Ipamorelin
10mg
A synthetic peptide that stimulates the pituitary to release growth hormone naturally — without raising cortisol, ACTH, or prolactin like other compounds in its class. Studied for its effects on body composition, bone density, and metabolic health, with a uniquely clean hormonal profile that makes it one of the most researched GH secretagogues available.
The first selective
GH secretagogue.
A synthetic pentapeptide that activates the ghrelin receptor to produce clean, pulsatile GH release — without the cortisol, ACTH, or prolactin elevation that limits every other compound in its class. Studied across body composition, bone density, GI motility, and GH-axis pharmacology.
Raun et al. Eur J Endocrinol 1998 · Beck et al. Int J Colorectal Dis 2014. All data from peer-reviewed literature. For Research Use Only — Not for Human Consumption.
Manufactured in US
US-formulated & filled
Endotoxin Tested
<0.05 EU/mL verified
Independently Tested
Horizon Analytical · 6-panel COA
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Ipamorelin is supplied exclusively for qualified in vitro laboratory research. Not for human administration.
This product is a research-grade synthetic pentapeptide supplied under research use only (RUO) designation. It is not approved by the FDA for any therapeutic indication in the United States. By purchasing, the buyer represents they are a qualified researcher using this compound solely for lawful in vitro laboratory research. Not a drug, dietary supplement, food, or medical device. For Research Use Only — Not for Human Consumption.
GH. Just GH.
Nothing else.
Every GH secretagogue before ipamorelin came with baggage — elevated cortisol, ACTH spikes, prolactin, appetite stimulation. Ipamorelin was the first to deliver GH release without activating those secondary pathways, even at doses 200x above the GH effective dose.
This selectivity is what makes ipamorelin the reference compound for clean GH-axis research. In research models where isolated GH-pulse dynamics are the variable of interest, confounding cortisol or ACTH co-elevation is eliminated by design.
ACTH — Not elevated
No significant ACTH release even at 200× GH ED50. GHRP-2 and GHRP-6 both significantly elevate ACTH at GH-effective doses.
Cortisol — Not elevated
Cortisol levels indistinguishable from GHRH baseline in Raun et al. swine studies. GHRP-6 and GHRP-2 both produce significant cortisol co-elevation.
Prolactin — Not elevated
No FSH, LH, PRL, or TSH changes observed at any dose tested. Ipamorelin leaves the entire hypothalamic-pituitary axis intact except for GH.
Raun K et al., Eur J Endocrinol 1998;139(5):552–561. PMID: 9849822. Preclinical data — research use only.
Selectivity Comparison — Published Data
5
residues.
Precision
designed.
Ipamorelin's five amino acids are not arbitrary — each position was specifically selected through medicinal chemistry to achieve GHS-R1a binding with the hormonal selectivity profile no other GHRP had achieved. Three of the five use non-standard amino acids that do not appear in the natural proteome.
Primary Sequence — 5 Residues
MW free base
amino acids
amidated
Raun et al.
Raun et al. Eur J Endocrinol 1998 · CAS 170851-70-4 · Novo Nordisk A/S. Research use only.
GHS-R1a binding.
Four downstream outputs.
Ipamorelin activates the ghrelin receptor (GHS-R1a) via Gq/11 coupling — a different signaling pathway than GHRH, which acts through Gs. This mechanistic independence is what makes ipamorelin + CJC-1295 combinations supra-additive: they activate complementary pathways to the same endpoint.
GHS-R1a Binding → Gαq/11 Activation
Ipamorelin binds GHS-R1a — the ghrelin receptor — with high affinity. D-2-Nal and D-Phe at positions 3–4 drive receptor engagement. Gαq/11 coupling (not Gs) distinguishes this from GHRH receptor pharmacology, enabling parallel activation when combined with GHRH-pathway peptides.
PLC → IP3/DAG → Ca2+ Release → GH Exocytosis
Gαq/11 activates phospholipase C (PLC) → IP3 triggers calcium release from intracellular stores → DAG activates PKC → GH granule exocytosis from pituitary somatotrophs. GH peak appears at ~40 minutes post-administration in human PK models (Gobburu et al. 1999).
Pulsatile GH → IGF-1 Axis → Peripheral Effects
GH pulse acts on hepatocytes (IGF-1 synthesis), bone (periosteal formation), skeletal muscle (anabolism), and adipose tissue (lipolysis). Bone mineral density increase documented in 8-week rat studies (Svensson et al. 2000). Fat mass reduction with lean mass preservation in diet-induced obese models.
Somatostatin Suppression → Disinhibited GH Release
Ipamorelin also acts at the hypothalamic level to reduce somatostatin (SS) release — removing the inhibitory brake on GH secretion. This dual action (direct pituitary stimulation + hypothalamic SS suppression) produces the characteristic rapid, high-amplitude GH pulse observed in PK studies.
Research Endpoint Areas
Pulsatile GH Release — Somatotroph Cell Models
GH quantification via RIA or ELISA in conditioned media from GC cells or primary pituitary cultures. GH peak ~40 min (Gobburu 1999). Measurable cAMP response via HTRF assay as upstream readout.
Bone Mineral Density — Cortical Bone Formation
8-week ipamorelin in female rats: increased cortical BMD and periosteal bone formation rate without adverse resorption markers (Svensson et al. 2000). Measurable via DXA or histomorphometry in preclinical models.
Body Composition — Fat Mass / Lean Mass
In diet-induced obese rat models, ipamorelin reduced fat mass while preserving lean body mass. IGF-1 ELISA as downstream readout; adipocyte lipolysis measurable via glycerol and FFA release assays.
GI Motility — Postoperative Ileus Models
Phase 2 RCT (Beck et al. 2014, n=87): ipamorelin evaluated for postoperative ileus after bowel resection — the most rigorous published human study to date, though primary endpoint was not met. GI transit and motility assays are an established research endpoint.
Full specification.
Molecular and analytical data from peer-reviewed literature and Trident Labs batch records.
Long-term
-20°C
Lyophilized sealed. Stable 24 months. Avoid frost-free freezers.
In solution
4°C
Stable 7–14 days. Single-use aliquots recommended.
Solvent
PBS / H2O
Sterile water or PBS pH 7.0–7.4. Typical stock 0.5–1 mg/mL.
Avoid
Oxidants
Protect from UV light. Use amber vials post-reconstitution.
For Research Use Only — Not for Human Consumption. Ipamorelin supplied exclusively for in vitro laboratory research. Not a drug, dietary supplement, or medical device. For lawful in vitro research use only by qualified researchers.
| Common Name | Ipamorelin / NNC 26-0161 |
| Sequence | Aib-His-D-2-Nal-D-Phe-Lys-NH2 |
| CAS Number | 170851-70-4 |
| Molecular Formula | C38H49N9O5 |
| Molecular Weight | 711.85 Da |
| Structure | Synthetic pentapeptide · 3 non-standard amino acids · C-terminal amide |
| Primary Target | GHS-R1a (ghrelin receptor) — Gαq/11-coupled GPCR |
| Signaling | GHS-R1a → Gαq/11 → PLC → IP3/DAG → Ca2+ → GH exocytosis |
| GH Selectivity | No ACTH, cortisol, or prolactin elevation even at 200× GH ED50 |
| GH Tmax | ~40 min post-administration (human PK, Gobburu et al. 1999) |
| Origin | Developed by Novo Nordisk A/S (1990s) — first described Raun et al. 1998 |
| Form | Lyophilized powder · sealed glass vial |
| Purity | ≥99% HPLC · Mass Spec verified · 6-panel COA · Horizon Analytical |
| Endotoxin | <0.05 EU/mL · LAL-tested · Horizon Analytical |
| Solubility | Water, PBS · 0.5–1 mg/mL stock |
| Regulatory | RUOIn Vitro Research Use Only — Not for Human Consumption |
Indexed research on Ipamorelin.
Independent peer-reviewed studies. Not Trident Labs claims. For Research Use Only.
Ipamorelin, the First Selective Growth Hormone Secretagogue
Raun K, Hansen BS, Johansen NL, Thogersen H, et al.
The foundational 1998 paper establishing ipamorelin as the first selective GH secretagogue. Pentapeptide Aib-His-D-2-Nal-D-Phe-Lys-NH2 was characterized in rats and conscious swine. GH ED50 = 2.3 nmol/kg in swine, comparable to GHRP-6 (3.9 nmol/kg). Critically: GHRP-6 and GHRP-2 both elevated ACTH and cortisol significantly; ipamorelin did not elevate ACTH or cortisol at doses more than 200-fold above GH ED50. No FSH, LH, PRL, or TSH changes at any dose. Conclusion: "ipamorelin is the first GHRP-receptor agonist with a selectivity for GH release similar to that displayed by GHRH." PMID: 9849822.
Efficacy of Ipamorelin in a Phase 2 RCT of Postoperative Ileus
Beck DE, Sweeney WB, McCarter MD, et al.
The most rigorous published human study of ipamorelin to date. n=87 patients undergoing bowel resection surgery, randomized to ipamorelin vs placebo for postoperative ileus management. Primary endpoint: time to GI recovery. Ipamorelin was safe and well-tolerated; the primary endpoint was not statistically met in this trial. The study is significant as the first formal Phase 2 RCT of ipamorelin in humans, providing human safety and PK data in a surgical setting. PMID: 25331030.
Ipamorelin Increases Bone Mineral Density in Female Rats
Svensson J, Lall S, Dickson SL, et al.
8-week administration of ipamorelin in female rats produced increased cortical bone mineral density and periosteal bone formation rate without adverse changes in bone resorption markers. Study provides mechanistic basis for ipamorelin's research interest in bone biology — the GH/IGF-1 axis is a well-established regulator of bone turnover, and ipamorelin's selective GH stimulation without cortisol elevation is particularly relevant since glucocorticoids are bone-catabolic. PMID: 11008979.
Pharmacokinetic-Pharmacodynamic Modeling of Ipamorelin in Human Volunteers
Gobburu JV, Agersoe H, Jusko WJ, Ynddal L.
PK/PD modeling of ipamorelin following IV administration in healthy human volunteers. GH peak concentration (Tmax) documented at approximately 40 minutes post-administration. PK/PD model characterized the dose-GH response relationship for research context. First human pharmacokinetic characterization of ipamorelin, establishing the quantitative relationship between plasma ipamorelin concentrations and pituitary GH secretion dynamics. PMID: 10496658.
Ipamorelin as a Selective Ghrelin Receptor Agonist — GI Motility Rodent Model
ScienceDirect 2025.
2025 rodent model study evaluating ipamorelin for gastrointestinal transit acceleration in a postoperative ileus model. Ipamorelin demonstrated accelerated GI transit and symptom improvement in the rodent POI model. Mechanism: GHS-R1a activation drives enteric nervous system motility pathways alongside pituitary GH effects — the same ghrelin receptor is expressed in both the pituitary and the GI tract. Provides updated preclinical evidence for GI research applications. ScienceDirect 2025.
Ipamorelin: Complete Research Guide — Selective GH Secretagogue
Spartan Peptides Research Team.
2026 comprehensive review covering ipamorelin's sequence engineering rationale, GHS-R1a pharmacology, selectivity mechanism, and published research evidence base. Reviews bone BMD data (Svensson 2000), body composition data in obese rat models, GI motility evidence, and the mechanistic basis for CJC-1295 combination research models. Covers selectivity comparison against GHRP-2, GHRP-6, hexarelin, and MK-677. April 2026.
Independent peer-reviewed research — not Trident Labs claims. Ipamorelin is supplied for in vitro research use only. Not for human consumption.
References
Raun K, Hansen BS, Johansen NL, Thogersen H, et al.
Ipamorelin, the first selective growth hormone secretagogue
Beck DE, Sweeney WB, McCarter MD, et al.
Prospective, randomized, controlled, proof-of-concept study of the Ghrelin Mimetic ipamorelin for the management of postoperative ileus in bowel resection patients
Svensson J, Lall S, Dickson SL, et al.
The GH secretagogues ipamorelin and GH-releasing peptide-6 increase bone mineral content in adult female rats
Gobburu JV, Agersoe H, Jusko WJ, Ynddal L.
Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers
ScienceDirect / Venkova K et al.
Efficacy of ipamorelin, a novel ghrelin mimetic, in a rodent model of postoperative ileus
Spartan Peptides Research Team.
Ipamorelin: Complete Research Guide — Selective GH Secretagogue
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