Peptide Name
Ipamorelin
Updated February 2026
Ipamorelin Dosing Protocol
Complete ipamorelin research dosing protocol with community-derived schedule (100-300 mcg), reconstitution math, selectivity profile, and clinical trial references.
Half-life
~2 hours
Dose range
100-300 mcg per injection
Status
Not FDA-approved
Developer
Novo Nordisk (original)
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Quick Reference Card
Aliases
NNC 26-0161
Category / Class
GH Secretagogue (GHRP)
Half-Life
~2 hours (IV PK data, Gobburu et al. 1999)
Dosing Frequency
1-3 times daily (subcutaneous)
Dose Range
100-300 mcg per injection
Common Vial Sizes
2mg, 5mg, 10mg
Route of Administration
Subcutaneous (SubQ)
Regulatory Status
Not FDA-approved; research compound. Phase II trials were discontinued for postoperative ileus due to lack of efficacy.
Developer
Novo Nordisk (original development)
Key Stat
Most selective GHRP identified - stimulates GH release without affecting cortisol, ACTH, or prolactin at doses up to 200x the GH ED50 (Raun et al. 1998).
What Is Ipamorelin?
Ipamorelin (NNC 26-0161) is a synthetic pentapeptide growth hormone secretagogue and one of the most widely used growth hormone-releasing peptides in the research peptide community. It was originally developed by Novo Nordisk in the late 1990s and is classified as a selective ghrelin or growth hormone secretagogue receptor (GHS-R1a) agonist that stimulates pulsatile growth hormone release from the anterior pituitary.
Structurally, Ipamorelin consists of five amino acids with the sequence Aib-His-D-2-Nal-D-Phe-Lys-NH2. It was derived from GHRP-1 through chemistry optimization that removed the central Ala-Trp dipeptide and produced a smaller compound with improved selectivity. The peptide includes non-standard amino acids that support receptor specificity and metabolic stability, while plasma half-life remains approximately 2 hours.
What makes Ipamorelin unique among GHRPs is selectivity. Unlike GHRP-2 and GHRP-6, it does not significantly stimulate ACTH or cortisol, even at doses far above GH-effective ranges, and it does not materially elevate prolactin, FSH, LH, or TSH in characterization data. Novo Nordisk's clinical development later focused on postoperative ileus rather than GH-related indications, and the program was discontinued after Phase II trials did not show efficacy advantage for that endpoint.
Ipamorelin is now widely available as a research compound and is commonly used in investigational protocols targeting GH optimization, body composition, recovery, and anti-aging research contexts.
This compound is not FDA-approved for any indication. All information on this page is for educational and research reference purposes only.
How Ipamorelin Works: Selective GH Secretagogue Receptor Activation
Ipamorelin stimulates endogenous GH secretion through selective ghrelin receptor signaling while minimizing hormonal cross-reactivity compared with other GHRPs.
Ghrelin / GHS-R1a Receptor Binding
Ipamorelin binds GHS-R1a receptors in the hypothalamus and anterior pituitary, activating intracellular signaling pathways including cAMP and protein kinase A. This stimulates somatotroph cells to release GH in pulsatile episodes that align with physiological secretion dynamics.
Somatostatin Modulation
Ipamorelin appears to reduce somatostatin inhibitory tone on GH release, creating a more permissive environment for GH pulses, especially during natural GH nadir windows. This is one reason timing around bedtime is commonly used in protocols.
Downstream IGF-1 Signaling
The GH pulses induced by Ipamorelin drive downstream hepatic IGF-1 production. IGF-1 is associated with protein synthesis, lipolysis support, tissue repair signaling, and bone-metabolism pathways. Importantly, these effects remain subject to normal hypothalamic-pituitary feedback controls.
Selectivity Advantage
A key differentiator is what Ipamorelin does not do: at GH-effective doses and at high multiples above ED50, characterization studies reported no significant ACTH, cortisol, prolactin, or aldosterone rise. This clean hormonal profile is the primary reason it is often preferred over GHRP-2 and GHRP-6.
In protocol design, this selective profile is balanced with the compound's short half-life, which makes meal timing and injection cadence central variables for maximizing GH pulse quality.
Ipamorelin Dosing Protocol & Schedule
Assessment
Week 1
100 mcg/day
1x daily at bedtime to assess tolerance. Inject in a fasted state.
Titration
Weeks 2-3
200 mcg/day
Use 1x bedtime dose or split 100 mcg 2x/day. Monitor headache and water retention.
Standard Protocol
Weeks 4-8
200-300 mcg/day
Common maintenance range. Frequency is typically 1-2x/day (AM fasted plus bedtime).
Extended Protocol
Weeks 9-12
200-300 mcg/day
Continue if tolerated. Some clinician-guided protocols extend to week 16.
Off-Cycle
4 weeks
0 mcg
Common cycling model after 8-12 weeks on to reduce desensitization risk.
Important Titration Notes
Evidence level: Ipamorelin dosing for GH optimization, body composition, and anti-aging remains community-derived and is not FDA-approved. Trial data mainly supports PK and safety context.
Titration pacing: Start at 100 mcg/day in week 1. Practical protocol consensus places a dose-response plateau near 300 mcg per injection.
Fasting requirement: Inject on an empty stomach (commonly at least 1-2 hours post-meal), and wait roughly 20-30 minutes before eating. Insulin response can blunt GH pulse amplitude.
Dose flexibility: 200 mcg bedtime-only is the most common base protocol. Split dosing (for example AM plus PM) is used when targeting sustained daily pulse coverage.
Missed dose and cycle length: Skip missed doses and resume the next scheduled time; do not double-dose. Typical cycles run 8-12 weeks with a 4-week off period.
Ipamorelin Reconstitution Guide
Vial Size: 2mg
BAC Water: 1.0 mL
Concentration: 2,000 mcg/mL
100 mcg: 0.05 mL (5 units)
200 mcg: 0.10 mL (10 units)
300 mcg: 0.15 mL (15 units)
Vial Size: 5mg
BAC Water: 2.0 mL
Concentration: 2,500 mcg/mL
100 mcg: 0.04 mL (4 units)
200 mcg: 0.08 mL (8 units)
300 mcg: 0.12 mL (12 units)
Vial Size: 10mg
BAC Water: 3.0 mL
Concentration: 3,333 mcg/mL
100 mcg: 0.03 mL (3 units)
200 mcg: 0.06 mL (6 units)
300 mcg: 0.09 mL (9 units)
Step-by-Step Reconstitution Instructions
- Allow the ipamorelin vial to reach room temperature for 5-10 minutes before mixing.
- Clean the ipamorelin vial stopper and BAC water vial stopper with separate alcohol swabs.
- Draw the planned BAC water volume using a sterile syringe.
- Inject the BAC water slowly down the inside wall of the peptide vial.
- Gently swirl or roll the vial until dissolved. Do not shake aggressively.
- Confirm the solution is clear and colorless with no particles.
- Label the vial with concentration and date, refrigerate at 2-8C, and use within 28 days.
Ipamorelin Side Effects - What Research Shows
Ipamorelin is generally considered one of the better tolerated GHRPs because of its selective hormonal profile, though side effects can still occur.
Common side effects: Community protocols most often report mild headache, transient water retention or bloating, and mild appetite increase.
Clinical tolerability context: In Beck et al. 2014 postoperative ileus trial context, treatment-emergent adverse event rates were not worse than placebo.
GH-related effects: At higher doses or extended use, some reports describe mild joint stiffness, tingling in extremities, or transient fatigue consistent with elevated GH/IGF-1 signaling.
Injection site reactions: Temporary redness, stinging, or minor swelling can occur. Site rotation and sterile technique reduce frequency.
Cortisol and hormonal cross-reactivity: Unlike GHRP-2 and GHRP-6, ipamorelin characterization data did not show meaningful ACTH/cortisol/prolactin elevation at GH-effective dosing ranges.
Contraindications and monitoring: Avoid use in active malignancy, uncontrolled glycemic disease, severe cardiovascular disease, and pregnancy or breastfeeding. Consider periodic fasting glucose and HbA1c monitoring for extended protocols. Ipamorelin and ghrelin mimetics are prohibited substances under WADA anti-doping rules.
Ipamorelin Clinical Trial Results
Raun et al. 1998 (Eur J Endocrinol)
Preclinical / early characterization • In vitro and in vivo animal models
Rats and swine
Defined ipamorelin as a selective GH secretagogue with no ACTH/cortisol elevation at high multiples above GH-effective dose.
Gobburu et al. 1999 (Pharm Res)
Phase I (PK/PD) • Single-dose escalation
40 healthy male volunteers
Dose-proportional PK; terminal half-life approximately 2 hours; peak GH around 0.67 hours with finite pulse response.
Beck et al. 2014 (Int J Colorectal Dis)
Phase II • Up to 7 days
117 bowel resection patients (NCT00672074)
Ipamorelin 0.03 mg/kg IV twice daily was generally well tolerated but did not show efficacy superiority for postoperative ileus endpoint.
ClinicalTrials.gov NCT01280344
Phase II • Program period
Postoperative ileus
Study registered for GI function recovery; development program was discontinued after lack of efficacy signal for POI indication.
Ipamorelin clinical development was limited and indication-specific. Early characterization and human PK work established selective GH secretagogue behavior and short half-life, but later Phase II studies targeted postoperative ileus rather than GH optimization. Safety and tolerability signals were acceptable in that context, yet efficacy was not demonstrated for the GI endpoint, and development stopped. No clinical trials have evaluated ipamorelin for body composition, anti-aging, or performance outcomes.
Storage & Handling
Lyophilized (powder)
-20C (-4F)
Long-term storage (years)
Lyophilized (powder)
2-8C (36-46F)
Months
Lyophilized (powder)
Room temperature
Weeks (shipping window)
Reconstituted (liquid)
2-8C (36-46F)
Up to 28 days
Reconstituted (frozen aliquots)
-20C (-4F)
3-4 months
Protect reconstituted solution from light, avoid repeated freeze-thaw cycles, use bacteriostatic water for multi-dose handling, and discard any solution that appears cloudy, discolored, or particulate.
Ipamorelin vs. GHRP-6 vs. GHRP-2
Receptor Target
Ipamorelin: GHS-R1a
GHRP-6: GHS-R1a
GHRP-2: GHS-R1a
Half-Life
Ipamorelin: ~2 hours
GHRP-6: ~20-30 minutes
GHRP-2: ~25-30 minutes
Dosing Frequency
Ipamorelin: 1-3x daily (SubQ)
GHRP-6: 2-3x daily (SubQ)
GHRP-2: 2-3x daily (SubQ)
Standard Dose
Ipamorelin: 200-300 mcg/injection
GHRP-6: 100-300 mcg/injection
GHRP-2: 100-300 mcg/injection
GH Release Potency
Ipamorelin: Comparable to GHRP-6
GHRP-6: Reference standard
GHRP-2: Higher potency than GHRP-6
Cortisol Elevation
Ipamorelin: None in characterization data
GHRP-6: Yes
GHRP-2: Yes
Prolactin Elevation
Ipamorelin: None
GHRP-6: Minimal
GHRP-2: Moderate
Appetite Stimulation
Ipamorelin: Mild
GHRP-6: Strong
GHRP-2: Moderate
FDA Status
Ipamorelin: Not approved
GHRP-6: Not approved
GHRP-2: Not approved
Unique Advantage
Ipamorelin: Most selective GHRP hormonal profile
GHRP-6: Strong appetite stimulation
GHRP-2: High GH potency per mcg
These compounds target the same receptor family but differ in endocrine spillover profiles. Ipamorelin's defining feature is GH release without the cortisol, ACTH, and prolactin elevation commonly associated with GHRP-2 and GHRP-6.
GHRP-6 may be preferred where appetite stimulation is desirable, while GHRP-2 is often selected for GH potency per microgram despite cleaner-profile tradeoffs.
Reconstitution concentration and syringe math differ by vial and protocol. Verify concentration-specific draws before administration.
See the GHRP-6, GHRP-2, CJC-1295 (with DAC) and CJC-1295 (No DAC) for compound-specific guides.
Ipamorelin Stacking Protocols
Stack 1
CJC-1295 (No DAC) + Ipamorelin
A common stack combining CJC-1295 (Mod GRF 1-29) with ipamorelin to target complementary GHRH and GHS-R1a pathways.
A frequently cited protocol model uses 100 mcg CJC-1295 plus 200 mcg ipamorelin together at bedtime in a single SubQ injection.
View stack protocolStack 2
Ipamorelin + BPC-157 Recovery Stack
Some protocols pair ipamorelin GH/IGF-1 signaling support with BPC-157 tissue-repair research context.
See the compound-specific See BPC-157 protocol for additional context.
View stack protocolFrequently Asked Questions - Ipamorelin
Q1: What is the starting dose of Ipamorelin?
The standard starting dose is 100 mcg per injection, usually once daily at bedtime in a fasted state for approximately one week before increasing to 200 mcg. For custom vial concentrations, use https://www.peppal.app/calculator.
Q2: What is Ipamorelin's half-life?
Ipamorelin has a terminal plasma half-life of about 2 hours in human PK data, with GH peaking near 0.67 hours and typically returning toward baseline within a few hours.
Q3: What results can be expected from Ipamorelin?
Clinical trials have not evaluated body-composition or performance endpoints. Community reports often note early sleep-quality changes, while composition or recovery-related changes are variable and protocol-dependent.
Q4: How do you reconstitute Ipamorelin?
Common reconstitution setups are 1 mL BAC water for 2 mg, 2 mL for 5 mg, and 3 mL for 10 mg, with slow wall injection and gentle swirling. See the reconstitution section and calculator at https://www.peppal.app/calculator.
Q5: Is Ipamorelin FDA-approved?
No. Ipamorelin is not FDA-approved for any indication. It advanced to Phase II trials for postoperative ileus and was discontinued for lack of efficacy in that indication. It is also prohibited under WADA anti-doping rules, and FDA categorization has been discussed in 503A/503B compounding frameworks.
Q6: What are the most common side effects of Ipamorelin?
The most commonly reported effects are mild headache, temporary water retention or bloating, and mild appetite increase. GH-related symptoms can occur with higher dose or prolonged protocols.
Q7: How does Ipamorelin compare to GHRP-6 and GHRP-2?
All three are ghrelin receptor agonists, but ipamorelin is generally considered more selective, with lower cortisol and prolactin cross-reactivity in characterization data than GHRP-6 or GHRP-2.
Q8: What vial sizes is Ipamorelin available in?
Research suppliers most commonly offer 2 mg, 5 mg, and 10 mg lyophilized vials.
Q9: How much bacteriostatic water should be added to Ipamorelin?
Common starting volumes are 1 mL for 2 mg, 2 mL for 5 mg, and 3 mL for 10 mg. Other volumes can be used if concentration math is adjusted accordingly.
Q10: What is the maximum dose of Ipamorelin studied?
In Gobburu et al. 1999, human PK dose-escalation included very high IV exposures (reported up to 140.45 nmol/kg). In Phase II postoperative ileus protocols, dosing reached 0.03 mg/kg IV twice daily for up to 7 days. Community GH-focused protocols typically cap routine single SubQ injections near 300 mcg due to practical plateau behavior.
Q11: How should reconstituted Ipamorelin be stored?
Store reconstituted ipamorelin at 2-8C protected from light and use within about 28 days. Avoid repeated freeze-thaw cycles for mixed solution.
Q12: What clinical trials have been conducted on Ipamorelin?
Key human data include the Gobburu et al. PK/PD study and Phase II postoperative ileus trials such as NCT00672074 and NCT01280344. No clinical trials have established efficacy for GH optimization endpoints.
Sources & Research
- Raun K, Hansen BS, Johansen NL, et al. "Ipamorelin, the first selective growth hormone secretagogue." European Journal of Endocrinology, 1998 PubMed DOI: 10.1530/eje.0.1390552.
- Gobburu JV, Agerso H, Jusko WJ, Ynddal L. "Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers." Pharmaceutical Research, 1999 PubMed.
- Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. "Prospective, randomized, controlled, proof-of-concept study of the Ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients." International Journal of Colorectal Disease, 2014 PubMed DOI: 10.1007/s00384-014-2030-8.
- Ishida J, Saitoh M, Ebner N, et al. "Growth hormone secretagogues: history, mechanism of action, and clinical development." JCSM Rapid Communications, 2020 DOI: 10.1002/rco2.9.
- Hansen BS, Raun K, Nielsen KK, et al. "Pharmacological characterisation of a new oral GH secretagogue, NN703." European Journal of Endocrinology, 1999 PubMed.
- ClinicalTrials.gov - Safety and Efficacy of Ipamorelin Compared to Placebo for the Recovery of Gastrointestinal Function (NCT01280344). Trial.
- ClinicalTrials.gov - Ipamorelin in Postoperative Ileus (NCT00672074). Trial.
- FDA Summary Report: Ipamorelin Acetate. PDF.
- Buscail E, Deraison C. "Postoperative ileus: A pharmacological perspective." British Journal of Pharmacology, 2022 DOI: 10.1111/bph.15800.
- Wikipedia - Ipamorelin. Link.
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The information on this page is for educational and research reference purposes only. Ipamorelin is an experimental compound and is not FDA-approved for any indication. No compounds discussed on this site are intended for human consumption. This is not medical advice.
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