Apelin
An endogenous peptide hormone that regulates blood pressure, cardiac contractility, and fluid homeostasis through APJ receptor signaling.
Research Status
Research compound
For research purposes only. Not approved for human use. Not medical advice.
Research Areas
Side Effects
Redness, mild swelling, or bruising at injection site. Usually resolves within 24-48 hours. Minimize by rotating sites, using proper injection technique, and allowing solution to reach room temperature.
Temporary drop in blood pressure, particularly with initial doses. May cause dizziness or lightheadedness. Typically mild and self-resolving. Monitor blood pressure, especially if on antihypertensive medications.
Mild to moderate headache reported in some research subjects. Usually transient and resolves within hours. May be related to vasodilation or fluid shifts.
Transient sensation of warmth or flushing, likely due to vasodilation. Typically brief and self-limiting.
Mild water retention or slight weight gain reported in some subjects. Related to apelin's role in fluid homeostasis. Monitor weight and sodium intake.
Occasional mild nausea reported. Usually transient. May be minimized by injecting at consistent times and maintaining adequate hydration.
Apelin enhances insulin sensitivity; users with diabetes or on glucose-lowering medications should monitor blood glucose closely. Risk of low blood sugar if doses are not adjusted appropriately.
Anaphylaxis or severe allergic reaction is rare but possible. Symptoms include difficulty breathing, swelling of face/throat, severe rash, or rapid heartbeat. Seek immediate medical attention if these occur.
Dosing Reference
| Parameter | Value |
|---|---|
| Dose range | 100-300 mcg |
| Frequency | 1-2x daily |
| Timing | Morning and/or evening, consistent timing recommended |
| Route | Subcutaneous |
Research dosing only. Start at lower end (100 mcg) and titrate based on response. Typical research protocols use 100-300 mcg per injection. Exact dosing varies by study design and individual response.
Research disclaimer
Figures drawn from published research literature and community logs. Not clinical recommendations. Consult a qualified professional. Research use only.
Reconstitution Guide
Do not use saline or bacteriostatic saline — use only bacteriostatic water for reconstitution
Do not shake the vial vigorously; gentle swirling prevents peptide degradation
Discard immediately if the solution appears cloudy, discolored, or contains visible particles
Use within 30 days of reconstitution when stored at 2–8°C
Do not freeze the reconstituted solution; freezing may denature the peptide
Use the PeptideVolt reconstitution calculator for your exact concentration
Molecular and Pharmacological Data
| Half-life | Approximately 30-60 minutes in circulation (varies by variant and species) |
| Sequence | QRPRL (apelin-5) or longer variants including apelin-13 (RPRLSHKGPMPF) and apelin-36 |
Apelin is an endogenous peptide hormone that binds to the APJ receptor (a G-protein coupled receptor) to regulate cardiovascular function, blood pressure, and fluid homeostasis. It enhances cardiac contractility, promotes vasodilation through nitric oxide signaling, and modulates the renin-angiotensin-aldosterone system (RAAS). Apelin also plays roles in glucose metabolism, angiogenesis, and anti-inflammatory responses.
APJ Receptor Signaling
Apelin binds to APJ receptors on cardiac myocytes, endothelial cells, and vascular smooth muscle, activating G-protein coupled receptor signaling that increases cardiac contractility and promotes vasodilation
Nitric Oxide (NO) Pathway
APJ activation stimulates endothelial nitric oxide synthase (eNOS), increasing NO production and promoting vascular relaxation and improved blood flow
RAAS Modulation
Apelin inhibits the renin-angiotensin-aldosterone system, reducing vasoconstriction and sodium retention, thereby supporting blood pressure regulation and fluid balance
Angiogenesis and Vascular Development
Apelin promotes new blood vessel formation and vascular stability through APJ signaling on endothelial cells, supporting tissue perfusion and oxygen delivery
Glucose Metabolism
Apelin enhances insulin sensitivity and glucose uptake in skeletal muscle and adipose tissue, potentially through AMP-activated protein kinase (AMPK) activation
- Apelin is a naturally occurring peptide discovered in 1998 as the endogenous ligand for the APJ receptor
- Multiple apelin variants exist (apelin-5, apelin-13, apelin-36) with similar but distinct biological activities
- APJ receptors are widely distributed in the heart, blood vessels, brain, and adipose tissue
- Apelin levels are reduced in heart failure and cardiovascular disease, making it a therapeutic target
- Apelin has both inotropic (increases heart contractility) and vasodilatory effects
- The peptide modulates fluid homeostasis by opposing aldosterone signaling
- Apelin has anti-inflammatory and anti-apoptotic properties in cardiac tissue
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View all peptidesResearch Use Only. All content on this page is provided for informational and educational purposes related to scientific research. Apelin is not approved for human use by the FDA or any equivalent regulatory body. This is not medical advice. Do not use any substance discussed here for therapeutic, diagnostic, or preventative purposes. Consult a qualified healthcare professional before making any health-related decisions. The Peptide Volt does not endorse the use of any research chemicals. 18+ only.