9 mg) and 18.2% (12 mg), compared to 4% with placebo — meaningfully higher than tirzepatide's trial rates, though still within a range many patients find acceptable given the extraordinary efficacy.
Heart Rate Effects
An interesting observation from Phase 2: retatrutide produced dose-dependent increases in heart rate that peaked at approximately 24 weeks and then declined. This is likely related to the sympathomimetic effects of glucagon receptor activation (glucagon has mild cardiac stimulatory effects). Phase 3 cardiovascular outcome trials will characterize this more fully.
Blood Sugar Balance
As designed, the hyperglycemic effect of glucagon receptor activation appears effectively neutralized by the GLP-1R and GIPR components. Phase 2 data showed meaningful HbA1c reductions in participants with elevated baseline glucose, and in the TRANSCEND-T2D-1 Phase 3 trial reported by Eli Lilly in March 2026, retatrutide reduced HbA1c by 1.7–2.0% at 40 weeks in type 2 diabetes patients, alongside 16.8% weight loss — confirming the triple mechanism successfully balances the glucose effects.
Potential for MASLD and NASH Treatment
Retatrutide may be uniquely positioned among pharmacological treatments for metabolic dysfunction-associated steatotic liver disease (MASLD), formerly NAFLD, and its more severe form MASH (formerly NASH).
The triple receptor mechanism provides three distinct anti-MASLD pathways:
- Weight loss (GLP-1R + GIPR): Significant weight reduction decreases hepatic fat as a consequence of overall fat loss
- Direct hepatic fat oxidation (GCGR): The liver burns its own fat in response to glucagon receptor stimulation — a mechanism independent of systemic weight loss
- Improved insulin sensitivity (GLP-1R + GIPR): Better insulin signaling reduces de novo lipogenesis (new fat production) in the liver
The Phase 2 MASLD substudy published in Nature Medicine 2024 documented 86% liver fat reduction — the largest treatment effect ever reported for liver fat in a pharmacological trial, exceeding resmetirom (the first FDA-approved MASLD drug) and tirzepatide substantially.
For context:
- Resmetirom (Rezdiffra): ~33% liver fat reduction; approved for MASH with fibrosis March 2024
- Tirzepatide: ~50–55% liver fat reduction; FDA review for MASH indication ongoing
- Semaglutide: ~40–50% liver fat reduction
- Retatrutide 12 mg: ~86% liver fat reduction
What Makes Retatrutide the "Next Evolution"
The progression from GLP-1 monotherapy → GLP-1/GIP dual therapy → GLP-1/GIP/glucagon triple therapy represents a coherent pharmacological logic:
Step 1 (Semaglutide): Reduce intake by activating satiety/insulin pathways
Step 2 (Tirzepatide): Add a second satiety/metabolic pathway (GIP) that is synergistic with GLP-1 and operates on partly different cellular populations
Step 3 (Retatrutide): Add energy expenditure and thermogenesis on top of the reduced-intake effects — essentially combining caloric restriction pharmacology with metabolic rate elevation pharmacology in a single molecule
This third step is conceptually important. Most weight loss interventions (including GLP-1 and dual agonists) work primarily by reducing caloric intake. The body responds to intake restriction partly by reducing its metabolic rate — a "metabolic adaptation" that limits the long-term effectiveness of restriction-only approaches. By also increasing energy expenditure through glucagon receptor activation, retatrutide partially counteracts this metabolic adaptation, potentially explaining why the weight loss hasn't plateaued at 48 weeks in Phase 2 and why Phase 3 data at 68–89 weeks shows continued loss.
Frequently Asked Questions
Q: What is retatrutide and how does it differ from tirzepatide?
A: Retatrutide (LY3437943) is an investigational triple hormone receptor agonist developed by Eli Lilly that activates GLP-1R, GIPR, and the glucagon receptor (GCGR) simultaneously. Tirzepatide, by contrast, activates GLP-1R and GIPR only. The addition of glucagon receptor agonism in retatrutide adds thermogenic effects (increased energy expenditure and body heat production) and direct hepatic fat oxidation — mechanisms absent from tirzepatide and all other approved obesity drugs. This third mechanism is believed to explain retatrutide's substantially greater weight loss in clinical trials.
Q: What did the Phase 2 NEJM 2023 trial show for retatrutide?
A: The Phase 2 trial published in the New England Journal of Medicine in June 2023 showed that retatrutide 12 mg weekly produced mean body weight reductions of 17.5% at 24 weeks (primary endpoint) and 24.2% at 48 weeks (secondary endpoint) in adults with obesity without type 2 diabetes. At the 12 mg dose, 100% of participants achieved ≥5% weight loss, 93% achieved ≥10%, and 83% achieved ≥15% — and critically, weight loss had not plateaued at week 48, suggesting Phase 3 trials with longer duration would show even greater losses.
Q: How does glucagon receptor agonism cause weight loss without raising blood sugar?
A: Glucagon receptor activation increases energy expenditure through thermogenesis and lipolysis, which drives weight loss. However, glucagon also raises blood sugar by stimulating hepatic glucose production — a liability for use in diabetic or metabolic patients. Retatrutide counteracts this by simultaneously activating GLP-1R (which stimulates glucose-dependent insulin secretion and suppresses glucagon from alpha cells) and GIPR (which further amplifies insulin secretion and insulin sensitivity). The net effect in clinical trials is glucose-lowering, not glucose-raising, despite the glucagon receptor component being active.
Q: What are retatrutide's Phase 3 TRIUMPH trial results so far?
A: The first Phase 3 result came from TRIUMPH-4, reported in December 2025, which enrolled adults with obesity and knee osteoarthritis. At 68 weeks, the 12 mg dose produced 28.7% mean weight loss — the highest ever reported for any pharmacological treatment in a Phase 3 trial — along with 75.8% reduction in knee pain scores. The pivotal TRIUMPH-1 obesity trial (the primary basis for FDA submission) is expected to report in 2026. All TRIUMPH trials are expected to complete by Q2–Q3 2026, with NDA submission estimated Q4 2026 or Q1 2027.
Q: Is retatrutide FDA-approved?
A: No. As of 2026, retatrutide remains investigational and is only available through clinical trials. It is not FDA-approved for any indication. Based on the Phase 3 trial completion timeline and FDA review periods, approval is projected for late 2027 at the earliest, with commercial launch anticipated in Q1–Q2 2028. Eli Lilly has not yet submitted a New Drug Application.
Q: What makes retatrutide special for fatty liver disease (MASLD)?
A: Retatrutide produced an 86% reduction in liver fat content at 48 weeks in the Phase 2 MASLD substudy — the largest liver fat reduction ever reported for a pharmacological agent, substantially exceeding semaglutide (~40–50%), tirzepatide (~50–55%), and resmetirom (the first approved MASLD drug at ~33%). The glucagon receptor component is the key differentiator: GCGR activation in the liver directly drives hepatic fatty acid oxidation, meaning the liver burns its own stored fat. This is a direct hepatic mechanism on top of the systemic weight loss and improved insulin sensitivity provided by GLP-1R and GIPR activation.
Q: What are the side effects of retatrutide?
A: Like all GLP-1-class drugs, retatrutide's main side effects are gastrointestinal: nausea, diarrhea, constipation, and decreased appetite. These are dose-related and primarily occur during dose escalation, with gradual titration substantially reducing their severity. In TRIUMPH-4, 12.2–18.2% of patients at the highest doses discontinued due to adverse events (vs. 4% with placebo) — a higher discontinuation rate than tirzepatide, reflecting the more powerful pharmacological activity. Retatrutide also causes dose-dependent increases in heart rate that peak around 24 weeks. Phase 3 cardiovascular outcome data will further characterize this.
Q: How does retatrutide affect energy expenditure?
A: Glucagon receptor activation — retatrutide's distinguishing mechanism — increases whole-body energy expenditure through multiple pathways. In the liver, GCGR stimulation increases mitochondrial oxidative phosphorylation and fatty acid oxidation, increasing hepatic metabolic rate. In brown adipose tissue, glucagon stimulates thermogenic gene expression, lipolysis, and oxygen consumption. In white adipose tissue, glucagon promotes lipolysis and may promote "browning." At the systemic level, glucagon infusion has been shown to increase caloric expenditure by up to 230 kcal/day. This thermogenic effect is absent from semaglutide and tirzepatide, which work primarily through intake suppression.
Q: Who would benefit most from retatrutide when it is approved?
A: Retatrutide is likely to be most beneficial for patients who have not achieved adequate results with semaglutide or tirzepatide, who have very high weight loss goals (30%+ body weight reduction), or who have specific metabolic conditions like MASLD/NASH where the direct hepatic fat-burning mechanism offers therapeutic advantages beyond what other drugs provide. Its higher side effect profile at maximum doses means it may be preferentially used in patients with significant metabolic disease burden who need the additional efficacy. Patients with adequate response to tirzepatide may not need to escalate to retatrutide.
Q: What is the expected weight loss with retatrutide in Phase 3 trials?
A: Based on TRIUMPH-4 data at 68 weeks showing 28.7% weight loss (12 mg dose), and Eli Lilly analyst projections that TRIUMPH-1 (the 80-week obesity trial) could potentially exceed 30% weight loss due to the longer duration, retatrutide may establish a new upper boundary for pharmacological weight loss in the 25–30%+ range. Phase 2 data showed no plateau at 48 weeks, suggesting the weight loss continues accumulating. The pivotal TRIUMPH-1 data, expected in 2026, will provide the definitive answer.
Q: Does retatrutide work for type 2 diabetes?
A: Yes. The TRANSCEND-T2D-1 Phase 3 trial reported in March 2026 showed retatrutide reduced HbA1c by 1.7–2.0% at 40 weeks and produced 16.8% body weight loss in type 2 diabetes patients — meeting all primary and key secondary endpoints. The GLP-1R and GIPR components provide robust insulin secretion and sensitivity effects, while the glucagon component's glucose-raising effects are effectively neutralized by the other two receptor activities. Multiple Phase 3 trials in T2D are ongoing under the TRANSCEND program.
Key Takeaways
- Retatrutide is the first triple hormone receptor agonist: activating GLP-1R + GIPR + GCGR simultaneously in a single weekly injection.
- The glucagon receptor (GCGR) component is the key differentiator: it adds thermogenesis, lipolysis, and direct hepatic fat oxidation — mechanisms completely absent from all other obesity drugs.
- Glucagon's hyperglycemic effects are offset: the GLP-1R and GIPR components counteract GCGR's glucose-raising effect, producing net glucose-lowering in clinical trials.
- Phase 2 NEJM 2023: 24.2% mean weight reduction at 48 weeks at the 12 mg dose — with weight loss still accumulating and no plateau observed.
- TRIUMPH-4 Phase 3 (Dec 2025): 28.7% mean weight loss at 68 weeks — the highest ever in a Phase 3 pharmacological obesity trial.
- Liver fat reduction is unprecedented: 86% relative reduction at 12 mg (48 weeks), compared to ~40–55% for currently approved drugs.
- Phase 3 TRIUMPH program: 7+ trials expected to complete in 2026; NDA submission projected Q4 2026/Q1 2027; FDA approval expected late 2027.
- Higher side effect profile than tirzepatide: greater GI adverse events and higher discontinuation rates at maximum doses — the cost of the additional mechanism.
- The "next evolution": retatrutide represents the first drug to combine reduced-intake pharmacology (GLP-1/GIP) with increased-expenditure pharmacology (glucagon) — a fundamentally different and more comprehensive approach to obesity pharmacotherapy.
Citations & References
- Jastreboff AM et al. "Triple-Hormone-Receptor Agonist Retatrutide for Obesity — A Phase 2 Trial." NEJM. 2023 Jun 26. https://pubmed.ncbi.nlm.nih.gov/37366315/
- Eli Lilly. "Phase 2 retatrutide results published in NEJM — 24.2% mean weight reduction." PR Newswire. 2023. https://www.prnewswire.com/news-releases/lillys-phase-2-retatrutide-results-published-in-the-new-england-journal-of-medicine-show-the-investigational-molecule-achieved-up-to-17-5-mean-weight-reduction-at-24-weeks-in-adults-with-obesity-and-overweight-301863690.html
- Eli Lilly. "TRIUMPH-4: Retatrutide achieves 28.7% weight loss in Phase 3." PR Newswire. 2025 Dec 11. https://www.prnewswire.com/news-releases/lillys-triple-agonist-retatrutide-delivered-weight-loss-of-up-to-an-average-of-71-2-lbs-along-with-substantial-relief-from-osteoarthritis-pain-in-first-successful-phase-3-trial-302638804.html
- Eli Lilly. "TRANSCEND-T2D-1 Phase 3 Results." 2026 Mar 19. https://lilly.gcs-web.com/news-releases/news-release-details/lillys-triple-agonist-retatrutide-demonstrated-significant
- Jastreboff AM et al. (MASLD substudy). "Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease." Nature Medicine. 2024 Jun 10. https://www.nature.com/articles/s41591-024-03018-2
- TRIUMPH Phase 3 Program Overview. Lola Health. 2026. https://lolahealth.com/blogs/longevity/retatrutide-clinical-trials
- Patel R et al. "Efficacy and safety of triple hormone receptor agonist retatrutide for obesity." Expert Review of Clinical Pharmacology. 2025 Jan–Feb. https://pubmed.ncbi.nlm.nih.gov/39817343/
- American Diabetes Association Meeting News. "Phase 2 trial results demonstrate benefits of retatrutide in obesity, T2DM, NASH." 2023. https://www.adameetingnews.org/phase-2-trial-results-demonstrate-benefits-of-retatrutide-in-obesity-type-2-diabetes-nash/
- Krieger JP. "Is Glucagon Receptor Activation the Thermogenic Solution for Obesity?" Frontiers in Endocrinology. 2022. https://www.frontiersin.org/journals/endocrinology/articles/10.3389/fendo.2022.868037/full
- Whitticar N et al. "Glucagon Regulation of Energy Expenditure." International Journal of Molecular Sciences. 2019. https://pmc.ncbi.nlm.nih.gov/articles/PMC6862306/
- Clinical Trials Arena. "Lilly's triple G agonist boasts 28.7% weight loss in Phase III trial." Dec 2025. https://www.clinicaltrialsarena.com/news/lilly-retatrutide-data-phase-iii-trial/
- PubMed. "Is retatrutide (LY3437943) a GLP-1, GIP, and glucagon receptor agonist...?" 2023. https://pubmed.ncbi.nlm.nih.gov/37086147/
- RetaWeightLoss.com. "When Will Retatrutide Be FDA Approved? 2026 Timeline Update." 2026. https://www.retaweightloss.com/article/when-will-retatrutide-be-fda-approved-2026-timeline-update
- Moonshot Medical. "Retatrutide & Fatty Liver: Remarkable MASLD Trial Data." 2026. https://moonshotmp.com/learn/retatrutide/fatty-liver-masld/
