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What is Tirzepatide? Dual Agonist Research Peptide Explained
Updated May 2026 · By the Onyx Biolabs Research Team · For laboratory research use only
Tirzepatide (LY3298176) is a synthetic 39-amino-acid dual agonist research peptide that activates two metabolic receptors simultaneously: GLP-1 and GIP. It was the first dual GLP-1 / GIP agonist studied in clinical research and remains the benchmark for dual-incretin metabolic-research applications.
How tirzepatide works
Tirzepatide is a 39-amino-acid peptide engineered to bind and activate both the GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide) receptors. Both are incretin hormones — gut-derived peptides that drive insulin release in response to glucose. Activating both receptors simultaneously produces synergistic effects on insulin secretion, gastric emptying, and appetite regulation that are stronger than activating either receptor alone.
Tirzepatide is engineered with a fatty-acid side chain that binds albumin in circulation, extending its half-life to approximately 5 days. This supports once-weekly dosing in research protocols. In preclinical models, dual GLP-1/GIP agonism produces stronger appetite suppression than single GLP-1 agonism (semaglutide), making tirzepatide a workhorse compound in metabolic-disease research.
Tirzepatide molecular properties
- Molecular weight: ~4,814 Da (theoretical, 39 amino acids with C20 fatty-acid modification)
- Sequence length: 39 amino acids
- Half-life (preclinical): ~5 days, supporting weekly dosing
- Receptor targets: GLP-1R, GIPR
- Storage: Lyophilized at room temperature short-term, freezer (-20°C) long-term; reconstituted at 2–8°C for ~28 days
Research applications
- Type 2 diabetes models — dual agonism produces strong insulin sensitization in preclinical work
- Obesity research — appetite suppression is more pronounced than single-receptor analogs
- Gastric emptying studies — tirzepatide slows gastric emptying via GLP-1 receptor activity
- Comparative incretin research — commonly studied alongside semaglutide (single agonist) and retatrutide (triple agonist)
How tirzepatide compares to semaglutide and retatrutide
Tirzepatide sits in the middle of the GLP-1 family complexity tree. Semaglutide activates one receptor (GLP-1). Tirzepatide activates two (GLP-1 + GIP). Retatrutide activates three (GLP-1 + GIP + glucagon). Each additional receptor adds metabolic effects: GIP synergizes with GLP-1 for stronger appetite suppression; glucagon adds energy expenditure. The trade-off is metabolic complexity — more receptors mean more variables to control in research.
Where to source research-grade tirzepatide
Onyx Biolabs sells Tirzepatide research peptide in 10 mg, 15 mg, 30 mg, and 60 mg vials with verified >99% purity. Every batch is independently tested by Kovera Labs. View current COAs.
Frequently asked questions
What is tirzepatide?
Tirzepatide (development code LY3298176) is a synthetic 39-amino-acid peptide that simultaneously activates both the GLP-1 and GIP receptors. It is the first dual GLP-1 / GIP agonist studied in metabolic research and is widely used in obesity and diabetes preclinical models.
What is the molecular weight of tirzepatide?
Approximately 4,814 Daltons (theoretical mass for the 39-amino-acid sequence with C20 fatty-acid modification). On a Mass Spec report, the observed mass should match this within +/- 1 Da.
How is tirzepatide different from semaglutide?
Semaglutide activates only the GLP-1 receptor. Tirzepatide activates both GLP-1 and GIP receptors. In research, tirzepatide produces stronger appetite suppression and insulin sensitization than semaglutide because the two incretin pathways amplify each other.
How is tirzepatide different from retatrutide?
Tirzepatide is a dual agonist (GLP-1 + GIP). Retatrutide is a triple agonist (GLP-1 + GIP + glucagon). The added glucagon agonism in retatrutide increases energy expenditure, which tirzepatide does not do.
What concentration should I reconstitute tirzepatide at?
For a 15 mg vial, 2 mL of bacteriostatic water gives 7.5 mg/mL. For a 30 mg vial, 3 mL gives 10 mg/mL. Use the peptide calculator.
How long does reconstituted tirzepatide stay stable?
Approximately 28 days at 2–8°C when reconstituted with bacteriostatic water. Do not freeze reconstituted vials.
Is tirzepatide legal to purchase in the United States?
Tirzepatide is sold legally in the United States as a research chemical for in-vitro and laboratory research use only. It is not approved by the FDA for human consumption.
Where can I buy research-grade tirzepatide?
Onyx Biolabs sells tirzepatide in 10/15/30/60 mg vials with independent Kovera Labs COAs at /product/tirzepatide-peptide/.
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Disclaimer
For research, laboratory, or analytical use only. The compound discussed is not approved for human or animal consumption. Statements on this page have not been evaluated by the FDA. Onyx Biolabs is a chemical supplier, not a compounding pharmacy or 503A/503B facility.