Retatrutide

Retatrutide – Research Peptide

Triple GIP, GLP-1 & Glucagon Receptor Agonist for Scientific Research

Retatrutide (LY3437943) is an investigational peptide and a novel triple receptor agonist designed to activate three metabolically important signaling pathways: the glucose-dependent insulinotropic polypeptide (GIP) receptor, glucagon-like peptide-1 (GLP-1) receptor, and glucagon (GCG) receptor.

This distinctive triple-agonist mechanism has made retatrutide an important subject of scientific investigation in metabolic biology, energy homeostasis, body-weight regulation, glucose metabolism and obesity research.

Unlike single-pathway GLP-1 receptor agonists or dual GIP/GLP-1 receptor agonists, retatrutide combines activity at three hormone receptors within a single molecule. This provides researchers with an opportunity to investigate how simultaneous modulation of these pathways may influence appetite, energy intake, energy expenditure and broader metabolic processes. (New England Journal of Medicine)

ICAME Pharmacy Retatrutide is intended strictly for laboratory research and development purposes. It is not intended for human or veterinary use.

What is Retatrutide?

Retatrutide, also known by its developmental designation LY3437943, is a single peptide engineered to exhibit agonist activity at the:

GIP receptor (GIPR)
GLP-1 receptor (GLP-1R)
Glucagon receptor (GCGR)

These three receptors participate in interconnected physiological pathways involved in nutrient sensing, glucose regulation, appetite and energy balance.

The simultaneous activation of these receptors distinguishes retatrutide from earlier incretin-based compounds and has led to its description as a GIP–GLP-1–glucagon triple receptor agonist. (New England Journal of Medicine)

Triple Receptor Mechanism

GLP-1 Receptor Activity

GLP-1 is an incretin hormone involved in the physiological response to food intake.

Activation of the GLP-1 receptor is associated with several metabolic processes, including glucose-dependent insulin secretion, regulation of glucagon secretion, gastrointestinal signaling and mechanisms affecting appetite and food intake.

For researchers, GLP-1 signaling represents an important pathway for studying energy intake, glucose homeostasis and metabolic regulation.

GIP Receptor Activity

GIP is another nutrient-responsive incretin hormone.

The GIP receptor participates in insulin secretion and broader metabolic signaling. Its interaction with GLP-1 signaling has become an increasingly important area of metabolic research.

Retatrutide's simultaneous activity at both GIP and GLP-1 receptors enables researchers to investigate the interaction between these two incretin pathways while also examining the additional contribution of glucagon receptor activation.

Glucagon Receptor Activity

The third component of retatrutide's mechanism is glucagon receptor agonism.

Glucagon signaling is involved in hepatic glucose metabolism, substrate utilization and energy homeostasis. Researchers have investigated whether incorporating glucagon receptor activity alongside incretin receptor agonism could influence energy expenditure and metabolic regulation beyond what is observed through incretin signaling alone.

The combination of these three pathways is the central scientific concept behind retatrutide. (New England Journal of Medicine)

How Retatrutide Works

In simplified research terms, retatrutide simultaneously engages:

GIPR + GLP-1R + GCGR

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Integrated Metabolic Signaling

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Regulation of Energy Intake • Glucose Metabolism • Energy Expenditure • Body-Weight Homeostasis

Rather than targeting a single metabolic receptor, retatrutide allows researchers to investigate the potential interaction between multiple nutrient-responsive hormonal pathways.

The inclusion of glucagon receptor activity is particularly significant from a research perspective because it introduces mechanisms associated with substrate utilization and energy expenditure alongside the appetite and glucose-related signaling associated with incretin pathways. (New England Journal of Medicine)

Scientific Research on Retatrutide

Retatrutide has progressed through an extensive clinical research program.

A randomized, double-blind, placebo-controlled Phase 2 trial involving 338 adults with obesity or overweight plus a weight-related condition evaluated retatrutide for 48 weeks.

At week 48, mean body-weight changes were:

In the 12 mg group, 83% of participants achieved at least 15% weight reduction during the trial. The investigators also noted that mean weight loss had not clearly plateaued by the end of the 48-week treatment period. (New England Journal of Medicine)

These findings generated considerable scientific interest in triple-receptor agonism as an experimental approach to metabolic research.

Phase 3 Research

Retatrutide subsequently entered Lilly's TRIUMPH Phase 3 clinical development program.

In May 2026, Lilly announced topline results from the Phase 3 TRIUMPH-1 study involving adults with obesity or overweight and at least one weight-related comorbidity without diabetes.

According to the company, participants assigned to 12 mg retatrutide had an average 28.3% body-weight reduction at 80 weeks, while participants in an extension population with baseline BMI ≥35 had an average 30.3% reduction at 104 weeks. These are company-announced Phase 3 results and should be distinguished from the earlier peer-reviewed Phase 2 publication. 

In July 2026, Lilly also reported topline results from TRIUMPH-2 and TRIUMPH-3. In TRIUMPH-2, which studied adults with obesity or overweight and type 2 diabetes, the reported average weight reduction reached 20.8% at 80 weeks at the highest studied dose, alongside reductions in HbA1c. TRIUMPH-3 studied adults with severe obesity and established cardiovascular disease and reported average weight reductions of up to 22.6%.

These findings remain part of an investigational clinical-development program and do not mean that retatrutide is an approved treatment.

Potential Research Areas

Retatrutide is of scientific interest across several areas of metabolic research, including:

• GIP receptor signaling

• GLP-1 receptor signaling

• Glucagon receptor signaling

• Triple receptor agonism

• Metabolic regulation

• Energy homeostasis

• Appetite and food-intake signaling

• Body-weight regulation

• Glucose metabolism

• Insulin signaling research

• Lipid and substrate metabolism

• Obesity-related experimental models

• Cardiometabolic research

• Incretin biology

• Experimental pharmacology

Its multi-receptor activity makes retatrutide particularly interesting for comparative research involving single, dual and triple metabolic receptor agonism.

Retatrutide vs. Other Incretin Research Approaches

From a mechanistic research perspective, compounds in this area can be differentiated by the receptors they target:

GLP-1 receptor agonism
→ GLP-1R

Dual incretin agonism
→ GIPR + GLP-1R

Retatrutide triple agonism
→ GIPR + GLP-1R + GCGR

The addition of glucagon receptor agonism makes retatrutide scientifically distinct from compounds that target GLP-1 alone or GIP and GLP-1 together.

This does not establish clinical superiority; it represents a mechanistic difference that is being investigated through clinical and experimental research.

Safety Findings in Clinical Research

Safety remains an essential component of retatrutide research.

In the published Phase 2 obesity trial, the most commonly reported adverse events were gastrointestinal, and their frequency was dose-related. Most were described as mild to moderate.

Researchers also observed dose-dependent increases in heart rate, which peaked at approximately 24 weeks and subsequently declined. (New England Journal of Medicine)

These findings reinforce why retatrutide remains an investigational compound requiring controlled clinical evaluation.

Product Information

Product Name: Retatrutide
Development Code: LY3437943
Brand: ICAME Pharmacy
Product Category: Research Peptide / Investigational Research Compound
Research Classification: Triple GIP / GLP-1 / Glucagon Receptor Agonist
Research Area: Metabolic Biology / Incretin Research / Energy Homeostasis
Intended Use: Laboratory Research & Development Only

Batch-specific information such as purity, analytical methodology, Certificate of Analysis (COA), batch/lot identification and validated storage conditions should be provided according to the documentation associated with the individual production batch.

Important Research Use Notice

FOR RESEARCH USE ONLY (RUO).

This product is intended exclusively for legitimate laboratory, analytical and scientific research purposes.

Not for human or veterinary use. Not for diagnostic, therapeutic, prophylactic, weight-management or performance-enhancing purposes. Not for direct administration to humans or animals.

Retatrutide is an investigational compound and is not currently an approved medicinal product. Eli Lilly states that it has not been approved by any regulatory agency.

Information presented on this page is intended solely for scientific and educational purposes and should not be interpreted as medical advice, prescribing information or a representation of established clinical safety or efficacy.

About ICAME Pharmacy

ICAME Pharmacy provides specialized research products for professional laboratory and scientific applications.

Our research portfolio focuses on compounds relevant to contemporary areas of molecular, biochemical and metabolic investigation. Product information is presented with an emphasis on responsible research use, scientific transparency and clear product identification.

For batch-specific documentation, analytical information and product inquiries, please contact ICAME Pharmacy.