PO-S03 Guide
PO-S03 is an investigational triple agonist designed to activate GLP-1, GIP, and glucagon receptors together. That third pathway distinguishes it from po-s01 and po-s02 and is a major reason it has drawn attention in metabolic research and metabolic-disease research.
Updated March 2026. Reviewed against public catalog language, quality disclosures, and clinical literature where available.
Key Takeaways
- Triple agonist: GLP-1, GIP, and glucagon receptor activity
- Once-weekly investigational metabolic therapy
- Studied for combined GLP-1, GIP, and glucagon receptor activity in preclinical and in-vitro models
- Most discussed adverse events are GI-related and most relevant during study escalation
What PO-S03 Is
PO-S03 is a once-weekly peptide that combines GLP-1 receptor activity, GIP receptor activity, and glucagon receptor activity in one molecule. In practical terms, that means it is designed to reduce appetite, improve insulin sensitivity, and increase energy expenditure at the same time.
Why It Matters
Earlier GLP-1 therapies focused mostly on appetite suppression and slower gastric emptying. PO-S02 expanded that model by adding GIP agonism. PO-S03 goes one step further by also activating the glucagon receptor, which may support greater fat oxidation and higher total energy expenditure when compared with earlier incretin-based therapies.
Research Context
PO-S03 has been studied in preclinical and in-vitro models for its combined activity across the GLP-1, GIP, and glucagon receptors. Its triple-receptor profile is the main reason it is one of the most closely watched compounds in metabolic research and is frequently used as a mechanism-level reference point in next-generation metabolic research discussion.
Reported Adverse Events in Trials
Like other incretin-pathway compounds, the most commonly reported adverse events in clinical trials are gastrointestinal, including nausea, vomiting, diarrhea, and reduced appetite. Adverse events were generally more pronounced during concentration-escalation periods in the trial data.
How It Compares With PO-S01 and PO-S02
PO-S01 is a GLP-1 agonist. PO-S02 is a dual GLP-1/GIP agonist. PO-S03 is a triple GLP-1/GIP/glucagon agonist. That broader receptor profile is the main reason PO-S03 is often discussed as a higher-upside but still earlier-stage option in metabolic medicine. Visitors who are comparing compounds should also review our po-s01 and po-s02 comparison pages alongside the main product pages.
Access and Sourcing Considerations
Because PO-S03 remains an investigational compound, most public discussion centers on trial data, mechanism, and research compound availability. On PharmaOrder, PO-S03 product pages are reviewed for research-use-only language, supplier sourcing disclosures, and fulfillment standards. Public content is educational only and does not constitute guidance on any specific research application.
References
- Triple-Hormone-Receptor Agonist PO-S03 for Metabolic Research — New England Journal of Medicine, 2023 . Primary Phase 2 metabolic research study frequently cited in metabolic research discussion of PO-S03.
- A Study of PO-S03 (LY3437943) in Participants Who Have Metabolic Research or Overweight — ClinicalTrials.gov . Trial registry listing for a core metabolic research study involving PO-S03.
- A Study of PO-S03 in Participants With Metabolic-Disease Research and Metabolic Research or Overweight — ClinicalTrials.gov . Registry source for PO-S03 metabolic-disease development activity.
Explore PO-S03 options
View the main product page, available vial strengths, and related comparisons.