GEP-44 (Chimeric GLP-1/Y1/Y2 Multi-Agonist)
Also known as: GEP44, Doyle Group chimeric peptide, GLP-1/Y1/Y2 triple agonist
Overview
GEP-44 is a 44-amino-acid chimeric peptide developed in the laboratory of Robert Doyle at Syracuse University, in collaboration with the Blevins/Roth groups at the VA Puget Sound and University of Washington. It is a multi-receptor agonist designed to activate the GLP-1 receptor (GLP-1R) together with two peptide YY receptors, Y1 (NPY1R) and Y2 (NPY2R). In rodent and shrew models published between 2021 and 2025, GEP-44 produced greater reduction in body weight and energy intake than the GLP-1-only reference compound exendin-4, with substantially less emesis-like behavior in shrews — the standard animal model for GLP-1-induced nausea. A GLP-1R knockout study published in 2024 showed that GEP-44's metabolic effects in mice depend primarily on GLP-1R signaling, with the Y1R and Y2R arms modulating rather than substituting for the GLP-1 signal. A 2025 energy expenditure follow-up showed weight loss was driven by reduced food intake and increased lipid oxidation, while energy expenditure on the drug was actually decreased. As of May 2026, GEP-44 is preclinical — there is no active IND filing, no registered Phase 1 trial on ClinicalTrials.gov, and no human safety or efficacy data. The current formulation requires once-daily subcutaneous injection; the Syracuse team has stated it is working on a long-acting reformulation. A sister compound, KCEM1, comes from the same program. Both compounds have generated preclinical signals in obesity, type 2 diabetes, and opioid-craving models.
Mechanism of Action
GEP-44 binds and activates three class B G-protein-coupled receptors: GLP-1R (glucagon-like peptide 1 receptor), Y1R (neuropeptide Y receptor type 1), and Y2R (neuropeptide Y receptor type 2). The published mechanistic work supports a signal-biased model in which Y1R agonism partially antagonizes one branch of GLP-1R downstream signaling — specifically the branch implicated in GLP-1-induced nausea — while leaving the appetite-suppressing and glycemic-control branches intact. The 2024 GLP-1R knockout study established that the metabolic readouts (body weight, energy intake, fasting glucose, core temperature) are GLP-1R-dependent. The Y1R/Y2R arms appear to tune the GLP-1 signal rather than provide an independent additive weight-loss mechanism. This design philosophy differs from the additive multi-agonist class (retatrutide, survodutide) which stacks GIP and glucagon agonism onto a GLP-1 backbone for additive efficacy.
Potential Benefits
- Multi-receptor signal-bias design aimed at decoupling weight loss from nausea
- Outperformed exendin-4 on body weight reduction in diet-induced obese rats
- Near-absence of emesis in shrew models vs exendin-4
- Reduces fasting blood glucose in diet-induced obese mice via GLP-1R
- Preclinical signal in opioid-seeking behavior models (per Syracuse team interviews)
Dosage Protocols
The following reflects doses used in published research studies. This is not medical advice. Consult a qualified healthcare professional.
| Beginner | Investigational only — not available outside trial |
| Intermediate | Investigational only — not available outside trial |
| Advanced | Investigational only — not available outside trial |
| Cycle Duration | Animal studies ran 3 to several days; chronic human dosing not characterized |
GEP-44 is not commercially available. Patients seeking GLP-1 therapy should consult their physician about FDA-approved options (semaglutide, tirzepatide, liraglutide, dulaglutide).
Use our Reconstitution Calculator to determine exact syringe units for your protocol.
Routes of Administration
Subcutaneous injection Not characterized in humans
Animal studies used once-daily subcutaneous dosing. The Syracuse team has stated it is working on a long-acting reformulation that has not been disclosed in published data.
Read our full Routes of Administration Guide for detailed comparison of all delivery methods.
Reconstitution
| Storage | Per future trial protocol |
|---|
No legitimate reconstitution protocol exists outside future FDA-authorized trials.
Need exact syringe measurements?
Amino Acid Sequence
44-amino-acid chimeric peptide; full sequence is published in Brierley et al. 2021 supplementary material
Side Effects & Safety
- Preclinical only — no human safety data
- GI tolerability in shrew models substantially better than exendin-4; relevance to humans unknown
- Decreased energy expenditure observed in rats — may limit long-term efficacy as the body adapts
- Daily-injection formulation may produce injection-site reactions in eventual human trials (not yet characterized)
Safety & Contraindications
This information is for educational purposes only. Consult a qualified healthcare provider before using any peptide.
Preclinical investigational only
FDA Safety Information
GEP-44 is not approved by the FDA for any indication. No human safety profile exists. Any product sold under this name is not the published academic compound and has no quality control linking it to the peer-reviewed source material.
Pharmacokinetics
| Half-Life | Not publicly characterized; current formulation requires once-daily injection in animal studies |
|---|---|
| Storage | Per future clinical trial protocol |
Synergistic Compounds
The following compounds have been studied alongside GEP-44 (Chimeric GLP-1/Y1/Y2 Multi-Agonist) for potential complementary or synergistic effects:
Learn More
References & Further Reading
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