Description
Summary Abstract
4x Blend (P-057; GHRP-2 5 MG + Tesamorelin 5 MG + MGF 500 MCG + Ipamorelin 2.5 MG; 12.5 MG total lyophilized vial) is a four-compound GH-axis and tissue-repair research formulation that activates the complete growth hormone secretagogue receptor hierarchy alongside a locally expressed IGF-1 splice variant with independent tissue-regenerative signaling. GHRP-2 (Pralmorelin; D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH₂; CAS 158861-67-7; MW 817.97 g/mol; C₄₅H₅₅N₉O₆) is a synthetic hexapeptide GHS-R1a agonist approved in Japan as a diagnostic agent for GHD and is among the most potent standard GHRPs by peak GH output, with D-amino acid substitutions conferring DPP-IV resistance. Tesamorelin (CAS 901758-09-6; MW 5,135.9 g/mol; FDA-approved GHRH analog) activates the GHRH receptor via the Gs-cAMP-PKA pathway for synergistic GH release with both GHRP-2 and Ipamorelin. MGF (Mechano Growth Factor; IGF-1 splice variant Ec/Eb E-peptide; CAS no single registry; MW ~2,867 g/mol; C₁₂₁H₂₀₀N₄₂O₃₉; sequence YQPPSTNKNTKSQRRKGSTFEERK — 24 AA) is the C-terminal E-domain peptide generated by alternative splicing of the IGF-1 gene under mechanical or hypoxic stress, proposed to activate muscle satellite cells for tissue repair upstream of mature IGF-1-driven differentiation. Ipamorelin (CAS 170851-70-4; MW 711.85 g/mol; selective GHS-R1a agonist) completes the quartet as the most selective GHRP, contributing clean GH stimulation without HPA axis co-activation. Together, the blend engages the GHRH receptor (Tesamorelin), GHS-R1a (GHRP-2 + Ipamorelin) via complementary potency/selectivity profiles, and satellite cell IGF-1Ec signaling (MGF) — a comprehensive GH-axis and tissue-repair stimulus across four mechanisms.
Clinical Research Indications
This four-compound blend supports research across GH-axis biology, body composition, and tissue regeneration:
- Comprehensive GH-Axis Stimulation: GHRP-2 and Ipamorelin provide GHS-R1a agonism through complementary potency and selectivity profiles (GHRP-2: higher peak GH output with moderate cortisol/prolactin; Ipamorelin: selective GH without HPA activation); Tesamorelin contributes independent GHRH-R stimulation — three distinct pharmacological profiles co-activating GH secretion synergistically.
- Muscle Satellite Cell Activation and Repair (MGF): MGF’s proposed mechanism activates quiescent satellite cells (muscle progenitor cells) by driving myoblast proliferation before IGF-1R-mediated differentiation, providing an upstream regenerative signal distinct from systemic GH/IGF-1 effects. Research applications include ischemia-reperfusion models, atrophy recovery, and satellite cell biology.
- Visceral Adiposity and Body Composition (Tesamorelin): As in the Tesamorelin/Ipamorelin Blend, Tesamorelin’s FDA-documented Phase 3 VAT reduction data (−15–18% over 26 weeks) informs body composition applications; the addition of GHRP-2 and Ipamorelin amplifies the GH secretory stimulus.
- GH Deficiency Provocation Models (GHRP-2): GHRP-2 is approved in Japan as a GHD diagnostic provocation agent and, alongside the GHRH analog Tesamorelin, represents a maximal combined GHRH+GHRP pituitary provocation for GHD research protocols requiring somatotroph reserve assessment.
Contraindications
- GHRP-2 — HPA Axis Effects: Unlike Ipamorelin, GHRP-2 stimulates ACTH, cortisol, and prolactin release at higher doses (typical cortisol elevation 30–50% at equipotent GH doses); research designs requiring isolated GH pathway effects should account for this HPA co-stimulation or consider the Tesamorelin/Ipamorelin Blend instead.
- MGF — Absence of Human Clinical Data: No completed human Phase 1 safety trial exists for MGF or PEG-MGF as of mid-2026; all mechanistic and efficacy data derive from rodent models and in vitro studies. The translational relevance to human physiology remains unestablished — protocols should reflect this preclinical evidence base.
- Active Neoplasia / IGF-1-Sensitive Tumors: The combination of GH-axis stimulation (GHRP-2, Tesamorelin, Ipamorelin) and IGF-1 splice variant signaling (MGF) warrants caution in oncological research settings; use in subjects with active malignancy requires specialized oversight.
- Tachyphylaxis (GHRP-2 and Ipamorelin): Both GHS-R1a agonists undergo receptor desensitization with continuous use; research designs should include cycling protocols and should track GH response amplitude over time in sustained-dosing experiments.
Mechanism of Action (MOA)
The 4x Blend engages four distinct mechanistic axes across the GH secretagogue receptor system and the IGF-1 splice variant signaling pathway:
GHRP-2 — Potent GHS-R1a Agonism (Gαq/11 / Ca²⁺ / PLC)
GHRP-2 activates GHS-R1a via Gαq/11-PLCβ-IP3-Ca²⁺ signaling with high potency (EC₅₀ ~0.1–1 nM; peak GH at 15–30 minutes; 8–20× above baseline at 100–300 µg doses). It produces the highest standard peak GH output of any GHRP in this blend, at the cost of moderate cortisol/ACTH co-stimulation. The D-amino acids (D-Ala at position 1, D-2-Nal at position 2, D-Phe at position 5) provide DPP-IV resistance extending effective activity. GHRP-2 also interacts with CD36 and has documented direct anti-atrophy effects on myocytes (suppression of muscle atrophy genes) and anti-inflammatory actions (reduction of pro-inflammatory cytokines) independent of GH release.
Tesamorelin — GHRH-R Agonism (Gs / cAMP / PKA) — Synergistic GH
Tesamorelin provides the GHRH receptor (Gs-cAMP-PKA) arm of the dual-pathway synergy. Its Phase 3 VAT selectivity data establish the downstream metabolic consequence of this GH secretion: selective visceral lipolysis via GH/IGF-1-driven hormone-sensitive lipase and adipose triglyceride lipase activation. Combined with both GHRP-2 and Ipamorelin’s GHS-R1a stimulation, Tesamorelin’s GHRH-R agonism produces three-way convergence at the somatotroph — the cAMP-dependent pathway counteracting somatostatin while the Ca²⁺-dependent pathways drive direct vesicle exocytosis. See individual page: Tesamorelin.
MGF — IGF-1Ec E-Peptide: Satellite Cell Activation and Local Tissue Repair
MGF (Mechano Growth Factor) is the C-terminal 24-amino acid E-domain peptide produced when the IGF-1 gene is alternatively spliced to the IGF-1Ec isoform under mechanical stress or hypoxia. In contrast to systemic mature IGF-1 (which drives myocyte differentiation via IGF-1R), MGF’s E-peptide has been proposed to act upstream — driving proliferation of quiescent muscle satellite cells (MuSCs) before differentiation is committed. Satellite cell activation is the rate-limiting step of skeletal muscle repair after injury; MGF’s preclinical data in rodent models demonstrate satellite cell proliferation, protection of cardiomyocytes from ischemia-reperfusion injury, and neuroprotective effects. Native MGF has a half-life of minutes; PEGylated MGF (~48–72 hours) is used for extended-exposure research protocols.
Ipamorelin — Selective GHS-R1a Agonism: Clean GH Without HPA Co-Activation
Ipamorelin provides selective GHS-R1a agonism (Gαq/11-PLCβ-Ca²⁺) with exceptional hormonal specificity — no significant ACTH, cortisol, or prolactin elevation even at 200× the GH ED₅₀ (Raun et al., 1998). Within the 4x Blend, Ipamorelin’s role is to contribute additive GHS-R1a stimulation while maintaining overall HPA selectivity. GHRP-2 provides the amplitude peak; Ipamorelin provides the selectivity anchor. Together with Tesamorelin’s GHRH-R activation, all three converge at the somatotroph for maximum dual-pathway GH release within an acceptably selective hormonal profile. See individual page: Ipamorelin.
Key Features & Specifications
Defining characteristics of this comprehensive four-compound GH-axis and tissue-repair blend:
Chemical Analysis
| Property | Specification Reference Data |
|---|---|
| Component 1 — GHRP-2 | Synthetic hexapeptide; D-Ala-D-2-Nal-Ala-Trp-D-Phe-Lys-NH₂ (6 AA; C-terminal amide; D-amino acids for DPP-IV resistance); synonyms: Pralmorelin; KP-102 |
| GHRP-2 CAS | 158861-67-7 |
| GHRP-2 Molecular Formula | C45H55N9O6 |
| GHRP-2 Molecular Weight | 817.97 g/mol |
| GHRP-2 PubChem CID | 6918245 |
| GHRP-2 Half-Life | ~20–30 minutes |
| Component 2 — Tesamorelin | Synthetic GHRH(1-44) analog; 44 AA; trans-3-hexenoic acid N-terminal modification; see Product 4 for full data |
| Tesamorelin CAS | 901758-09-6 |
| Tesamorelin Molecular Weight | 5,135.9 g/mol |
| Component 3 — MGF | Mechano Growth Factor; IGF-1Ec E-domain peptide; YQPPSTNKNTKSQRRKGSTFEERK (24 AA; human native sequence); C-terminal Cys or Lys depending on variant; IGF-1 splice variant Ec in humans |
| MGF Molecular Formula | C121H200N42O39 |
| MGF Molecular Weight | ~2,867 g/mol (24-AA native E-peptide) |
| MGF Synonyms | Mechano Growth Factor; IGF-1 Ec/Eb E-domain peptide; IGF-1Ec (human) |
| MGF Half-Life | Minutes (native); ~48–72 hours (PEGylated PEG-MGF variant) |
| Component 4 — Ipamorelin | Selective pentapeptide GHS-R1a agonist; Aib-His-D-2-Nal-D-Phe-Lys-NH₂; see Product 4 for full data |
| Ipamorelin CAS | 170851-70-4 |
| Ipamorelin Molecular Weight | 711.85 g/mol |
| Form / Variation | 12.5 MG Lyophilized Blend Vial (P-057) — 5 MG GHRP-2 + 5 MG Tesamorelin + 500 MCG MGF + 2.5 MG Ipamorelin |
Storage, Safety, and Handling
Storage Protocol
Store lyophilized blend at −20 °C, protected from light. MGF’s native E-peptide sequence is subject to rapid enzymatic degradation in biological fluids (half-life of minutes); however, as a lyophilized solid it is stable at −20 °C. Once reconstituted with bacteriostatic water for injection, store at 2–8 °C and use within 21 days; avoid repeated freeze-thaw cycles of the reconstituted solution. GHRP-2 and Ipamorelin contain tryptophan residues that are susceptible to UV-induced oxidation — store reconstituted solution in amber vials.
Handling & Compliance
Handle with standard laboratory PPE and aseptic reconstitution technique. The blend includes GHRP-2, which produces cortisol/ACTH co-stimulation at higher doses; protocols sensitive to HPA axis perturbation should factor this in. MGF has no completed human clinical trial data — institutional ethics oversight is required for any human-adjacent research. All four components are prohibited under WADA: GHRP-2 (S2), Tesamorelin (S2), Ipamorelin (S2), and MGF (S2 — growth factors and related substances). GH-axis research designs should include cycling protocols to mitigate GHS-R1a tachyphylaxis from continuous GHRP-2 and Ipamorelin use.