What is GLP-3?
GLP-3 is the research designation for a triple-receptor agonist that simultaneously targets GIP (glucose-dependent insulinotropic polypeptide), GLP-1 (glucagon-like peptide-1), and glucagon receptors. This tripartite mechanism builds on the dual-agonist compounds that came before it, adding a glucagon receptor pathway focused on energy expenditure rather than appetite or insulin signaling alone.
What GLP-3 Is
GLP-3 belongs to a class of research compounds known as multi-receptor incretin agonists. Where first-generation compounds like semaglutide activate only the GLP-1 receptor, and second-generation dual agonists (such as our GLP-2) activate both GIP and GLP-1 receptors, GLP-3 extends this further by adding glucagon receptor agonism — making it a triple agonist.
The rationale behind triple-receptor designs is mechanistic: each additional receptor pathway contributes a distinct piece of metabolic regulation. GIP and GLP-1 are both incretin hormones involved in glucose-dependent insulin secretion and appetite signaling, while the glucagon receptor operates on a separate axis tied to hepatic glucose output and energy expenditure. Combining all three in a single molecule allows researchers to study their interactions without needing to co-administer multiple compounds.
Mechanism of Action
GLP-3's research interest centers on the interplay between three distinct receptor pathways:
GIP receptor: The glucose-dependent insulinotropic polypeptide receptor is activated in a glucose-dependent manner, influencing insulin secretion and contributing to adipose tissue metabolism and energy balance — areas that remain active research questions.
GLP-1 receptor: This is the most extensively studied incretin pathway. GLP-1 receptor activation slows gastric emptying, suppresses glucagon secretion from the pancreas, and reduces appetite signaling through both central (hypothalamic) and peripheral mechanisms.
Glucagon receptor: This is the pathway that distinguishes GLP-3 from dual-agonist compounds. Glucagon receptor activation promotes hepatic glucose output and is associated with increased energy expenditure through thermogenic mechanisms — a research angle that dual GIP/GLP-1 agonists do not address.
Research Applications
GLP-3 is most commonly used in research investigating the additive or synergistic effects of combining incretin and glucagon receptor pathways:
| Research Area | Focus | Why GLP-3 |
|---|---|---|
| Triple-receptor pharmacology | Receptor binding & signaling studies | Allows study of all three pathways from a single compound |
| Energy expenditure | Comparative metabolic research | Glucagon pathway adds a thermogenic component absent from dual agonists |
| Comparative agonist studies | Dual vs triple agonist outcomes | Pairs with GLP-2 (dual agonist) as an experimental/control comparison |
| Extended-protocol research | Larger-format dosing studies | 30mg and 60mg sizes support longer research timelines |
The 60mg format in particular is intended for extended research protocols where larger total compound quantities are needed without frequent vial changes.
GLP-3 vs Dual-Agonist Compounds
The clearest way to understand GLP-3 is in comparison to a dual GIP/GLP-1 agonist such as our GLP-2. Both compounds share the GIP and GLP-1 receptor mechanisms; GLP-3 adds the glucagon receptor as a third pathway. For a full side-by-side comparison — including a receptor profile breakdown, research use-case guidance, and handling differences — see our GLP-3 vs GLP-2 comparison guide.
Reconstitution for Research
GLP-3 is supplied as a lyophilized (freeze-dried) powder and must be reconstituted with Bacteriostatic Water before use in research protocols.
Standard protocol: For 10mg, add 1mL BAC Water (10mg/mL). For 20mg, add 2mL (10mg/mL). For 30mg, add 3mL (10mg/mL). For the 60mg vial, add 3mL BAC Water for a 20mg/mL concentration — a sterile transfer vial may be needed at this concentration. Inject BAC Water slowly down the vial wall and swirl gently; do not shake. The solution should be clear and colorless. Refrigerate at 2-8°C after reconstitution. Stable 28-42 days.
For full reconstitution parameters and a dosing calculator that computes exact draw volumes, visit our Reconstitution Guide and Dosing Calculator.