Overview
Ipamorelin is one of the most studied growth hormone-releasing peptides (GHRPs) in modern peptide research. First developed by Novo Nordisk in the late 1990s, it has gained significant attention for its selective mechanism and favorable safety profile compared to other GHRPs. This comprehensive FAQ addresses the most common questions researchers and practitioners have about this peptide.
Basic Questions
1. What is Ipamorelin?
Ipamorelin is a synthetic pentapeptide (five amino acids) that functions as a growth hormone secretagogue. It belongs to the class of growth hormone-releasing peptides (GHRPs) and mimics the action of ghrelin, the body's natural hunger hormone, by binding to the ghrelin receptor (GHSR) in the pituitary gland.
Unlike broad-spectrum secretagogues, Ipamorelin is notable for its selectivity—it stimulates growth hormone release without significantly affecting cortisol, prolactin, or aldosterone levels.
2. What is the molecular structure of Ipamorelin?
| Property | Value |
|---|---|
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| Molecular Formula | C₃₈H₄₉N₉O₅ |
| Molecular Weight | 711.85 Da |
| CAS Number | 170851-70-4 |
| Type | Pentapeptide |
The "Aib" (aminoisobutyric acid) at the N-terminus and D-amino acids contribute to its resistance to enzymatic degradation.
3. How was Ipamorelin discovered?
Ipamorelin was developed by Novo Nordisk in the 1990s through structure-activity relationship studies aimed at finding more selective growth hormone secretagogues. It emerged from research comparing numerous GHRP variants, with Ipamorelin standing out for its unique selectivity profile.
4. What makes Ipamorelin different from other GHRPs?
Ipamorelin's primary distinguishing feature is its selectivity. While other GHRPs like GHRP-6 and GHRP-2 stimulate growth hormone release effectively, they also elevate cortisol, prolactin, and trigger significant hunger responses. Ipamorelin achieves comparable GH release without these additional effects, making it the "cleanest" GHRP available.
Mechanism of Action
5. How does Ipamorelin work?
Ipamorelin works through multiple complementary mechanisms:
- Ghrelin Receptor Binding: Binds to GHSR (growth hormone secretagogue receptor) in the anterior pituitary
- GH Release Stimulation: Triggers the release of stored growth hormone from somatotroph cells
- Amplification: Enhances the pulsatile release pattern of endogenous GH
- Somatostatin Modulation: May reduce somatostatin's inhibitory effects on GH release
Importantly, Ipamorelin works with the body's natural feedback mechanisms rather than overriding them, which contributes to its favorable safety profile.
6. Does Ipamorelin affect other hormones?
One of Ipamorelin's key advantages is what it doesn't do. Research has consistently shown:
- No significant cortisol increase (unlike GHRP-6 and GHRP-2)
- No prolactin elevation (unlike GHRP-2)
- Minimal to no appetite stimulation (unlike GHRP-6)
- No effect on aldosterone (unlike other GHRPs)
This selectivity means fewer unwanted side effects and a cleaner hormonal response.
7. How does Ipamorelin compare to natural GH release?
Ipamorelin stimulates GH release in a pulsatile manner that more closely mimics the body's natural secretion pattern compared to exogenous GH administration. Rather than creating a constant elevated GH level, it amplifies the normal pulse amplitude, preserving the physiological rhythm that is important for optimal GH effects.
Dosing and Administration
8. What is the typical research dosing protocol?
Standard research protocols typically use:
| Protocol | Dose | Frequency |
|---|---|---|
| Conservative | 100 mcg | 2-3x daily |
| Standard | 200 mcg | 2-3x daily |
| Advanced | 300 mcg | 2-3x daily |
Most research suggests that doses above 300 mcg per administration provide diminishing returns for GH release.
9. What is the optimal timing for administration?
Timing significantly impacts Ipamorelin's effectiveness:
Optimal Times:
- Morning (fasted): Upon waking, before eating
- Pre-workout: 15-30 minutes before exercise
- Post-workout: During the anabolic window
- Before bed: To enhance natural nocturnal GH pulse
Timing Considerations:
- Administer on an empty stomach (at least 2 hours after eating)
- Avoid food for 20-30 minutes after administration
- Blood glucose and fatty acids inhibit GH release, so fasting enhances effects
10. Does food affect Ipamorelin's effectiveness?
Yes, significantly. Elevated blood glucose and free fatty acids blunt the GH response to Ipamorelin. Research shows optimal results when administered:
- At least 2 hours after a meal
- With no food consumption for 20-30 minutes post-administration
- Away from high-fat or high-carbohydrate meals
11. How is Ipamorelin administered?
Ipamorelin is typically administered via subcutaneous injection. The peptide comes as a lyophilized (freeze-dried) powder that must be reconstituted with bacteriostatic water before use.
Reconstitution Steps:
- Allow vial to reach room temperature
- Add bacteriostatic water slowly along the vial wall
- Gently swirl—never shake
- Store reconstituted solution refrigerated at 2-8°C
12. How long does reconstituted Ipamorelin remain stable?
When properly stored at 2-8°C (refrigerated) with bacteriostatic water, reconstituted Ipamorelin typically remains stable for:
- With bacteriostatic water: 4-6 weeks
- With sterile water: 3-7 days
Lyophilized (unreconstituted) Ipamorelin can be stored at room temperature but maintains longer stability when refrigerated.
Stacking and Combinations
13. What is the Ipamorelin + CJC-1295 stack?
The combination of Ipamorelin with CJC-1295 (without DAC) is the most researched and popular peptide stack for growth hormone optimization. These peptides work synergistically:
- CJC-1295: A GHRH analog that extends the duration of GH release
- Ipamorelin: A GHRP that amplifies the pulse amplitude
Together, they can produce GH elevations 3-5 times greater than either peptide alone.
14. Why does this stack work so well?
The synergy comes from their complementary mechanisms:
- CJC-1295 stimulates GH release via the GHRH receptor pathway
- Ipamorelin stimulates GH release via the ghrelin receptor pathway
- Both pathways converge on the somatotroph cells but through different signaling cascades
- The combined effect is multiplicative rather than merely additive
This dual-pathway stimulation explains the substantial enhancement in GH output.
15. What is the typical dosing for the stack?
Common research protocols for the combination:
| Component | Dose | Frequency |
|---|---|---|
| Ipamorelin | 100-200 mcg | 2-3x daily |
| CJC-1295 (no DAC) | 100-200 mcg | 2-3x daily |
Both peptides are typically administered simultaneously in the same injection for convenience.
16. Can Ipamorelin be stacked with other peptides?
Ipamorelin can be combined with various peptides depending on research goals:
- BPC-157/TB-500: For tissue repair studies
- Tesamorelin: Another GHRH analog (though CJC-1295 is more common)
- MK-677: Oral GH secretagogue (note: may be redundant given similar mechanism)
Avoid stacking with other GHRPs (GHRP-6, GHRP-2) as they compete for the same receptor.
Effects and Benefits
17. What are the primary research applications?
Ipamorelin research has focused on several areas:
| Application | Research Status |
|---|---|
| Body composition | Well-documented |
| Sleep quality | Established |
| Recovery and repair | Promising |
| Bone mineral density | Emerging |
| Anti-aging markers | Early research |
| Muscle protein synthesis | Documented |
18. What changes can be expected in body composition?
Research suggests Ipamorelin's GH-stimulating effects may support:
- Increased lipolysis (fat mobilization)
- Enhanced lean body mass preservation
- Improved muscle recovery post-exercise
- Better nitrogen retention
Effects on body composition are typically gradual, becoming more apparent over 8-12 weeks of consistent use.
19. How does Ipamorelin affect sleep?
One of the most consistently reported effects of Ipamorelin is improved sleep quality. This is attributed to:
- Enhanced nocturnal GH secretion (GH naturally peaks during deep sleep)
- Potential effects on sleep architecture
- Increased slow-wave sleep duration
Many users report falling asleep faster, deeper sleep, and more vivid dreams.
20. How long until effects become noticeable?
Timeline of commonly reported effects:
| Timeframe | Expected Changes |
|---|---|
| Week 1-2 | Improved sleep quality, recovery |
| Week 3-4 | Enhanced energy, workout recovery |
| Week 6-8 | Body composition changes begin |
| Week 12+ | More significant recomposition |
Safety and Side Effects
21. What are the common side effects?
Ipamorelin is generally well-tolerated, with most reported side effects being mild and transient:
Common (typically resolve quickly):
- Injection site reactions (redness, slight pain)
- Mild water retention initially
- Transient headache
- Facial flushing post-injection
Less Common:
- Slight dizziness
- Tingling or numbness (temporary)
22. What about hunger stimulation?
Unlike GHRP-6, which strongly stimulates appetite through ghrelin receptor activation, Ipamorelin produces minimal to no hunger response. This is due to its selective binding profile that preferentially activates GH release without triggering the appetite-related ghrelin pathways.
This makes Ipamorelin more suitable for research involving body composition where appetite control is important.
23. Are there concerns about cortisol elevation?
No. One of Ipamorelin's distinguishing features is that it does not significantly elevate cortisol levels, even at higher doses. Research comparing GHRPs found that while GHRP-2 and GHRP-6 caused dose-dependent cortisol increases, Ipamorelin showed no such effect.
This is particularly relevant for long-term research protocols where chronic cortisol elevation would be problematic.
24. Does Ipamorelin cause prolactin elevation?
No. Unlike GHRP-2, which can elevate prolactin levels, Ipamorelin does not significantly affect prolactin secretion. This eliminates concerns about prolactin-related side effects that can occur with other GHRPs.
25. Can Ipamorelin suppress natural GH production?
Unlike exogenous GH administration, Ipamorelin works with the body's natural feedback systems rather than bypassing them. Research suggests:
- No evidence of pituitary GH depletion with appropriate dosing
- Preserved endogenous GH pulsatility
- Recovery of baseline function after cessation
That said, cycling protocols are commonly employed as a precautionary measure.
Contraindications and Precautions
26. Who should not use Ipamorelin?
Absolute contraindications include:
- Active malignancy: GH can stimulate tumor growth
- Pregnancy/breastfeeding: Insufficient safety data
- Diabetic retinopathy: GH may worsen eye complications
- Intracranial hypertension: Can be exacerbated by GH
Relative contraindications (require careful consideration):
- Uncontrolled diabetes
- Severe sleep apnea
- History of cancer (discuss with oncologist)
- Carpal tunnel syndrome
27. Are there drug interactions to consider?
Ipamorelin may interact with:
- Glucocorticoids: May diminish GH response
- Insulin: GH has anti-insulin effects
- Thyroid medications: GH can affect T4 to T3 conversion
- Other GH-affecting substances: May cause unpredictable effects
Always document concurrent medications in research protocols.
28. What is the regulatory status of Ipamorelin?
| Jurisdiction | Status |
|---|---|
| FDA (USA) | Not approved for human use |
| WADA | Prohibited (S2: Peptide Hormones) |
| Research Use | Available as research chemical |
Ipamorelin is currently available for research purposes only and has not received approval from any major regulatory body for therapeutic use.
Practical Considerations
29. What is the typical cycle length?
Common research protocols:
| Protocol Type | Duration | Notes |
|---|---|---|
| Standard | 8-12 weeks | Most common |
| Extended | 12-16 weeks | With monitoring |
| Maintenance | Ongoing | Lower doses, periodic breaks |
Many researchers implement "5 days on, 2 days off" or "3 weeks on, 1 week off" patterns, though continuous use is also researched.
30. How does Ipamorelin compare to synthetic GH?
| Factor | Ipamorelin | Exogenous GH |
|---|---|---|
| Administration | 2-3x daily injection | 1x daily injection |
| GH Pattern | Pulsatile (natural) | Constant elevation |
| Feedback Preservation | Yes | No (suppressive) |
| IGF-1 Elevation | Moderate | High |
| Cost | Lower | Higher |
| Side Effect Profile | Generally milder | More significant |
| Research for Dosing | Standardized | Complex titration |
Comparison with Other GHRPs
GHRP-6 vs. Ipamorelin
| Characteristic | GHRP-6 | Ipamorelin |
|---|---|---|
| GH Release | Strong | Moderate-Strong |
| Hunger Stimulation | Severe | Minimal |
| Cortisol Increase | Yes | No |
| Prolactin Increase | Yes | No |
| Selectivity | Low | High |
GHRP-2 vs. Ipamorelin
| Characteristic | GHRP-2 | Ipamorelin |
|---|---|---|
| GH Release | Strongest | Moderate-Strong |
| Hunger Stimulation | Moderate | Minimal |
| Cortisol Increase | Yes | No |
| Prolactin Increase | Yes | No |
| Selectivity | Low | High |
Key Takeaways
- Selectivity is Ipamorelin's primary advantage—comparable GH release without affecting cortisol, prolactin, or appetite
- Best results with CJC-1295 (no DAC) due to synergistic dual-pathway stimulation
- Timing matters—administer fasted for optimal GH response
- Generally well-tolerated with mild, transient side effects
- Not approved for human use—available for research purposes only
- Preserves natural GH pulsatility unlike exogenous GH administration
References
- Raun K, et al. "Ipamorelin, the first selective growth hormone secretagogue." European Journal of Endocrinology (1998)
- Johansen PB, et al. "Ipamorelin: a new GH secretagogue with unique binding properties." Growth Hormone & IGF Research (1999)
- Jiménez-Reina L, et al. "Pharmacological profile of ipamorelin." Journal of Endocrinological Investigation (2002)
- Anderson LL, et al. "Growth hormone secretagogues: structure-activity relationships." Endocrine Reviews (2004)
- Sinha DK, et al. "Beyond the androgen receptor: GH and IGF-1 signaling." Reviews in Endocrine & Metabolic Disorders (2018)
This article is for educational and research purposes only. Ipamorelin is not approved for human therapeutic use by any regulatory authority. Researchers should ensure compliance with all applicable regulations and institutional guidelines.