Research Applications
Growth Hormone Deficiency Diagnosis
GHRP-2 (pralmorelin) is approved in Japan for diagnostic evaluation of pituitary GH secretory reserve. The GHRP-2 stimulation test is considered reliable, with a GH peak cutoff of <9-15 ng/mL indicating GH deficiency, depending on the protocol.
Body Composition Enhancement
Research demonstrates GHRP-2 increases GH and IGF-1 levels, promoting lean mass accretion and fat reduction. Studies in healthy volunteers show dose-dependent increases in 24-hour GH secretion rates, with improvements in lean body mass, nitrogen retention, and visceral fat reduction.
Sleep Architecture Enhancement
GHRP-2 administered before bedtime significantly increases stage 3/4 slow-wave sleep duration and GH pulse amplitude during sleep. This makes it particularly researched for recovery optimization and age-related sleep deterioration.
Cardiac Protection Research
Studies demonstrate GHRP-2's cardioprotective effects independent of GH release, including reduced infarct size in ischemia-reperfusion models, improved left ventricular function, and anti-fibrotic effects in cardiac tissue.
Muscle Wasting Conditions
Research in catabolic states (burns, sepsis, AIDS-related wasting) shows GHRP-2 preserves lean body mass and improves nitrogen balance through GH-mediated protein anabolism.
Bone Metabolism
GHRP-2-stimulated GH and IGF-1 elevations enhance osteoblast activity and bone formation. Preclinical studies show improved bone mineral density and enhanced fracture healing.
Mechanism of Action
GHS-R1a Receptor Agonism
GHRP-2 binds to the growth hormone secretagogue receptor 1a (GHS-R1a) on anterior pituitary somatotrophs, activating Gq/11-mediated phospholipase C signaling. This generates IP3 and DAG, triggering calcium release from intracellular stores and activating PKC. The calcium surge drives exocytosis of stored GH granules.
Hypothalamic GHRH Potentiation
Beyond direct pituitary action, GHRP-2 stimulates hypothalamic GHRH neurons, increasing endogenous GHRH secretion. This dual mechanism — direct pituitary stimulation plus enhanced GHRH release — contributes to the robust GH response. GHRP-2 also suppresses hypothalamic somatostatin tone, removing the primary brake on GH secretion.
Cortisol and Prolactin Stimulation
Unlike more selective agents, GHRP-2 activates ACTH secretion at the pituitary level, leading to transient cortisol elevations (typically 15-30% increase). It also stimulates prolactin release through pituitary lactotroph GHS-R1a activation. These effects are dose-dependent and more pronounced than with ipamorelin.
Appetite Stimulation
Through hypothalamic GHS-R1a activation, GHRP-2 stimulates appetite — mimicking endogenous ghrelin's orexigenic effects. This involves activation of NPY/AgRP neurons in the arcuate nucleus and suppression of POMC signaling. The appetite stimulation is moderate — less than GHRP-6 but more than ipamorelin.
Cardioprotective Effects
GHRP-2 has demonstrated direct cardioprotective activity independent of GH release, acting on cardiac GHS-R1a receptors to reduce apoptosis and improve contractile function in ischemic conditions. It also promotes coronary vasodilation through nitric oxide-dependent mechanisms.
Biological Pathways
PLC/IP3/DAG/Calcium Pathway
GHS-R1a activation engages Gq/11 proteins, activating phospholipase C. IP3 triggers calcium release from the ER. DAG activates PKC. The resulting calcium spike triggers GH granule fusion with the plasma membrane and exocytosis.
cAMP Cross-Talk
While GHS-R1a primarily signals through Gq/11, GHRP-2 also induces modest cAMP generation through Gαs coupling and PKC-mediated adenylyl cyclase activation. This cross-talk with the GHRH/cAMP pathway contributes to the synergistic effect when GHRP-2 is combined with GHRH analogs.
AMPK/Hypothalamic Energy Sensing
In hypothalamic neurons, GHS-R1a activation by GHRP-2 stimulates AMPK (AMP-activated protein kinase), a master energy sensor. Hypothalamic AMPK activation increases food intake (orexigenic effect) and modulates peripheral energy metabolism.
GH/IGF-1/MAPK Growth Pathway
Released GH activates ERK1/2 MAPK signaling in target tissues through JAK2-SHC-Ras activation. This pathway drives cell proliferation, differentiation, and tissue repair, complementing the IGF-1/PI3K/Akt anabolic pathway.
Dosage Information
Calculation Results
Syringe Fill Level (100u syringe)
Protocols
No protocols featuring this peptide yet.
Browse All ProtocolsStability & Storage
GHRP-2 is supplied as a lyophilized white powder. Store at -20°C for long-term stability (18-24 months) or 2-8°C for up to 6 months. Protect from light and moisture.
Reconstitute with bacteriostatic water. The resulting solution should be clear and colorless. Store reconstituted GHRP-2 at 2-8°C and use within 21-28 days. Do not freeze reconstituted solution.
GHRP-2 has moderate stability in solution, with a half-life of several hours at room temperature. The D-amino acid substitutions (D-Ala position 1, D-βNal position 2, D-Phe position 5) confer significant protease resistance compared to native peptides. In-vivo half-life is approximately 25-30 minutes after subcutaneous injection.
Side Effects & Precautions
Increased Appetite
GHRP-2 significantly stimulates appetite through hypothalamic ghrelin receptor activation. This effect peaks 20-30 minutes post-injection and can last 1-2 hours. It is less pronounced than GHRP-6 but more notable than ipamorelin.
Water Retention
Mild fluid retention, particularly in extremities and face, is common during initial use. This is a GH-mediated class effect that typically attenuates over 2-4 weeks.
Cortisol Elevation
GHRP-2 transiently increases cortisol levels by 15-30%, primarily at higher doses. While this is generally not clinically significant in healthy individuals, it distinguishes GHRP-2 from more selective agents like ipamorelin.
Prolactin Elevation
Moderate prolactin increases occur with GHRP-2 use. In most individuals, levels remain within normal range, but monitoring is advisable with chronic use, particularly in individuals prone to prolactin-related effects.
Numbness and Tingling
Carpal tunnel-like symptoms may occur with sustained GH elevation, related to fluid retention affecting nerve compression areas. Dose reduction alleviates symptoms.
Injection Site Reactions
Mild local pain and redness at injection sites are common and self-limiting.
Dizziness and Head Rush
Brief lightheadedness following injection is reported by some users and typically resolves within minutes.
Research Use Only. This information is for educational and research purposes only. Not intended for medical advice or self-medication.
Regulatory Status
GHRP-2 (pralmorelin) is approved in Japan as a diagnostic agent for growth hormone deficiency (marketed as GHRP Kaken 100). It is not approved by the FDA, EMA, or other major regulatory authorities for therapeutic use.
The peptide is classified as an investigational research compound in most countries and is available through research chemical suppliers for laboratory use. It is not approved for human therapeutic use outside of Japan's diagnostic application.
WADA prohibits GHRP-2 under category S2 (Peptide Hormones, Growth Factors, Related Substances, and Mimetics) of the prohibited list, banned both in-competition and out-of-competition.
Research Studies
Growth Hormone-Releasing Peptide-2: A Potent GH Secretagogue
Bowers CY, Momany FA, Reynolds GA, et al.
Acute and Chronic Effects of GHRP-2 on GH Secretion
Arvat E, Maccario M, Di Vito L, et al.
GHRP-2 Stimulation Test for GH Deficiency Diagnosis
Mahajan T, Lightman S.
Cardioprotective Effects of Growth Hormone-Releasing Peptides
Berlanga J, Cibrian D, Guillen I, et al.
Orexigenic Effects of GHRP-2 and Their Hypothalamic Mediators
Laferrère B, Abraham C, Russell CD, Bowers CY.
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