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What is Semaglutide? GLP-1 Receptor Agonist Research Peptide
Updated May 2026 · By the Onyx Biolabs Research Team · For laboratory research use only
Semaglutide is a synthetic 31-amino-acid GLP-1 receptor agonist research peptide engineered for extended half-life and stable receptor activation. It is the most-researched single-receptor GLP-1 agonist and serves as the foundational reference compound for metabolic-disease and obesity preclinical research.
How semaglutide works
Semaglutide is a 31-amino-acid analog of native human GLP-1 (glucagon-like peptide-1), engineered with a fatty-acid side chain that binds albumin in circulation. This albumin binding extends semaglutide’s half-life from minutes (native GLP-1) to approximately 7 days — the foundation for once-weekly research dosing.
At the receptor level, semaglutide binds and activates GLP-1R (GLP-1 receptor). GLP-1R activation increases insulin secretion in response to glucose, suppresses appetite via central nervous system pathways, slows gastric emptying, and reduces glucagon secretion. The combination drives the metabolic effects observed across diabetes and obesity research models.
Semaglutide molecular properties
- Molecular weight: ~4,113 Da (theoretical, 31 amino acids with C18 fatty-acid modification)
- Sequence length: 31 amino acids
- Half-life (preclinical): ~7 days, supporting weekly dosing
- Receptor target: GLP-1R (single agonist)
- 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 — GLP-1 receptor activation is the foundational mechanism studied across diabetes preclinical work
- Obesity research — appetite suppression via central GLP-1 receptors
- Cardiovascular metabolic research — secondary GLP-1 effects on cardiac tissue and vasculature
- Comparative incretin studies — baseline single-agonist compound for comparison with tirzepatide (dual) and retatrutide (triple)
How semaglutide compares to tirzepatide and retatrutide
Semaglutide is the simplest of the three major GLP-1 family peptides studied today: it engages a single receptor (GLP-1). Tirzepatide engages two (GLP-1 + GIP). Retatrutide engages three (GLP-1 + GIP + glucagon). Each additional receptor adds metabolic effects but also adds complexity. For research that isolates GLP-1 receptor effects specifically, semaglutide is the cleanest tool.
Where to source research-grade semaglutide
Onyx Biolabs sells Semaglutide research peptide in 5 mg, 10 mg, 20 mg, and 30 mg vials with verified >99% purity. Every batch is independently tested by Kovera Labs. View current COAs.
Frequently asked questions
What is semaglutide?
Semaglutide is a synthetic 31-amino-acid GLP-1 receptor agonist research peptide. It is the most-studied single-receptor GLP-1 analog and serves as the foundational reference compound for metabolic and obesity preclinical research.
What is the molecular weight of semaglutide?
Approximately 4,113 Daltons (theoretical mass for the 31-amino-acid sequence with C18 fatty-acid modification).
How does semaglutide work?
Semaglutide binds and activates the GLP-1 receptor (GLP-1R). GLP-1R activation increases insulin secretion in response to glucose, suppresses appetite, slows gastric emptying, and reduces glucagon secretion.
How is semaglutide different from tirzepatide?
Semaglutide activates only the GLP-1 receptor. Tirzepatide activates both GLP-1 and GIP receptors (dual agonist). Tirzepatide produces stronger appetite suppression and insulin sensitization because the two incretin pathways amplify each other.
How is semaglutide different from retatrutide?
Semaglutide is a single agonist (GLP-1 only). Retatrutide is a triple agonist (GLP-1 + GIP + glucagon). Retatrutide adds both GIP-driven amplification and glucagon-driven energy expenditure.
What concentration should I reconstitute semaglutide at?
For a 10 mg vial, 2 mL of bacteriostatic water gives 5 mg/mL. For a 30 mg vial, 3 mL gives 10 mg/mL. Use the peptide calculator.
How long does reconstituted semaglutide stay stable?
Approximately 28 days at 2–8°C when reconstituted with bacteriostatic water. Do not freeze reconstituted vials.
Is semaglutide legal to purchase in the United States?
Semaglutide is sold legally in the United States as a research chemical for in-vitro and laboratory research use only.
Where can I buy research-grade semaglutide?
Onyx Biolabs sells semaglutide in 5/10/20/30 mg vials with independent Kovera Labs COAs at /product/semaglutide-peptide/.
Related glossary entries
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.