Next-Gen
Retatrutide Protocol
The first triple-hormone agonist engineered for intensive metabolic upregulation and targeted adipose research — GLP-1, GIP, and Glucagon simultaneously.
Triple-Agonist Mechanism
Simultaneous signalling across three critical metabolic pathways — a first in peptide research.
GLP-1 Pathway
Targets satiety centres in the brain, inducing profound appetite suppression and optimising insulin secretion and glucose-dependent response.
GIP Pathway
Enhances lipid buffering and protects metabolic flexibility while supporting cellular energy balance and reducing fat accumulation.
Glucagon Pathway
The thermogenic switch. Directly increases basal metabolic rate, stimulates white adipose browning, and elevates hepatic fat oxidation.
The Evolution of Agonists
How Retatrutide advances beyond first and second-generation metabolic compounds.
Semaglutide → Tirzepatide → Retatrutide
| Feature | Semaglutide | Tirzepatide | Retatrutide |
|---|---|---|---|
| Receptor Targets | 1 — GLP-1 | 2 — GLP-1 / GIP | 3 — GLP / GIP / GCG |
| Appetite Suppression | Moderate | High | Maximum |
| Thermogenic Effect | Minimal | Low–Moderate | High (via Glucagon) |
| Body-composition Potency | Standard | Advanced | Extreme |
| Metabolic Lift | Moderate | High | Maximum |
Compound Profile
Identity at a glance.
| Property | Detail |
|---|---|
| Code name | LY3437943 (Eli Lilly) |
| Structure | 39-residue peptide built on the GIP sequence, with a C20 fatty diacid side chain for albumin binding; about 4.73 kDa |
| Receptor profile | Agonist at GIP, GLP-1 and glucagon receptors — most potent at the GIP receptor, with lower relative potency at the GLP-1 and glucagon receptors1 |
| Half-life | About 6 days, supporting once-weekly administration |
| Status (September 2026) | Investigational — phase 3 TRIUMPH programme reporting; not approved anywhere |
Published Research
Peer-reviewed studies behind retatrutide.
| Study | What it found |
|---|---|
| 2022 — Discovery | Lilly described retatrutide’s design and first human data, showing dose-dependent weight loss and glucose lowering.1 |
| 2022 — Phase 1b in type 2 diabetes | Multiple ascending doses were generally well tolerated and lowered glucose and body weight in people with type 2 diabetes.2 |
| 2023 — Phase 2 in obesity (NEJM) | Mean weight loss reached 24.2% at 48 weeks at the highest dose, against 2.1% with placebo.3 |
| 2023 — Phase 2 in type 2 diabetes (Lancet) | Retatrutide produced clinically meaningful reductions in HbA1c and body weight compared with placebo and dulaglutide.4 |
| 2024 — Liver fat (Nature Medicine) | In a phase 2a substudy of people with fatty liver disease, liver fat fell substantially, returning to the normal range in most participants on the higher doses.5 |
Phase 3 Results (2025–2026)
The TRIUMPH and TRANSCEND programmes.
| Trial | Headline result |
|---|---|
| TRIUMPH-4 — December 2025 | In adults with obesity and knee osteoarthritis, mean weight loss was 28.7% at 68 weeks at the highest dose. |
| TRANSCEND-T2D-1 — March 2026 | In adults with type 2 diabetes, mean weight loss was 16.8% at 40 weeks at the highest dose. |
| TRIUMPH-1 — May 2026 | In 2,339 adults with obesity, mean weight loss at 80 weeks was 17.6%, 23.7% and 25.0% across the three dose levels, against 3.9% with placebo. A subgroup with BMI ≥35 who continued for 104 weeks reached up to about 30%. |
| Safety signals | Gastrointestinal effects were the most common adverse events. Dysaesthesia (abnormal skin sensation) was reported in 5.1–12.5% of participants on retatrutide versus 0.9% on placebo, mostly mild to moderate. |
| Still to come | TRIUMPH-2 (obesity with type 2 diabetes) and TRIUMPH-3 (obesity with cardiovascular disease) are due to report later in 2026. |
Evidence Quality & Limitations
Retatrutide’s phase 3 results have so far been released mainly as company announcements and conference presentations, and full peer-reviewed publications are still to come. No head-to-head trial against tirzepatide had been published as of September 2026, so claims that it is “superior” rest on cross-trial comparisons, which are unreliable. The dysaesthesia signal is new to this class and is still being characterised. Ratings such as “Maximum” and “Extreme” in the comparison table above are qualitative, not measured.
References
- Coskun T, et al. LY3437943, a novel triple glucagon, GIP, and GLP-1 receptor agonist for glycemic control and weight loss: from discovery to clinical proof of concept. Cell Metab. 2022;34:1234–47. PubMed
- Urva S, et al. 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. Lancet. 2022;400:1869–81. PubMed
- Jastreboff AM, et al. Triple-hormone-receptor agonist retatrutide for obesity — a phase 2 trial. N Engl J Med. 2023;389:514–26. PubMed
- Rosenstock J, et al. Retatrutide, a GIP, GLP-1 and glucagon receptor agonist, for people with type 2 diabetes: a randomised, double-blind, placebo and active-controlled, parallel-group, phase 2 trial conducted in the USA. Lancet. 2023;402:529–44. PubMed
- Sanyal AJ, et al. Triple hormone receptor agonist retatrutide for metabolic dysfunction-associated steatotic liver disease: a randomized phase 2a trial. Nat Med. 2024;30:2037–48. PubMed
Technical FAQ
Questions researchers ask most often.
Is Retatrutide superior to Tirzepatide?
In research models, the addition of the Glucagon agonist component allows for significantly higher caloric expenditure compared to dual-agonists alone. The thermogenic pathway activation represents a meaningful advancement in metabolic research.
What is the stability of the compound?
Retatrutide is lyophilized for maximum molecular stability. It requires reconstitution with Bacteriostatic Water prior to use. Store dry powder in a cool, dark environment and refrigerate once reconstituted.
What dosing protocol is used in research?
Research protocols typically follow a titrated once-weekly administration schedule to systematically monitor subject response to the triple-agonist signalling cascade before progressing to higher dose ranges.
