Apelin-13
A natural heart hormone that helps your cardiovascular system work better and supports healthy blood flow throughout your body.
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Typical dose
30 nmol/min
Compound profile
Scientific & efficacy data
Healing & Recovery
Peptide profile
Moderate human trials
Apelin-13
30 nmol/min · Once daily
Molecular formula
C69H111N23O16S
- Mol. weight
- 1550.8 Da
- CAS number
- Not yet assigned (research compound)
- PubChem
- 25078060
- Developed · 1998
- Research Team
Academic Research Institutions
Amino acid sequence
Sequence not publicly available or proprietaryDosing
How much do I take?
30 nmol/min · continuous infusion
30 nmol/min
Continuous infusion
Covers all 3 documented dose levels · timing · dose-adjustment guidance.
Suitability
Is this right for me?
Best for research into cardiovascular health and heart function & understanding how the body naturally protects the heart
Best for
Research into cardiovascular health and heart function
Apelin-13 is particularly well-suited for individuals focused on research into cardiovascular health and heart function. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [4][7].
Understanding how the body naturally protects the heart
Apelin-13 is particularly well-suited for individuals focused on understanding how the body naturally protects the heart. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [3].
Exploring potential treatments for heart failure
Apelin-13 is particularly well-suited for individuals focused on exploring potential treatments for heart failure. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [4][7].
Studying mechanisms of heart muscle strength
Apelin-13 is particularly well-suited for individuals focused on studying mechanisms of heart muscle strength. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach [4].
Consider alternatives if
Do not use if
Use with caution if
Not sure?
Compare Apelin-13 with similar peptides to find the best fit for your goals.
Administration
How do I use it?
Intravenous (IV) · Intraarterial
Route
Subcutaneous injection (into the fatty tissue just under the skin)—allows for consistent absorption and can be self-administered at home after proper training
Best sites
Covers reconstitution · step-by-step technique · storage · a sample daily schedule.
Safety
Is it safe?
9 common side effects · 1 serious
Apelin-13 is a research compound with no human clinical trials or FDA approval.
All safety data comes from animal studies and in vitro mechanistic work showing beneficial effects on vascular function and cardiac remodeling. However, animal models do not predict human safety, and the peptide's effects on immune regulation in humans remain untested.
No dose-ranging studies, pharmacokinetics, or organ accumulation data exist in humans. The APJ receptor is expressed in multiple tissues including brain, raising concerns about off-target neurological effects at high doses.
Evidence consists entirely of animal studies in mice, rats, and larger mammals, plus in vitro receptor binding and vascular biology research. No human pharmacokinetics, toxicology screening, Phase 1 safety studies, or clinical efficacy trials have been conducted.
The literature base is mechanistic rather than empirical safety data.
Common side effects · experienced by some users
Mild changes in blood pressure
Mild changes in blood pressure
Management: Consult your healthcare provider for guidance.
Minimal systemic effects in animal studies
Minimal systemic effects in animal studies
Management: Consult your healthcare provider for guidance.
Headache (theoretical, based on blood pressure effects)
Headache (theoretical, based on blood pressure effects)
Management: Consult your healthcare provider for guidance.
Flushing or warmth at injection site
Flushing or warmth at injection site
Management: Consult your healthcare provider for guidance.
Mild inflammation at injection site
Mild inflammation at injection site
Management: Consult your healthcare provider for guidance.
Dizziness if blood pressure drops too quickly
Dizziness if blood pressure drops too quickly
Management: Consult your healthcare provider for guidance.
Allergic reactions to the peptide
Allergic reactions to the peptide
Management: Consult your healthcare provider for guidance.
Heart rhythm changes (requires monitoring)
Heart rhythm changes (requires monitoring)
Management: Consult your healthcare provider for guidance.
Blood pressure, heart rate, cardiac function
Blood pressure, heart rate, cardiac function
Management: Consult your healthcare provider for guidance.
Stop and seek help if
- Severe or worsening side effects that don't improve with dose adjustment or supportive care
- Signs of an allergic reaction—rash, hives, swelling, or difficulty breathing
- Your healthcare provider recommends discontinuation based on your clinical response
- Development of any new medical condition that may be contraindicated with Apelin-13
- Pregnancy or planning to become pregnant (unless specifically approved for use during pregnancy)
- Abnormal lab results or clinical markers that suggest adverse effects
Apelin-13 should only be started, adjusted, or discontinued under medical supervision. This information is for educational purposes only and does not replace professional medical advice. Never stop a prescribed treatment without consulting your healthcare provider first, as abrupt discontinuation may have consequences.
With other peptides
- Safe:APJ receptor agonist research compounds — May be used together under medical guidance.
- Safe:Studies on angiotensin II regulation (cardiovascular balance) — May be used together under medical guidance.
- Safe:Mitochondrial health research (heart energy production) — May be used together under medical guidance.
With medications
- Caution:Other heart-active peptides without proper spacing and monitoring — Use with caution—discuss with your healthcare provider.
- Caution:ACE inhibitors or ARBs (blood pressure medication - requires careful monitoring) — Use with caution—discuss with your healthcare provider.
- Caution:Stimulant compounds that raise heart rate significantly — Use with caution—discuss with your healthcare provider.
With supplements
- Safe:Multivitamins — Generally safe to take alongside Apelin-13. Space doses apart if taking oral formulations to ensure optimal absorption.
- Safe:Electrolyte supplements — Helpful if experiencing any GI side effects that could lead to dehydration. Safe to combine.
Effectiveness
How do I know it's working?
Moderate human trials · first signs minutes (immediate)
Evidence level
Moderate human trials
(Phase 1-2)
Regulatory status
Research compound
Onset of effects
Moderate
(1-2 weeks)
How it works
The deeper mechanism
Apelin-13 is the 13-amino acid C-terminal fragment of apelin that activates the APJ receptor, a G-protein coupled receptor. [5][7] APJ activation increases cardiac contractility, promotes vasodilation, and reduces vascular permeability.
In heart failure models, apelin signaling improves cardiac function and reduces hypertrophy. [7]
What to expect
Minutes (Immediate)
What you might notice
- Heart rate and blood pressure changes begin;
- APJ receptor activation starts;
- initial cardiac contractility increases
What's normal
- Initial response to Apelin-13 is beginning at the cellular level
- Different individuals experience Apelin-13's onset at different rates
- Transient systemic effects from initial Apelin-13 exposure are common
What's next
- Maintain consistent Apelin-13 administration as prescribed
- Document subjective effects and physical markers daily
- Schedule a check-in with your provider about initial observations
Hours (Short-term)
What you might notice
- Peak effects on blood vessel relaxation;
- improved blood flow throughout the body;
- anti-inflammatory signaling begins
What's normal
- Apelin-13 is achieving sufficient receptor engagement
- Initial mechanism of Apelin-13 is taking effect
- Early transient effects from Apelin-13 administration are resolving
What's next
- Maintain consistent Apelin-13 administration as prescribed
- Document subjective effects and physical markers daily
- Schedule a check-in with your provider about initial observations
Days to Weeks (Repeated Dosing)
What you might notice
- Adaptive cardiovascular responses;
- improved heart muscle function with regular use;
- potential protective effects building up
What's normal
- Apelin-13 response patterns are emerging
- Initial Apelin-13 response is consistent with mechanism expectations
- Early tolerance development to Apelin-13 is not expected
What's next
- Assess whether Apelin-13 response aligns with expectations
- Plan next steps based on initial Apelin-13 tolerance and response
- Establish baseline monitoring for Apelin-13 response tracking
Signs it's working
Treatment Response
- Improvement in the primary symptoms or condition being treated
- Positive changes in relevant lab values or clinical markers
- Consistent, stable response to Apelin-13 over time
- Reduction in symptom frequency or severity
General Well-being
- Improved energy levels and daily functioning
- Better quality of life related to the treated condition
- Manageable or absent side effects indicating good tolerance
- Positive feedback from healthcare provider during check-ups
Not seeing results? Common reasons
- Not at therapeutic dose yet—initial doses are for building tolerance, not maximum effect
- Insufficient time at target dose—most compounds need several weeks to show full benefits
- Inconsistent dosing schedule—regular, consistent use is crucial for optimal results
- Individual variation in response—genetics, metabolism, and other factors affect outcomes
- Underlying conditions or medications interfering with absorption or effectiveness
- Improper storage leading to degraded product—always verify proper storage conditions
Key research
Questions
Frequently asked
What does Apelin-13 do in your body?
Apelin-13 is a natural hormone that makes your heart stronger and helps your blood flow better. It sends messages to your heart cells telling them to pump more efficiently and helps your blood vessels relax so blood can move through them more easily. It's like a natural boost for your cardiovascular system [4][7].
Is Apelin-13 approved by the FDA?
No, not yet. Apelin-13 is still in the research stage. Scientists are studying it in laboratories and on animals to understand how it works and how safe it is. It's not available as a medicine for people to use outside of approved clinical research studies [7].
How is Apelin-13 different from Apelin-36?
Apelin-13 and Apelin-36 are different lengths of the same peptide. Apelin-13 is shorter and often works faster and is easier for the body to use. Apelin-36 is longer and might stay active in your body longer. Both activate the APJ receptor, but scientists often prefer studying Apelin-13 because it's more manageable to work with [5][7].
What is the APJ receptor?
The APJ receptor is like a lock on your heart cells that apelin-13 is the key for. When apelin-13 binds to APJ receptors, it starts a chain of events inside the cell that improves heart function. This receptor was discovered in 1993, but scientists didn't find its natural key (apelin) until 1998 [5][6].
Could Apelin-13 help with heart disease?
That's the big question scientists are investigating right now. Early studies show promise that apelin-13 could help protect damaged hearts and improve heart function. However, much more research is needed before it can be used to treat people with heart disease. Several research teams are working on modified versions of apelin-13 that might be safer and more effective for patients [4][7].
Further reading
History & related research
History · since 1998
The heart-strengthening peptide discovered in cow stomachs that could revolutionize heart failure treatment
Apelin-13 is a 13 amino acid peptide that powers up your heart's pumping strength. First discovered in 1998 from bovine stomach tissue, it was originally searching for a home until scientists found its receptor APJ.
Read the full history of Apelin-13Ready for the protocol?
Every dosing tier, administration route, timing note, and dose-adjustment rule for Apelin-13, on one page.