Ipamorelin Phase II Complete

What It Is

Ipamorelin is a synthetic pentapeptide (Aib-His-D-2-Nal-D-Phe-Lys-NH₂) that selectively activates the ghrelin / growth hormone secretagogue receptor (GHS-R1a), driving pulsatile growth hormone (GH) release from the pituitary. It was identified and characterized at Novo Nordisk's GH Biology department under development code NNC 26-0161 and first described by Raun and colleagues in a landmark 1998 paper in the European Journal of Endocrinology. The structural design started from GHRP-1 and removed the central Ala-Trp dipeptide; the resulting pentapeptide retained potent GH-releasing activity but, critically, lost the off-target hypothalamic-pituitary-adrenal (HPA) activation that plagued earlier GHRPs.

The compound's defining feature is selectivity. In pig studies and subsequent human data, ipamorelin releases GH with potency comparable to GHRP-6 and similar efficacy, but — unlike GHRP-6, GHRP-2, or hexarelin — does not raise plasma ACTH, cortisol, prolactin, FSH, LH, or TSH, even at doses >200× the ED50 for GH release. Raun's concluding sentence, now three decades old, still describes the compound's market position: "ipamorelin is the first GHRP-receptor agonist with a selectivity for GH release similar to that displayed by GHRH." That phrase is why the peptide-therapy community has used ipamorelin for almost every stacked GHRH-plus-GHS protocol since the mid-2000s.

Clinical development was pursued by Novo Nordisk, then licensed to Helsinn Therapeutics for postoperative ileus. A Phase 2 proof-of-concept trial (Beck, Sweeney, McCarter; Ipamorelin 201 Study Group, 2014) enrolled 114 bowel-resection patients randomized to ipamorelin 0.03 mg/kg IV twice daily for up to 7 days vs placebo. The compound was well tolerated, but the primary efficacy endpoint missed statistical significance (median time to first tolerated meal 25.3 vs 32.6 hours, p = 0.15). Subsequent Phase 3 development was discontinued. Ipamorelin was never submitted for FDA approval and today exists almost entirely as a research chemical and peptide-clinic compound.

Mechanism of Action

Ipamorelin is a selective agonist of the ghrelin receptor (GHS-R1a), a Gq-coupled GPCR expressed densely in the hypothalamic arcuate nucleus and anterior pituitary somatotropes. Its signaling is the same as endogenous ghrelin at this receptor but without ghrelin's other central and peripheral effects.

• GHS-R1a agonism (pituitary somatotrope) — Binding activates phospholipase C, mobilizes intracellular calcium, and drives GH exocytosis from somatotropes. The pulse is rapid, dose-dependent, and mirrors the kinetics of endogenous ghrelin-induced GH release. Raun (1998) reported an in vivo ED50 of 2.3 ± 0.03 nmol/kg in conscious swine with a peak plasma GH ~65 ng/mL.
• Central synergy with GHRH — Ghrelin-receptor activation and GHRH-receptor activation are physiologically complementary: GHRH opens the somatotrope to release, and ghrelin-class stimulation amplifies pulse amplitude. When combined (e.g., ipamorelin + Modified GRF (1-29) or ipamorelin + CJC-1295 DAC), GH release is markedly greater than either compound alone — a pharmacologic synergy shown in rat and human work with GHRP + GHRH co-administration.
• Somatostatin-sensitive — Like all GHRPs, ipamorelin does not override hypothalamic somatostatin tone. GH release is gated by somatostatin; this is why timing (fasting, pre-sleep) matters practically and why ipamorelin does not produce supraphysiologic GH levels sustained beyond the pulse window.
• Selectivity (what ipamorelin does NOT do) — Raun's selectivity work is the mechanistic foundation of ipamorelin's entire clinical identity. In swine at 200× the ED50, ipamorelin did not elevate ACTH or cortisol, did not affect prolactin, did not change FSH, LH, or TSH. This contrasts with GHRP-6 and GHRP-2 (which raise ACTH and cortisol acutely) and with MK-677 / ibutamoren (which raises prolactin and can modestly raise cortisol).
• Pulsatile, not tonic — Plasma half-life is ~2 hours, and the GH pulse duration is ~1–3 hours after a standard dose. Ipamorelin is therefore used as the "pulse generator" in stacked protocols, dosed 1–3× daily to mimic native episodic GH secretion rather than to create a tonic plateau.
• Bone-formation effect (preclinical) — Svensson et al. (2000) showed that 12-week continuous SC infusion of ipamorelin (0.5 mg/kg/day) in adult female rats increased total-body and regional bone mineral content (BMC) as measured by DXA, with increased ash weight and increased femoral/vertebral volume. This is consistent with the broader class-effect of GH/IGF-1 elevation on bone remodeling and is one of the mechanistic bases for using ipamorelin in osteopenia or periosteal-repair contexts — though no human bone data exist.
• GI motility (the ileus hypothesis) — Ghrelin-receptor stimulation is pro-kinetic in the upper and lower gastrointestinal tract. Greenwood-Van Meerveld et al. demonstrated ipamorelin's efficacy in a rodent model of postoperative ileus, supporting the Helsinn Phase 2 trial. The human trial showed a non-significant trend toward earlier return of GI function but missed the primary endpoint — which is why the development program stopped.

What the Research Shows

Ipamorelin's published evidence base is small but internally consistent: preclinical work establishes potent, selective GH release and a favorable side-effect profile; Phase 1 human PK/PD work confirms the GH response; Phase 2 in postoperative ileus was negative on the primary endpoint.

• Discovery and preclinical potency (Raun 1998) — Ipamorelin released GH from primary rat pituitary cells with EC50 = 1.3 ± 0.4 nmol/L and Emax = 85 ± 5% of GHRP-6. In conscious swine, ED50 = 2.3 ± 0.03 nmol/kg, Emax 65 ± 0.2 ng GH/mL. GHRP-2 had higher potency (ED50 = 0.6 nmol/kg) but lower efficacy, and both GHRP-2 and GHRP-6 elevated ACTH and cortisol. Ipamorelin did not (Eur J Endocrinol 139:552-561).
• Phase 1 human PK/PD (Gobburu 1999) — Five ascending intravenous infusion rates (4.21, 14.02, 42.13, 84.27, 140.45 nmol/kg over 15 minutes), 8 healthy male subjects per dose. Linear pharmacokinetics, two-compartment PK model, dose-dependent GH pulse with peak GH at ~15–20 minutes post-infusion. Plasma ipamorelin persisted beyond the GH pulse and drove progressively smaller secondary pulses. No ACTH or cortisol change (Pharm Res 16:1412-1416).
• Phase 1 multiple-ascending dose (Rasmussen 1998, abstract) — Randomized, double-blind, placebo-controlled, parallel-group, dose-escalation study in healthy subjects. Repeat dosing up to 7 days was well-tolerated; adverse event rates were comparable to placebo; sustained GH secretion response without desensitization over the dosing window (Growth Horm IGF Res 8:332, abstract).
• Preclinical bone formation (Svensson 2000) — 12-week continuous ipamorelin (0.5 mg/kg/day via osmotic minipump) in adult female Sprague-Dawley rats increased total-body BMC, tibia BMC, and vertebral (L3-L6) BMC relative to vehicle control. Effect comparable in magnitude to GHRP-6 at equivalent dose; both less than the rhGH positive control but without the rhGH confounders. Femur and vertebral volumes were also increased (J Endocrinol 165:569-577).
• Preclinical ileus (Greenwood-Van Meerveld et al.) — Rodent postoperative ileus model showed improved gastric dysmotility with ipamorelin. Motivated the Helsinn Phase 2.
• Phase 2 postoperative ileus (Beck et al. 2014) — Randomized, placebo-controlled, multicenter proof-of-concept trial. 114 patients undergoing bowel resection, ipamorelin 0.03 mg/kg IV BID up to 7 days. Safety population: AE rate 87.5% (ipamorelin) vs 94.8% (placebo). Efficacy: median time to first tolerated meal 25.3 h vs 32.6 h (p = 0.15); time to first bowel movement numerically shorter but not significant. The compound was well tolerated but did not reach efficacy threshold; subsequent development terminated (Int J Colorectal Dis 29:1527-1534).
• Community and wellness-clinic "evidence" — Substantial practitioner reporting on ipamorelin + CJC-1295 or ipamorelin + Modified GRF (1-29) protocols for body composition, sleep quality, recovery, and aesthetic endpoints. These are uncontrolled, selection-biased, and should not be treated as evidence for efficacy on these endpoints. They are, at best, a description of how the peptide is being used.

Human Data

Consolidating the human evidence:

• Phase 1 PK/PD — Gobburu et al. 1999 (IV ascending dose, N = 40, healthy men) and Rasmussen et al. 1998 (single-dose + MAD, healthy subjects). Confirmed dose-dependent GH release, linear PK, ~2-hour plasma half-life, no ACTH/cortisol elevation, excellent short-term tolerability.
• Phase 2 postoperative ileus — Beck et al. 2014 (ClinicalTrials.gov NCT00672074). Helsinn-sponsored multicenter trial. N = 114 (modified intent-to-treat). Primary endpoint (time to first tolerated meal) missed statistical significance. Safety signal favorable.
• No obesity / body-composition / anti-aging RCTs — Despite widespread off-label use, ipamorelin has never been evaluated in a randomized, controlled trial for body composition, fat loss, lean-mass preservation, sleep, or "anti-aging" endpoints.
• No long-term safety data — The longest published human exposure is the 7-day Helsinn trial. Chronic multi-month use (common in wellness-clinic practice) has no published safety data.

Dosing from the Literature

The Phase 1 and Phase 2 trials used IV dosing; community use is almost entirely subcutaneous. The following synthesizes Phase 1 pharmacology with published practitioner protocols.

Reconstitution & Storage

Ipamorelin is supplied as a lyophilized (freeze-dried) powder, most commonly in 2 mg or 5 mg vials. Reconstitution and storage follow standard peptide protocol.

• Reconstitution — Inject bacteriostatic water slowly down the inside wall of the vial at a 45° angle. Swirl gently — never shake. The solution should be clear and colorless.
• Storage — Lyophilized powder is stable at room temperature short-term and should be refrigerated for long-term storage (manufacturer COAs typically indicate 2 years at –20°C or 2 years refrigerated). After reconstitution, refrigerate at 2–8°C and use within 28–30 days. Do not freeze reconstituted solution.
• Co-injection with GHRH analogs — Ipamorelin and Modified GRF (1-29) or CJC-1295 can be drawn into the same insulin syringe and injected together. The two peptides are compatible for same-session administration. Do not pre-mix and store combined.
• Inspection — Discard if solution shows cloudiness, particles, color change, or unusual odor. Ipamorelin is relatively stable and tolerates light handling, but any visible change is a discard signal.
• Injection technique — 29G–31G half-inch insulin syringe, SubQ at the abdomen (rotate sites), thigh, or tricep. Clean the stopper and skin with alcohol, pinch the skin, insert at 45°, inject slowly, apply gentle pressure after withdrawal.

→ Use the Kalios Dosing Calculator for exact syringe units

Side Effects & Risks

Ipamorelin's safety signal in formal trials has been favorable, and its selectivity for GH over ACTH/cortisol/prolactin/aldosterone underpins that reputation. Risks listed below include documented, theoretical, and chronic-use extrapolations.

• Injection-site reactions — Mild erythema, pruritus, occasional bruising. Typically self-limited. The most common reported AE.
• Transient flushing, headache, mild dizziness — Reported in Phase 1 at higher doses, usually post-injection and self-resolving within minutes.
• Hunger / transient appetite increase — Less pronounced than MK-677 or GHRP-6, but some ipamorelin users report mild appetite stimulation in the 30–60 minutes post-injection (ghrelin-receptor physiology). Often disappears with chronic dosing.
• Sleep architecture — Users frequently report more vivid dreams and subjectively deeper sleep with pre-bed dosing. Paradoxically, a minority report initial insomnia or sleep disruption. Adjust timing if sleep quality worsens.
• No meaningful cortisol / ACTH / prolactin elevation — This is the headline selectivity finding. Raun (1998) showed no elevation at >200× the ED50 for GH release; Gobburu (1999) confirmed in humans. This is ipamorelin's core differentiator from GHRP-6 / GHRP-2 / hexarelin.
• Chronic IGF-1 elevation (theoretical) — Sustained use raises circulating IGF-1. Elevated IGF-1 is epidemiologically associated with colorectal, prostate, and breast cancer risk. Whether iatrogenic IGF-1 elevation shifts individual cancer risk is unresolved. Keep IGF-1 within upper-normal range, not above it.
• Insulin sensitivity — Acute GH elevation is counter-regulatory to insulin. Chronic GHS use may worsen fasting glucose or HbA1c, particularly in users with baseline insulin resistance. Monitor fasting glucose/HbA1c at baseline and during chronic use.
• Water retention / peripheral edema — Less frequent than with high-dose rhGH or chronic high-dose CJC-1295 DAC, but possible, especially in combination stacks with sustained IGF-1 elevation.
• Purity / contamination — Gray-market ipamorelin supply varies substantially. Require third-party HPLC/MS Certificates of Analysis showing purity >98%.
• Anti-doping — Ipamorelin is prohibited at all times under WADA Section S2 (Peptide Hormones and Growth Factors) as a growth hormone secretagogue. Athletes subject to testing should not use it.
• Drug interactions — Somatostatin analogs (octreotide, lanreotide) directly antagonize GHS-R1a-driven GH release. Corticosteroids suppress central GH axis. Oral antidiabetics may need adjustment with chronic use.
• No data in pregnancy, breastfeeding, pediatrics — Do not use in these populations.

Supportive Nutrition & Supplements

Ipamorelin is typically one component of a stacked GHRH + GHS protocol. Whether paired with Modified GRF (1-29), CJC-1295 DAC, or tesamorelin, the downstream body-composition and recovery effects depend on adequate substrate: amino acids, sleep, training load, and micronutrient cofactors. The following is general GH-axis support physiology; none of it is ipamorelin-specific research.

• Protein intake — 1.6–2.2 g/kg bodyweight/day, distributed across 3–5 feedings. Leucine-rich protein (whey isolate, eggs, lean meat, cottage cheese) drives mTOR-mediated protein synthesis, which is how elevated GH/IGF-1 actually translates into lean-tissue adaptation. Under-eating protein wastes the signal.
• Sleep hygiene — Ipamorelin's most consistent user-reported benefit is deeper/more vivid sleep. The native nocturnal GH pulse occurs during slow-wave sleep, and pre-bed ipamorelin dosing is designed to amplify that window. The window only exists if sleep is consolidated — consistent bedtime, dark/cool room, no late alcohol, no late heavy meals.
• Fasting window around injection — Free fatty acids and post-prandial insulin both blunt ghrelin-receptor-driven GH release. Community practice: ≥2 hours fasted before injection and ≥30 minutes after. This is the single most commonly cited "protocol error" that explains non-response.
• Zinc — 15–25 mg elemental/day. Cofactor for IGF-1 bioactivity and protein synthesis. Avoid chronic >40 mg (copper depletion risk).
• Magnesium — 300–400 mg glycinate or threonate, evening. Broad cofactor role in ATP, protein synthesis, and sleep quality. Commonly suboptimal.
• Vitamin D (25-OH) — Target serum 40–60 ng/mL. Low vitamin D status is associated with blunted GH axis response in some studies.
• Glycine — 3–5 g/day, often pre-bed. Rate-limiting for collagen synthesis and supports sleep quality in some trials.
• Creatine monohydrate — 3–5 g/day. Among the most evidence-backed lean-mass and training-capacity supplements; stacks well with any IGF-1-elevating protocol.
• Omega-3 fatty acids (EPA/DHA) — 2–3 g combined daily. Supports the insulin-sensitivity and inflammatory background of chronic GH-axis stimulation.
• L-arginine / L-citrulline (optional) — 5–9 g arginine or 3–6 g citrulline pre-bed or pre-workout. Modest independent GH-releasing effect via somatostatin suppression. Evidence for additive benefit on top of ipamorelin stacks is weak; most protocols do not bother.
• Things to avoid — Alcohol close to dosing (blunts nocturnal GH), chronic corticosteroids (suppresses GH axis centrally), late-night high-fat/high-carb meals (blunt the pre-sleep GH release ipamorelin is trying to amplify), and very-low-calorie dieting (reduces the anabolic substrate IGF-1 elevation is supposed to direct).

What to Expect — Timeline

No controlled human trial has mapped the aesthetic / body-composition response curve for ipamorelin. The timeline below synthesizes Phase 1 pharmacodynamics with widely reported community use patterns. It is field folklore with a pharmacologic anchor — not a clinical prognosis.

• Week 1 (starting) — Most users feel the first effect in sleep quality: more vivid dreams, deeper slow-wave sleep on wearable trackers, occasionally mild initial insomnia if dosed too late. Some mild post-injection flushing or dizziness, typically self-limited.
• Week 2–3 — Sleep effects settle into a consistent pattern. Subjective recovery between training sessions may improve. Appetite may shift mildly (ghrelin-receptor component) — usually modest and often fades over 1–2 weeks. No visible body-composition change.
• Week 4–6 — IGF-1 begins to cumulate (especially with a GHRH analog stacked). Users stacking with CJC-1295 DAC hit near-peak cumulative IGF-1 exposure by week 4. Users on Modified GRF (1-29) + ipamorelin see smaller but pulsatile IGF-1 elevation. Joint comfort, skin/hair signals, and subjective workout recovery are the most commonly reported changes in this window. All uncontrolled.
• Week 6–12 — Visible body-composition changes (if any) appear in this window in responsive users. Magnitude: small increase in lean mass (typically 1–3 lb), modest reduction in abdominal fat, improved muscle fullness. Smaller than most users expect. Photos and waist tape are more honest than scale weight.
• Week 12–16 — Common cycle endpoint. Most reported benefit plateaus here. A 4-week minimum off-period is standard community practice; the pharmacologic rationale for this is limited (ipamorelin is short-acting with no tachyphylaxis documented), but the practice is common.
• Post-cycle — Plasma half-life is ~2 hours; ipamorelin effects wash out within a day. If stacked with CJC-1295 DAC, the IGF-1 tail decays over 3–4 weeks due to the GHRH component. Modified GRF (1-29) washes out within hours.
• Non-responders — A substantial fraction of users (community reports suggest 30–50%) describe no perceivable effect. Common causes: product purity issues, inadequate fasting window before injection, insufficient protein/training substrate, dosing too late for sleep effects, unrealistic expectations about magnitude.
• If you feel worse — Persistent peripheral edema, new carpal-tunnel-type tingling, morning joint stiffness, or fasting glucose drift. Stop, reassess dose and stack, consult a clinician. These are usually IGF-1-related and resolve with dose reduction, but any persistent new symptom on an unapproved compound warrants evaluation.

Quick Compare — Ipamorelin vs GHRP-2 vs GHRP-6 vs MK-677

All four compounds are ghrelin-receptor (GHS-R1a) agonists. They differ in potency, selectivity, administration route, and — most importantly — their off-target endocrine effects.

Practical interpretation:

• Selectivity is the headline — Ipamorelin's defining property is that it releases GH without raising ACTH, cortisol, or prolactin. GHRP-2 and GHRP-6 don't; MK-677 partially doesn't. For users prioritizing a clean HPA profile, ipamorelin is the default.
• Oral convenience vs injection — MK-677 is oral once-daily, which is a significant quality-of-life advantage. The trade-off is a worse metabolic side-effect profile (fasting glucose, insulin, prolactin) and stronger appetite effects.
• Appetite effect trade-off — GHRP-6's strong appetite stimulation is either a feature (cachexia, underweight) or a bug (weight-loss protocols). Ipamorelin's mild appetite effect makes it compatible with a GLP-1/tirzepatide stack, where GHRP-6 would undermine the weight-loss mechanism.
• Dose frequency — Ipamorelin + GHRP-2 / GHRP-6 all require 2–3× daily injections. MK-677 is once-daily. CJC-1295 DAC is once-weekly when stacked.
• Stack partner for GHRH — Ipamorelin is the standard GHS partner for Modified GRF (1-29), CJC-1295, and tesamorelin because its selectivity profile does not muddy the GHRH signal with HPA activation.

→ See full MK-677 profile  •  → See full GHRP-2 profile  •  → See full GHRP-6 profile

Bloodwork & Monitoring

No formal monitoring guidelines exist. The following is a reasonable baseline for anyone using ipamorelin (monotherapy or in a stack) under clinical supervision:

• Baseline IGF-1 — Primary pharmacodynamic marker. Dose to keep IGF-1 in the upper quartile of age-adjusted normal, not above it.
• IGF-1 at 6 and 12 weeks — Track response. Ipamorelin monotherapy produces a modest IGF-1 rise; stacked with GHRH analog produces a larger rise.
• Fasting glucose + HbA1c — Baseline and at 3 months. Catch insulin-resistance drift early.
• Comprehensive metabolic panel (CMP) — Liver and renal function, electrolytes. Baseline and at 3–6 months.
• CBC + lipid panel — Routine. Lipid profile may improve mildly with sustained GH-axis activation.
• Morning cortisol / ACTH (selective) — Ipamorelin does not meaningfully affect these in trials, but testing baseline is reasonable in users with adrenal-axis concerns.
• Prolactin (selective) — Not affected by ipamorelin per Raun's original work; relevant mostly if combining with MK-677 (which can raise prolactin).
• Thyroid panel (TSH + free T4) — GH-axis activation can unmask central hypothyroidism. Recheck if symptomatic.
• Sleep tracking — Subjective or wearable tracking during ipamorelin use is useful given its common indication for "sleep quality" improvement. Baseline vs 4-week comparison helps attribute effect honestly.
• Cancer screening — Age-appropriate. Reasonable risk-management for any chronic GH/IGF-1-elevating protocol.

Practical User Notes

• Timing — Pre-bed (30–60 minutes before sleep) leverages the native nocturnal GH pulse window and is the single most consistent community-reported timing slot. A second dose pre-workout or in the morning is common in multi-dose protocols.
• Fasting window — Food — especially meals containing meaningful fat or carbohydrate — blunts GH release from GHS stimulation via post-prandial insulin and elevated free fatty acids. Community baseline is ≥2 hours fasted before injection and ≥30 minutes fasted after.
• Stacking with a GHRH analog — Ipamorelin is almost always combined with either Modified GRF (1-29) (short-acting, 2–3× daily pulse protocol) or CJC-1295 DAC (long-acting, weekly sustained-tone protocol). Monotherapy ipamorelin produces a smaller GH response than either stack.
• Why not just use MK-677? — MK-677 (ibutamoren) is an oral non-peptide ghrelin-R1a agonist, which is more convenient. It also raises cortisol, prolactin, fasting glucose, and appetite more meaningfully than ipamorelin. Users prioritizing clean selectivity prefer injected ipamorelin; users prioritizing convenience prefer oral MK-677. Different trade-offs.
• Dose response flattens — Community experience is that ipamorelin dose-response flattens around 200–300 mcg per injection. Going above 500 mcg per dose is uncommon and not mechanistically well-justified.
• Sourcing — Require third-party Certificates of Analysis from independent labs. Ipamorelin is relatively simple to synthesize cleanly; COAs should show >98% HPLC purity with mass-spec identity confirmation.
• Response timeline — Sleep and subjective recovery changes (if they occur) typically appear in the first 1–2 weeks. Body-composition changes (if any) are slower, typically 8–12 weeks, and are virtually impossible to attribute to the peptide alone without controlled conditions.
• What ipamorelin does NOT do — It is not a fat burner, not a muscle builder, and does not replicate anabolic steroid effects. It modestly elevates endogenous GH and, over time, IGF-1. Downstream body-composition effects in healthy adults with already-normal GH/IGF-1 are small and hard to demonstrate.
• Red flags to stop — Persistent peripheral edema, new carpal tunnel symptoms, morning joint stiffness, fasting glucose drift, unexplained new lumps, or persistent sleep disruption. Any persistent new symptom on an unapproved compound warrants cessation first and medical evaluation second.
• Stopping — No taper needed. Plasma half-life is ~2 hours, effects wash out within a day. IGF-1 returns to baseline over days to weeks depending on cycle length and stack composition.

Commonly Stacked With

→ Check compound compatibility in the Stack Builder

Regulatory Status

Related Compounds

People researching ipamorelin often also look at these:

Next Steps

Key References

1. Raun K, Hansen BS, Johansen NL, Thøgersen H, Madsen K, Ankersen M, Andersen PH. Ipamorelin, the first selective growth hormone secretagogue. Eur J Endocrinol. 1998;139(5):552-561. PMID: 9849822. (The foundational discovery paper; establishes the selectivity claim.)
2. Gobburu JVS, Agersø H, Jusko WJ, Ynddal L. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharm Res. 1999;16(9):1412-1416. PMID: 10496658.
3. Rasmussen MH, Søgaard B, Ynddal L, et al. Ipamorelin — a new and very potent growth hormone secretagogue. Growth Horm IGF Res. 1998;8(4):332 (Abstract P-11).
4. Svensson J, Lall S, Dickson SL, Bengtsson BA, Rømer J, Ahnfelt-Rønne I, Ohlsson C, Jansson JO. The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats. J Endocrinol. 2000;165(3):569-577. PMID: 10828840.
5. 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. Int J Colorectal Dis. 2014;29(12):1527-1534. PMID: 25331030.
6. Greenwood-Van Meerveld B, Tyler K, Mohammadi E, Pietra C. Efficacy of ipamorelin, a ghrelin mimetic, on gastric dysmotility in a rodent model of postoperative ileus. J Exp Pharmacol. 2012;4:149-155. PMID: 27186126.
7. Hansen BS, Raun K, Nielsen KK, Johansen PB, Hansen TK, Peschke B, et al. Pharmacological characterization of a new oral GH secretagogue, NN703. Eur J Endocrinol. 1999;141(2):180-189. PMID: 10427165. (Novo Nordisk GHS chemistry context.)
8. Ishida J, Saitoh M, Ebner N, Springer J, Anker SD, von Haehling S. Growth hormone secretagogues: history, mechanism of action, and clinical development. JCSM Rapid Commun. 2020;3(1):25-37. doi: 10.1002/rco2.9.
9. Sigalos JT, Pastuszak AW. The Safety and Efficacy of Growth Hormone Secretagogues. Sex Med Rev. 2018;6(1):45-53. PMID: 28526632.
10. Bowers CY. Unnatural growth hormone-releasing peptide begets natural ghrelin. J Clin Endocrinol Metab. 2001;86(4):1464-1469. PMID: 11297568.
11. Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999;402(6762):656-660. PMID: 10604470. (Endogenous ligand at the GHS-R1a receptor that ipamorelin mimics.)
12. Ghigo E, Arvat E, Giordano R, et al. Biologic activities of growth hormone secretagogues in humans. Endocrine. 2001;14(1):87-93. PMID: 11322506.
13. Arvat E, Di Vito L, Maccagno B, et al. Effects of GHRP-2 and hexarelin, two synthetic GH-releasing peptides, on GH, prolactin, ACTH and cortisol levels in man. Comparison with the effects of GHRH, TRH and hCRH. Peptides. 1997;18(6):885-891. PMID: 9285939.
14. Sinha DK, Balasubramanian A, Tatem AJ, Rivera-Mirabal J, Yu J, Kovac J, et al. Beyond the androgen receptor: the role of growth hormone secretagogues in the modern management of body composition in hypogonadal males. Transl Androl Urol. 2020;9(Suppl 2):S149-S159. PMID: 32257855.
15. Veldhuis JD, Keenan DM. Secretagogues govern GH secretory-burst waveform and mass in healthy eugonadal and short-term hypogonadal men. Eur J Endocrinol. 2008;159(5):547-554. PMID: 18728125.
16. Nass R, Pezzoli SS, Oliveri MC, Patrie JT, Harrell FE Jr, Clasey JL, et al. Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults. Ann Intern Med. 2008;149(9):601-611. PMID: 18981485. (MK-677 comparator data.)
17. ClinicalTrials.gov. Study of IPAMORELIN on the Management of Postoperative Ileus Following Partial Bowel Resection. NCT00672074.
18. World Anti-Doping Agency. The 2026 Prohibited List. Section S2 — Peptide Hormones, Growth Factors, Related Substances and Mimetics. wada-ama.org.
19. U.S. Food and Drug Administration. Bulk Drug Substances That Raise Significant Safety Risks (Category 2) Under Section 503A / 503B. FDA.gov. Updated 2025.