Ipamorelin
Growth Hormone / IGF-1 AxisPreclinicalAlso known as: Ipam, IPA
Ipamorelin is a selective pentapeptide ghrelin receptor (GHS-R1a) agonist — one of the most studied growth hormone secretagogues (GHS) in the biohacking community and the modern companion to CJC-1295 / MOD-GRF 1-29. Its five-amino-acid sequence (Aib-His-D-2Nal-D-Phe-Lys-NH₂) was discovered by Novo Nordisk and published in 1998 as "the first selective growth hormone secretagogue" (Raun et al., 1998). The word "selective" is the critical term.
Reconstitution Calculator for Ipamorelin
Pre-filled · 5mg vial · 200mcg dose
Overview
At A Glance
Ipamorelin acts as a selective agonist at the growth hormone secretagogue receptor 1a (GHS-R1a), the same receptor activated by endogenous ghrelin — the "hunger hormone" secreted primarily by P/D1 cells in the gastric fundus. The distinguishing feature of ipamorelin among GHS pep…
Mechanism of Action
Ipamorelin acts as a selective agonist at the growth hormone secretagogue receptor 1a (GHS-R1a), the same receptor activated by endogenous ghrelin — the "hunger hormone" secreted primarily by P/D1 cells in the gastric fundus. The distinguishing feature of ipamorelin among GHS peptides is its receptor specificity profile, which explains its clean side-effect profile.
1. GHS-R1a agonism (Gq/11 / PLC / IP₃ / Ca²⁺ pathway)
- GHS-R1a is a Class A G-protein-coupled receptor expressed on pituitary somatotrophs, hypothalamic arcuate-nucleus neurons, and (at lower density) gastric cells, pancreatic islets, and cardiomyocytes
- Ligand binding activates Gq/11, triggering phospholipase-C, which cleaves PIP₂ into IP₃ and DAG
- IP₃ mobilizes intracellular Ca²⁺; DAG activates PKC
- Net effect: depolarization of the somatotroph and rapid exocytosis of preformed GH granules
- GH rise is detectable within 15 minutes and peaks at 30-60 minutes post-injection
Ipamorelin has ~EC₅₀ of 1.3 nM at GHS-R1a — similar to native ghrelin but with a dramatically different selectivity profile at secondary sites (Raun et al., 1998).
2. The "selective" property — why ipamorelin is different from GHRP-2 / GHRP-6 / hexarelin
All GHS peptides activate GHS-R1a, but the earlier generation (hexarelin, GHRP-6) also cross-reacted with adjacent receptors on corticotrophs and lactotrophs, producing:
- Cortisol elevation (via ACTH release)
- Prolactin elevation
- ACTH elevation
Ipamorelin, at doses up to 30x the GH-releasing ED₅₀, produces no significant elevation of cortisol, prolactin, ACTH, LH, FSH, or TSH (Johansen et al., 1999; Svensson et al., 2000). This selectivity is the primary clinical reason it became the GHS peptide of choice for long-term biohacking protocols — the absence of cortisol elevation means it can be stacked without compromising recovery, immune function, or sleep architecture.
3. Synergy with GHRH analogs (the foundation of the GHS stack)
The standard biohacking protocol pairs ipamorelin with a GHRH analog (most commonly MOD-GRF 1-29 / CJC-1295 without DAC) because the two signaling pathways converge on the same pituitary cell through different second messengers:
| Pathway | Receptor | G-protein | Second Messenger | Effect on Somatotroph |
|---|---|---|---|---|
| Ipamorelin | GHS-R1a | Gq/11 | IP₃ / Ca²⁺ / DAG-PKC | Depolarization + exocytosis |
| MOD-GRF 1-29 | GHRHR | Gs | cAMP / PKA / CREB | Gene transcription + granule mobilization |
Dual activation produces a GH pulse 3-5x larger than either agent alone and recruits a larger fraction of the total somatotroph reserve (Bowers et al., 1991). This is why GHRH-only or ghrelin-only protocols are suboptimal and nearly all clinical and research protocols use the combination.
4. Pulsatile release preserves physiology
Because ipamorelin clears in ~2 hours, each injection produces a discrete GH pulse that is reabsorbed into the body's normal pulsatile GH architecture. Between pulses, somatostatin (GHIH) can appropriately suppress GH — preserving negative feedback and preventing the receptor desensitization seen with sustained-release analogs like CJC-1295 with DAC.
5. Downstream effects: IGF-1, body composition, sleep
- Acute GH pulse → hepatic IGF-1 synthesis (peaks at ~24h post-dose)
- IGF-1 drives muscle protein synthesis, cartilage deposition, and lipolysis in adipose tissue
- Consistent dosing elevates steady-state IGF-1 by ~30-80% over baseline within 2-4 weeks (Sigalos & Pastuszak, 2018)
- Secondary effects: improved slow-wave sleep (GH pulses physiologically occur during SWS), accelerated wound/connective tissue repair, modest lean-mass gains in hypogonadal populations
6. Secondary physiologic effects (ghrelin-receptor biology)
Because GHS-R1a is expressed beyond the pituitary, chronic ipamorelin administration has minor effects on:
- Appetite — generally mild increase (much less than native ghrelin due to the shorter duration of action)
- Gastric motility — accelerates gastric emptying; this is why it was developed for post-operative ileus
- Cardiovascular — cardioprotective and anti-inflammatory signaling in some animal models (Muccioli et al., 2002)
Overview
Ipamorelin is a selective pentapeptide ghrelin receptor (GHS-R1a) agonist — one of the most studied growth hormone secretagogues (GHS) in the biohacking community and the modern companion to CJC-1295 / MOD-GRF 1-29. Its five-amino-acid sequence (Aib-His-D-2Nal-D-Phe-Lys-NH₂) was discovered by Novo Nordisk and published in 1998 as "the first selective growth hormone secretagogue" (Raun et al., 1998).
The word "selective" is the critical term. Earlier GHS peptides (hexarelin, GHRP-6, GHRP-2) all release GH but also raise cortisol, prolactin, and ACTH — because the ghrelin receptor is expressed on corticotrophs and lactotrophs as well as somatotrophs. Ipamorelin is the first and only GHS peptide clinically characterized as producing no significant rise in cortisol, prolactin, ACTH, LH, FSH, or TSH even at doses 30-fold above the GH-releasing dose (Johansen et al., 1999). This makes it functionally clean — you get the anabolic GH/IGF-1 axis activation without the stress-hormone and mammary-tissue side effects that plague GHRP-2 and GHRP-6.
Ipamorelin has an in vivo half-life of approximately 2 hours in humans (Gobburu et al., 1999). Each subcutaneous injection produces a single transient GH pulse peaking at 30-60 minutes. Typical dosing is 100-300 mcg SC, 1-3 times daily, almost always co-administered with a GHRH analog (MOD-GRF 1-29 or sermorelin) to exploit the well-documented ghrelin × GHRH synergy — the two pathways converge on pituitary somatotrophs through distinct second messengers and produce a GH pulse 3-5x greater than either agent alone (Bowers et al., 1991).
Clinical development by Helsinn Therapeutics (licensed from Novo Nordisk) reached Phase 2B for post-operative ileus, where IV ipamorelin demonstrated faster recovery of gastrointestinal transit after abdominal surgery (Beck et al., 2013). Development for that indication was subsequently halted, and ipamorelin is not FDA-approved for any indication. It remains widely available as a compounding-pharmacy peptide and research-use reagent.
See our Ipamorelin Dosage Guide and Reconstitution Tool for protocol specifics. The standard stack partner is documented at /compound/cjc-1295.
Potential Research Fields
Chemical Information
IUPAC Name
Aib-His-D-2-Nal-D-Phe-Lys-NH2
CAS Number
170851-70-4
Molecular Formula
C38H49N9O5
Molecular Mass
711.86 g/mol
Dosing & Protocols
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Interactions
Interaction Matrix
Contraindications
Absolute contraindications
- Active malignancy — GH and IGF-1 are trophic factors for multiple cancer cell lines. While ipamorelin-specific cancer data does not exist, the GH/IGF-1 axis is implicated in colorectal, prostate, breast, and hepatocellular cancer progression (Renehan et al., 2004). Do not use during active cancer treatment or within 5 years of complete remission without oncologist clearance
- Known or suspected pituitary tumor / acromegaly — superimposing exogenous secretagogue on an already-hyperactive somatotroph axis can accelerate tumor growth and precipitate acromegalic complications
- Active diabetic retinopathy — GH elevation can worsen proliferative retinopathy; absolute contraindication until retinopathy is stabilized
- Pregnancy or breastfeeding — no safety data; do not use
- Age <18 — no pediatric safety data; pediatric GHD is managed with prescription GHRH analogs (sermorelin) under endocrinology supervision, not biohacking protocols
Relative contraindications (consult physician before use)
- Type 2 diabetes or pre-diabetes — GH elevation impairs insulin sensitivity; use requires careful glucose monitoring and may accelerate progression in borderline cases
- Uncontrolled hypertension — fluid retention can exacerbate blood pressure
- History of carpal tunnel syndrome — fluid retention and connective tissue expansion can worsen symptoms
- Hypothyroidism — thyroid status affects GH axis; optimize thyroid first
- History of pituitary or hypothalamic surgery or radiation — altered GHRH/ghrelin receptor status; unpredictable response
Drug interactions
- Insulin and oral hypoglycemics — ipamorelin's effect on glucose tolerance may require dose adjustments of antidiabetic medications
- Corticosteroids — chronic systemic corticosteroids suppress the GH axis and blunt ipamorelin response
- Recombinant GH (Somatropin) — redundant; do not combine
- Other GHS peptides — do not stack (see stacking notes)
Monitoring requirements for users
- Baseline labs: Fasting glucose, HbA1c, IGF-1, complete metabolic panel, CBC, PSA (men >40), full thyroid panel
- 4-6 weeks into dosing: Fasting glucose, IGF-1 (confirm within age-appropriate range)
- End of each cycle: Full panel; look for HbA1c creep, PSA changes, IGF-1 elevation above age-adjusted ULN
Discontinuation criteria
Stop ipamorelin and consult a clinician if you develop:
- Persistent peripheral edema or facial swelling
- New or worsening carpal tunnel symptoms
- IGF-1 levels >300 ng/mL (supraphysiologic in most adults)
- Fasting glucose persistently >110 mg/dL or HbA1c rising >0.4 points
- Any new palpable mass, changing mole, or unexplained weight loss (cancer workup indicated)
- Severe headache, visual changes (rule out pituitary pathology)
Research Disclaimer
This interaction data is compiled from published research and community reports. It may not be exhaustive. Always consult a healthcare professional before combining compounds.
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| Vendor | Product | Form | Qty | Price | $/mg | Coupon | |
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Ipamorelin 5mg | vial | 1 vial● Out of Stock | $35.00BEST | $7.000 | — | Sign in for stock alert |
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Ipamorelin 10mg | vial | 1 vial● In Stock | $42.00VALUE | $4.200 | — | |
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Price History
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Related Compounds
View AllCJC-1295 (Mod GRF 1-29)
Growth Hormone / IGF-1 AxisPreclinicalCJC-1295 without DAC (also called Modified GRF 1-29 or MOD-GRF 1-29) is a 30-amino-acid analog of the first 29 residues of endogenous Growth Hormone Releasing Hormone (GHRH), with four strategic substitutions (D-Ala² for DPP-4 resistance, Gln⁸, Ala¹⁵, Leu²⁷) that extend its plasma half-life from <2 minutes (native GHRH) to ~30 minutes.
CJC-1295 with DAC
Growth Hormone / IGF-1 AxisPhase 2CJC-1295 with DAC (Drug Affinity Complex) is a modified form of CJC-1295 that incorporates a maleimidopropionic acid (MPA) reactive group at the C-terminus.
GHRP-2
Growth Hormone / IGF-1 AxisPhase 2GHRP-2 (growth hormone-releasing peptide-2), also known as pralmorelin and KP-102, is a synthetic hexapeptide growth hormone secretagogue that was among the first GHRPs developed in the seminal research of Cyril Bowers and colleagues at Tulane University in the late 1980s and early 1990s.
GHRP-6
Growth Hormone / IGF-1 AxisPhase 2GHRP-6 (growth hormone-releasing peptide-6) is a synthetic hexapeptide with the sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 that binds the ghrelin receptor (GHS-R1a) to stimulate endogenous growth hormone release.
Hexarelin
Growth Hormone / IGF-1 AxisPhase 2Hexarelin (also called examorelin) is a potent synthetic hexapeptide growth hormone secretagogue with the sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2.
IGF-1 LR3
Growth Hormone / IGF-1 AxisPhase 2IGF-1 LR3 (Long R3 IGF-1) is a synthetic analog of human insulin-like growth factor 1 modified at two positions to dramatically extend its serum half-life and amplify its tissue bioactivity compared to native IGF-1.
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4/21/2026Research Score
11 PubMed studies
Quality Indicators
Data Completeness
100%Research Credibility
Quick Facts
Half-Life
~2 hours (plasma)
Molecular Weight
711.86 g/mol
Administration
subcutaneous, intravenous (clinical only)
CAS Number
170851-70-4
Trial Phase
Preclinical
Safety Profile
Common Side Effects
- • Transient head rush or flushing immediately post-injection
- • Mild injection site irritation
- • Transient hunger increase (ghrelin pathway activation)
- • Water retention during initial 1-2 weeks of use
- • Mild tingling or numbness in extremities (transient)
Research Disclaimer
This information is for educational and research purposes only. Not intended as medical advice. Consult a healthcare professional before use.
Frequently Asked Questions
What makes ipamorelin different from other GHS peptides like GHRP-2 or GHRP-6?
Ipamorelin is the first and only GHS peptide that releases growth hormone without elevating cortisol, prolactin, ACTH, LH, FSH, or TSH — even at doses 30x the GH-releasing dose (Johansen et al., 1999). Earlier GHS peptides (GHRP-2, GHRP-6, hexarelin) all cross-activate corticotrophs and lactotrophs, producing cortisol and prolactin spikes that compromise recovery, immune function, and (for men) breast tissue. This 'selective' property is the reason ipamorelin became the default GHS peptide for modern biohacking protocols.
Do I need to stack ipamorelin with CJC-1295 or MOD-GRF 1-29?
Functionally, yes. Ipamorelin alone produces a modest GH pulse. Paired with a GHRH analog (MOD-GRF 1-29 / CJC-1295 without DAC), the GH pulse is 3-5x larger — because the two signaling pathways converge on the same pituitary somatotroph through distinct second messengers (Gq/PLC/IP₃ vs Gs/cAMP/PKA) and activate a much larger fraction of the GH reserve. Nearly all clinical and research protocols use the combination; standalone ipamorelin is primarily used in weeks 1-4 of a beginner protocol to confirm tolerance before adding the GHRH partner.
What's the correct ipamorelin dose and how often should I inject?
Therapeutic range is 100-300 mcg subcutaneously per injection, 1-3x daily. Common protocols: (1) Sleep / recovery focus — 200 mcg pre-bed once daily; (2) Body composition — 200 mcg + 100 mcg MOD-GRF 1-29 twice daily (pre-bed + morning fasted); (3) Advanced — 100-200 mcg tri-daily. Dose-response plateaus above 300 mcg per injection — more frequent smaller pulses outperform larger single doses. All doses must be in a fasted state (≥2 hours post-meal); elevated insulin blunts GH response by 50-70%.
Why must I inject ipamorelin in a fasted state?
Elevated insulin suppresses pituitary GH release through increased somatostatin tone and reduced somatotroph sensitivity. Post-meal dosing can cut the GH pulse by 50-70%. The two reliably fasted windows are pre-bed (2+ hours after the evening meal) and morning on waking (before the first meal). Carbohydrates and protein both elevate insulin — fat alone has minimal effect but a pure fasted window is cleanest. Alcohol independently suppresses GH; avoid within 4 hours of dosing.
How long does it take to see results from ipamorelin?
Effects appear on different timelines: (1) Sleep quality and deeper SWS within 1-3 nights; (2) Recovery between training sessions within 1-2 weeks; (3) IGF-1 elevation measurable at 4 weeks (typically +30-80% over baseline with the ipamorelin + MOD-GRF stack); (4) Body composition changes (lean mass ↑, visceral fat ↓) visible at 8-12 weeks with consistent dosing; (5) Connective tissue / injury repair acceleration within 4-6 weeks, often used alongside BPC-157 and TB-500. Note that effects are dose-dependent — 200 mcg once daily will produce subtler changes than the 2-3x daily stacked protocol.
What are the actual side effects of ipamorelin?
The cleanest profile of any GHS peptide. Common: injection site reactions, transient hunger (less than GHRP-6), vivid dreams, brief head-heaviness 10-30 min post-injection. Uncommon: mild water retention, hand paresthesias (early water-retention sign), joint stiffness as IGF-1 rises. Rare: insulin resistance at high chronic doses, carpal tunnel symptoms. Unlike GHRP-2/6, ipamorelin does NOT elevate cortisol, prolactin, or ACTH. Most side effects are dose-dependent — stay at or below 300 mcg per injection and cycle (8-12 weeks on / 4-6 weeks off) to minimize cumulative burden.
Is ipamorelin safer than injecting actual growth hormone (somatropin)?
Mechanistically, yes — but with caveats. Ipamorelin amplifies the body's own pulsatile GH release via the pituitary, preserving negative feedback (somatostatin can still suppress GH between pulses) and physiologic pulse architecture. Exogenous somatropin bypasses the pituitary and produces tonic, non-pulsatile GH elevation, which carries a higher burden of insulin resistance, edema, and theoretical cancer-axis concerns. However, both share the GH/IGF-1 safety envelope: active malignancy, diabetic retinopathy, and pituitary tumors are absolute contraindications for both. Ipamorelin is NOT FDA-approved; somatropin is FDA-approved for specific indications. Neither is a replacement for the other — they occupy different therapeutic niches.
Does ipamorelin affect appetite or cause weight gain?
Mildly. Ipamorelin activates the same receptor (GHS-R1a) as ghrelin, which is involved in hunger signaling. In practice the appetite effect is much smaller than GHRP-6 because ipamorelin's ~2-hour half-life limits tonic activation of hypothalamic feeding neurons. Most users report minor evening hunger at the pre-bed dose — this can be managed by injecting 20-30 min before lights-out so sleep supersedes the appetite signal. Weight typically goes UP on ipamorelin due to (a) increased lean body mass from GH/IGF-1 elevation and (b) modest fluid retention; fat mass typically goes DOWN. Tracking body composition (DEXA or bioimpedance) is more useful than scale weight.
Can I combine ipamorelin with semaglutide, TRT, BPC-157, or other peptides?
Yes, with different rationales. Semaglutide / tirzepatide: ipamorelin + MOD-GRF 1-29 preserves lean mass during the GLP-1-induced caloric deficit; this is a common recomposition stack. TRT: fully complementary — HPG and GH axes are independent; combined use is standard in integrative clinics. BPC-157 / TB-500: synergistic for connective tissue repair — GH/IGF-1 provides the systemic anabolic signal that BPC-157 local repair mechanisms can leverage. NAD+ / NMN: mitochondrial support for the increased protein synthesis demand. DO NOT stack with other ghrelin-receptor agonists (GHRP-2/6, hexarelin, MK-677) — redundant at the receptor — or with exogenous recombinant GH (mechanistically defeating).
Is ipamorelin legal and where does it come from?
Ipamorelin is not FDA-approved for any indication in the United States. Clinical development by Helsinn Therapeutics (licensed from Novo Nordisk) for post-operative ileus reached Phase 2B and was halted despite positive efficacy data (Beck et al., 2013). It is legal to purchase as a research chemical (not for human use) and is widely available through compounding pharmacies on a prescription basis from integrative medicine and anti-aging clinics. Legal status for personal use varies by jurisdiction — always verify local regulations. Quality varies substantially between suppliers; third-party HPLC and mass spec testing is the only way to verify identity and purity. See our Best Peptide Vendors 2026 guide for vetted sources.
Research Tools
Related Compounds
View AllCJC-1295 (Mod GRF 1-29)
Growth Hormone / IGF-1 AxisPreclinicalCJC-1295 without DAC (also called Modified GRF 1-29 or MOD-GRF 1-29) is a 30-amino-acid analog of the first 29 residues of endogenous Growth Hormone Releasing Hormone (GHRH), with four strategic substitutions (D-Ala² for DPP-4 resistance, Gln⁸, Ala¹⁵, Leu²⁷) that extend its plasma half-life from <2 minutes (native GHRH) to ~30 minutes.
CJC-1295 with DAC
Growth Hormone / IGF-1 AxisPhase 2CJC-1295 with DAC (Drug Affinity Complex) is a modified form of CJC-1295 that incorporates a maleimidopropionic acid (MPA) reactive group at the C-terminus.
GHRP-2
Growth Hormone / IGF-1 AxisPhase 2GHRP-2 (growth hormone-releasing peptide-2), also known as pralmorelin and KP-102, is a synthetic hexapeptide growth hormone secretagogue that was among the first GHRPs developed in the seminal research of Cyril Bowers and colleagues at Tulane University in the late 1980s and early 1990s.
GHRP-6
Growth Hormone / IGF-1 AxisPhase 2GHRP-6 (growth hormone-releasing peptide-6) is a synthetic hexapeptide with the sequence His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 that binds the ghrelin receptor (GHS-R1a) to stimulate endogenous growth hormone release.
Hexarelin
Growth Hormone / IGF-1 AxisPhase 2Hexarelin (also called examorelin) is a potent synthetic hexapeptide growth hormone secretagogue with the sequence His-D-2-methyl-Trp-Ala-Trp-D-Phe-Lys-NH2.
IGF-1 LR3
Growth Hormone / IGF-1 AxisPhase 2IGF-1 LR3 (Long R3 IGF-1) is a synthetic analog of human insulin-like growth factor 1 modified at two positions to dramatically extend its serum half-life and amplify its tissue bioactivity compared to native IGF-1.
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