GHRP-2 (5mg)

GHRP-2 (5mg): A Synthetic Hexapeptide Growth Hormone-Releasing Peptide (GHRP) and Selective Agonist of the Growth Hormone Secretagogue Receptor (GHS-R1a/Ghrelin Receptor), Producing Robust Pulsatile Growth Hormone Release with Minimal Appetite Stimulation — the 5mg Vial Format Ideal for Lower-Dose Protocols, Sensitive Individuals, and Cycle Initiation, with Extensive Preclinical and Human Clinical Data Supporting Its Efficacy, GH Selectivity, and Favorable Safety Profile for Body Composition, Anti-Aging, and Recovery Applications

GHRP-2 (also known as pralmorelin, KP-102, or Growth Hormone-Releasing Peptide 2) is a synthetic hexapeptide (six-amino-acid peptide with the sequence D-Ala-D-β-Nal-Ala-Trp-D-Phe-Lys-NH2) that belongs to the growth hormone-releasing peptide (GHRP) family — a class of small peptides discovered through the pioneering research of Dr. Cyril Bowers and colleagues at Tulane University, who systematically optimized the weak GH-releasing activity of met-enkephalin into increasingly potent and selective compounds, culminating in the development of GHRP-6 (the prototypical GHRP), GHRP-2 (a more GH-selective analogue), and subsequently non-peptide GH secretagogues such as MK-0677 (ibutamoren). The mechanism of GHRP-2 was elucidated with the 1996 cloning of the growth hormone secretagogue receptor (GHS-R1a) — a G-protein-coupled receptor distinct from the GHRH receptor, expressed primarily on pituitary somatotrophs and hypothalamic arcuate nucleus neurons — and the 1999 discovery of ghrelin, the 28-amino-acid stomach-derived "hunger hormone" that is the endogenous ligand for GHS-R1a. GHRP-2 acts as a potent and selective full agonist of GHS-R1a, activating the Gq/11 → phospholipase C → IP3 → intracellular calcium mobilization pathway in somatotroph cells, triggering rapid exocytotic release of stored growth hormone in a pulsatile pattern that mimics the natural ultradian rhythm of endogenous GH secretion (peaking within 30-60 minutes after subcutaneous administration, reaching levels of 20-50+ ng/mL compared to basal <1-2 ng/mL, and returning to near-baseline within 2-4 hours). What distinguishes GHRP-2 from GHRP-6 (the prototypical GHRP) is its superior pharmacological profile: GHRP-2 has greater selectivity for GH release (producing relatively less stimulation of prolactin and ACTH/cortisol), a shorter duration of action producing a more pronounced but briefer GH pulse, and — most clinically importantly — it does not produce the significant appetite-stimulating (orexigenic) effects that characterize GHRP-6 and ghrelin (which act on hypothalamic NPY/AgRP neurons to stimulate food intake). This lack of significant appetite stimulation makes GHRP-2 particularly desirable for body composition and fat-loss applications where increased appetite would be counterproductive, and it is the reason GHRP-2 is often preferred over GHRP-6 for cutting phases, anti-aging protocols, and individuals sensitive to appetite stimulation. The 5mg vial format of GHRP-2 is ideal for lower-dose protocols (typically 100-200 mcg per dose, with a 5mg vial providing 25-50 doses), for sensitive individuals or those new to GH secretagogues who wish to start at lower doses and titrate gradually, for cycle initiation and tapering phases where lower doses are appropriate, and for those who prefer more frequent smaller dosing (2-3 times daily) to produce multiple GH pulses throughout the day rather than fewer larger doses. The downstream effects of GHRP-2-induced GH and IGF-1 elevation are broad and well-documented: increased protein synthesis and lean muscle mass (anabolic effects mediated primarily by IGF-1), increased lipolysis and reduced body fat particularly visceral fat (GH is a potent lipolytic hormone that opposes insulin action on fat storage), improved bone density and bone remodeling, enhanced tissue repair and wound healing, improved sleep quality particularly deep slow-wave sleep (during which the largest endogenous GH pulses occur), improved skin elasticity and hydration, potential cardioprotective effects, and potential anti-aging and longevity effects (since GH/IGF-1 levels decline progressively with age — "somatopause" — and restoring more youthful levels may have beneficial effects on body composition, energy, recovery, and vitality). GHRP-2 also acts synergistically with GHRH analogues such as CJC-1295 and Mod-GRF 1-29: when administered together, the GH response to the combination is substantially greater than the sum of individual responses (supra-additive synergy), because GHRH activates the cAMP/PKA pathway promoting GH synthesis and priming somatotrophs for release, while GHRP-2 activates the Gq/PLC/calcium pathway triggering actual GH exocytosis, and GHRP-2 also inhibits hypothalamic somatostatin (the primary inhibitor of GH release), removing the "brake" on GH secretion. This synergy is the basis for the common practice of combining GHRP-2 with CJC-1295 or Mod-GRF 1-29 — considered the most effective pharmacological approach to stimulating endogenous, pulsatile GH release. In human clinical studies, GHRP-2 (pralmorelin) has been extensively studied and is approved in Japan and some countries as a diagnostic agent for GH deficiency (the GHRP-2 stimulation test), with a generally favorable safety profile; common side effects are typically mild and transient including flushing, mild headache, paresthesia (numbness/tingling), occasional water retention at high doses, and minimal appetite stimulation (distinguishing it from GHRP-6). As of 2026, GHRP-2 is not FDA-approved as a therapeutic in the United States and is available primarily as a research-grade peptide for laboratory and investigational use. The research-grade GHRP-2 supplied by Amideworks is intended for laboratory and investigational use only, not for human consumption or therapeutic use^{[1][2][3][4][5][6][7][8][9][10]}.

Understanding GHRP-2: Mechanism, Pharmacology, and the 5mg Vial

To fully appreciate GHRP-2 and its appropriate use in research settings, it is essential to understand its molecular mechanism, its pharmacological profile relative to other GHRPs, the rationale for the 5mg vial format, and the key considerations that researchers and investigators should keep in mind when working with this compound. At the molecular level, GHRP-2 is a hexapeptide with the sequence D-Ala-D-β-Nal-Ala-Trp-D-Phe-Lys-NH2 — containing two D-amino acids (D-alanine at position 1 and D-phenylalanine at position 5) that confer metabolic stability by resisting proteolytic degradation by peptidases that recognize L-amino acid peptide bonds, one unnatural amino acid (D-β-Nal, or D-3-(2-naphthyl)alanine, at position 2) that contributes significantly to the peptide's high receptor affinity and GH-releasing potency, and a C-terminal amide group that is important for receptor binding and biological activity. The molecular weight is approximately 817 Da, and the peptide is freely soluble in sterile water or bacteriostatic water for reconstitution. GHRP-2 binds to and acts as a full agonist of GHS-R1a — a class A (rhodopsin-like) G-protein-coupled receptor with seven transmembrane domains, expressed primarily in two key locations: (1) on somatotroph cells (the growth hormone-producing cells, which constitute approximately 40-50% of anterior pituitary cells) in the anterior pituitary gland, where GHS-R1a activation directly stimulates GH release; and (2) in the hypothalamus, particularly in the arcuate nucleus, where GHS-R1a is expressed on somatostatin neurons (which produce somatostatin, the primary inhibitor of GH release) and — to a lesser extent than with GHRP-6 or ghrelin — on NPY/AgRP neurons (the primary orexigenic/appetite-stimulating neurons). Upon agonist binding, GHS-R1a undergoes a conformational change that activates its associated Gq/11 heterotrimeric G-protein, leading to activation of phospholipase C-β (PLC-β), hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) into inositol 1,4,5-trisphosphate (IP3) and diacylglycerol (DAG), IP3-mediated release of stored calcium from the endoplasmic reticulum into the cytosol, and the resulting rapid increase in intracellular calcium concentration that triggers exocytotic release of growth hormone from secretory granules in somatotroph cells. DAG activates protein kinase C (PKC), which may contribute to the sustained phase of GH release and longer-term effects including increased GH gene transcription. The net result is a rapid, dose-dependent, pulsatile release of GH — with the pulsatile pattern being physiologically important because endogenous GH secretion is naturally pulsatile (occurring in approximately 6-12 pulses per 24 hours, with the largest pulses during the first few hours of deep slow-wave sleep), and pulsatile GH exposure is associated with more physiological effects and potentially less risk of receptor desensitization or adverse metabolic effects compared to constant, non-pulsatile GH exposure (as can occur with high-dose exogenous GH or long-acting secretagogues like MK-0677). The 5mg vial format of GHRP-2 is particularly well-suited for several common research scenarios: (1) Lower-dose protocols — typical research doses of GHRP-2 range from 100-300 mcg (0.1-0.3 mg) per administration, and a 5mg vial provides 17-50 individual doses depending on the dose used, making it economical and convenient for extended research protocols; (2) Sensitive individuals and cycle initiation — those new to GH secretagogues or particularly sensitive to their effects often prefer to start at lower doses (e.g., 50-100 mcg) and titrate gradually to assess tolerance, and the 5mg vial provides sufficient material for this gradual initiation without the waste of a larger vial; (3) Multiple daily dosing — because GHRP-2 produces a relatively brief GH pulse (2-4 hours), some research protocols use 2-3 administrations per day (typically upon waking, post-workout, and before bed) to produce multiple GH pulses and more sustained IGF-1 elevation, and the 5mg vial supports this frequent dosing pattern; (4) Cycle tapering — at the end of a research cycle, lower doses are often used for tapering, and the 5mg vial is convenient for this phase; (5) Combination protocols — when GHRP-2 is used in combination with a GHRH analogue (CJC-1295 or Mod-GRF 1-29), the GHRP-2 dose is often kept at the lower end (100-150 mcg) because the synergy with GHRH produces a much larger GH response than GHRP-2 alone, and the 5mg vial is well-suited for these lower combination doses. Reconstitution of the 5mg vial is straightforward: add 2-5 mL of bacteriostatic water (or sterile water for immediate use) to the vial, resulting in concentrations of 2.5-1 mg/mL respectively; for example, adding 2.5 mL of bacteriostatic water to a 5mg vial yields a concentration of 2 mg/mL, so a 100 mcg dose = 0.05 mL (5 units on an insulin syringe), a 150 mcg dose = 0.075 mL, and a 200 mcg dose = 0.1 mL. Reconstituted GHRP-2 is stable for 14-30 days when refrigerated at 4°C and protected from light, and should not be frozen (repeated freeze-thaw cycles can degrade the peptide); for longer storage, the lyophilized powder should be kept at -20°C, protected from light and moisture, where it remains stable for 24 months from the date of manufacture. When working with GHRP-2 in research settings, several important considerations merit emphasis: (a) GHRP-2 requires functional pituitary somatotroph cells to be effective — unlike exogenous recombinant GH (which directly supplies GH regardless of pituitary function), GHRP-2 stimulates the release of endogenous GH from pituitary somatotrophs and therefore cannot produce a GH response in individuals with severe pituitary damage or complete GH deficiency where there are no functional somatotroph cells; (b) the pulsatile pattern of GH release produced by GHRP-2 is considered more physiological than the sustained elevation produced by exogenous recombinant GH or long-acting secretagogues, and may be associated with fewer adverse metabolic effects (less insulin resistance, less edema) at equivalent GH/IGF-1 levels; (c) the synergy with GHRH analogues is robust and well-documented — the combination of GHRP-2 (100-150 mcg) + CJC-1295 or Mod-GRF (100-200 mcg) typically produces a GH response 2-5 times greater than the sum of individual responses, and this combination is considered the gold standard for pharmacological stimulation of endogenous, pulsatile GH release; (d) the lack of significant appetite stimulation is a key advantage of GHRP-2 over GHRP-6, particularly for fat-loss and body composition applications where increased appetite would be counterproductive — although at very high doses some appetite stimulation may occur, it is typically minimal compared to GHRP-6; (e) the safety profile is generally favorable with common side effects being mild and transient (flushing, headache, paresthesia, occasional water retention at high doses), but theoretical concerns include insulin resistance at high doses (GH is a counter-regulatory hormone), potential effects on pre-existing tumors (GH/IGF-1 are mitogenic), and potential suppression of endogenous GH with chronic high-dose use (not consistently observed with pulsatile GHRP-2) — these concerns are primarily theoretical at physiological replacement doses but warrant careful consideration in research design^{[1][2][3][4][5][6][7][8][9][10]}.

1. GHS-R1a receptor agonism — the molecular mechanism: GHRP-2 (sequence: D-Ala-D-β-Nal-Ala-Trp-D-Phe-Lys-NH2, MW ~817 Da) is a potent, selective full agonist of the growth hormone secretagogue receptor 1a (GHS-R1a) — the same receptor endogenously activated by ghrelin (the "hunger hormone" from the stomach). GHS-R1a is a class A GPCR expressed on pituitary somatotrophs and hypothalamic arcuate nucleus neurons. Activation triggers Gq/11 → phospholipase C-β → IP3 → intracellular calcium mobilization → exocytotic GH release from somatotroph secretory granules. The result is rapid, pulsatile GH elevation (peak 30-60 min SC, 20-50+ ng/mL vs basal <1-2, duration 2-4 hr) that mimics the natural ultradian rhythm of endogenous GH secretion — considered more physiological than constant GH exposure and associated with fewer adverse metabolic effects.
2. Superior GH selectivity and minimal appetite stimulation — the key advantages over GHRP-6: GHRP-2 is distinguished from GHRP-6 (the prototypical GHRP) by three important pharmacological differences: (a) Greater GH selectivity — GHRP-2 produces relatively less stimulation of other pituitary hormones (prolactin, ACTH/cortisol), meaning the GH response is more "pure"; (b) Shorter duration — GHRP-2 produces a more pronounced but briefer GH pulse (2-4 hr vs 3-6 hr for GHRP-6), which may be advantageous for producing a more physiological pulsatile pattern; (c) Minimal appetite stimulation — this is the most clinically important difference: GHRP-6 (like ghrelin) produces significant orexigenic (appetite-stimulating) effects through activation of GHS-R1a on hypothalamic NPY/AgRP neurons, leading to increased food intake and potential fat gain, whereas GHRP-2 produces minimal or no significant appetite stimulation at therapeutic doses — making GHRP-2 particularly desirable for fat-loss, body composition, and anti-aging applications where increased appetite would be counterproductive.
3. Synergy with GHRH analogues (CJC-1295 / Mod-GRF 1-29) — the gold standard combination: GHRP-2 acts synergistically with GHRH and GHRH analogues to produce a supra-additive GH response (typically 2-5 times greater than the sum of individual responses). This synergy occurs through three complementary mechanisms: (a) GHRH activates the GHRH receptor (GHRHR, class B GPCR) → Gs → adenylyl cyclase → cAMP → PKA, which increases GH synthesis and "primes" somatotrophs for release; (b) GHRP-2 activates GHS-R1a → Gq → PLC → IP3 → calcium, which triggers the actual exocytotic release of GH; (c) GHRP-2 also inhibits hypothalamic somatostatin release (somatostatin is the primary inhibitor of GH secretion), removing the "brake" on GH release and amplifying the effect of GHRH. The typical research combination is GHRP-2 (100-150 mcg) + CJC-1295 or Mod-GRF (100-200 mcg), administered 2-3 times daily — this is considered the most effective pharmacological approach to stimulating endogenous, pulsatile GH release, and the 5mg vial of GHRP-2 is well-suited for these lower combination doses (100-150 mcg = 33-50 doses per 5mg vial).
4. The 5mg vial — ideal for lower-dose protocols, sensitive individuals, and cycle management: The 5mg vial format of GHRP-2 is particularly well-suited for: (a) Lower-dose protocols — typical research doses are 100-300 mcg (0.1-0.3 mg), and a 5mg vial provides 17-50 individual doses, making it economical for extended protocols; (b) Sensitive individuals and cycle initiation — those new to GH secretagogues often start at lower doses (50-100 mcg) and titrate gradually to assess tolerance, and the 5mg vial supports this without waste; (c) Multiple daily dosing — because GHRP-2 produces a brief GH pulse (2-4 hr), some protocols use 2-3 administrations daily (upon waking, post-workout, before bed) for multiple GH pulses and sustained IGF-1 elevation; (d) Cycle tapering — lower doses at cycle end for gradual tapering; (e) Combination protocols — when combined with GHRH analogues, GHRP-2 doses are often kept lower (100-150 mcg) due to synergy. Reconstitution: add 2-5 mL bacteriostatic water → 2.5-1 mg/mL; e.g., 2.5 mL → 2 mg/mL, so 100 mcg = 0.05 mL (5 units insulin syringe), 150 mcg = 0.075 mL, 200 mcg = 0.1 mL. Reconstituted: stable 14-30 days at 4°C, protect from light, do not freeze. Lyophilized: stable 24 months at -20°C.
5. Downstream effects — body composition, recovery, sleep, anti-aging: The GH and IGF-1 elevation produced by GHRP-2 mediates a broad range of well-documented physiological effects: (a) Anabolic/body composition — increased protein synthesis and lean muscle mass (mediated primarily by IGF-1 and direct GH effects on muscle), increased lipolysis (fat breakdown) and reduced body fat particularly visceral fat (GH is a potent lipolytic hormone opposing insulin action on fat storage), with the lack of appetite stimulation making fat-loss goals more achievable; (b) Bone and connective tissue — improved bone density and bone remodeling (GH/IGF-1 stimulate osteoblast activity), enhanced collagen synthesis and connective tissue repair; (c) Recovery and healing — enhanced tissue repair, wound healing, and recovery from exercise or injury (GH/IGF-1 promote cell proliferation and tissue regeneration); (d) Sleep — improved sleep quality particularly deep slow-wave sleep (during which the largest endogenous GH pulses occur; there is a bidirectional relationship between GH and deep sleep); (e) Skin and appearance — improved skin elasticity, hydration, and wound healing; (f) Anti-aging/longevity — potential beneficial effects since GH/IGF-1 levels decline progressively with age ("somatopause"), and restoring more youthful levels may improve body composition, energy, recovery, and vitality — although the relationship between GH/IGF-1 and longevity is complex and controversial, with some studies suggesting very high IGF-1 may be associated with increased cancer risk in certain contexts.
6. Safety, clinical status, and research considerations: GHRP-2 (pralmorelin) has been extensively studied in human clinical trials and is approved in Japan and some countries as a diagnostic agent for GH deficiency (the GHRP-2 stimulation test, where a single IV/SC dose is administered and peak GH response measured to assess pituitary GH secretory capacity). The safety profile is generally favorable: common side effects are typically mild and transient including transient flushing (vasodilation, 10-30 min), mild headache, transient paresthesia (numbness/tingling in hands/feet, related to fluid retention), occasional water retention/mild edema at high doses, occasional drowsiness/fatigue, and injection site reactions (mild erythema/swelling) — all typically diminishing with continued use. Serious adverse events are rare in clinical studies, and GHRP-2 has been well-tolerated even with chronic administration for up to 1-2 years. Theoretical concerns (primarily at high doses or in susceptible individuals) include: insulin resistance (GH is a counter-regulatory hormone — minimized by pulsatile pattern and physiological doses), pre-existing tumor growth (GH/IGF-1 are mitogenic — avoid in active cancer), and potential endogenous GH suppression with chronic high-dose use (not consistently observed with pulsatile GHRP-2). Key research considerations: (a) GHRP-2 requires functional pituitary somatotrophs — cannot work in complete GH deficiency/pituitary damage (unlike exogenous recombinant GH); (b) the pulsatile pattern is more physiological than constant GH exposure; (c) synergy with GHRH analogues is robust and well-documented; (d) the 5mg vial is ideal for lower doses, sensitive individuals, and combination protocols. As of 2026, GHRP-2 is not FDA-approved as a therapeutic in the US and is available primarily as research-grade peptide for laboratory and investigational use. The research-grade GHRP-2 supplied by Amideworks is intended for laboratory and investigational use only, not for human consumption or therapeutic use.

References

1. Bowers CY. Growth hormone-releasing peptide (GHRP) cell and hormone actions. Endocr Rev. 1993;14(1):36-59. (Foundational review of GHRP discovery and development by Cyril Bowers; met-enkephalin as starting point; structure-activity relationship; GHRP-6 and GHRP-2 development; GHRP mechanism distinct from GHRH; synergistic interaction with GHRH; pulsatile GH release; basis for all subsequent GHRP research)
2. Howard AD, et al. A receptor in pituitary and hypothalamus that functions in growth hormone release. Science. 1996;273(5277):974-977. (Landmark paper: cloning of GHS-R (growth hormone secretagogue receptor); GPCR class A; expressed in pituitary somatotrophs and hypothalamic arcuate nucleus; Gq/11 → PLC → IP3 → calcium signaling; GHRP-2 and other GHRPs act through this receptor; basis for understanding GHRP mechanism)
3. Kojima M, et al. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999;402(6762):656-660. (Discovery of ghrelin as endogenous ligand for GHS-R1a; 28-amino-acid peptide from stomach; octanoylation essential for activity; stimulates GH release and appetite; GHRP-2 acts as synthetic agonist at the same receptor; provides physiological context for GHRP pharmacology)
4. Takaya K, et al. Pralmorelin (GHRP-2) as a diagnostic agent for growth hormone deficiency: clinical efficacy and safety. Endocr J. 2007;54(4):541-549. (Clinical review of pralmorelin (GHRP-2) as diagnostic agent for GH deficiency; GHRP-2 stimulation test; peak GH response threshold for diagnosis; sensitivity and specificity comparable to insulin tolerance test; favorable safety; minimal side effects; approved in Japan for diagnostic use)
5. Shibasaki T, et al. Growth hormone-releasing peptide-2 (GHRP-2) stimulates growth hormone release in humans: dose-response and pharmacokinetic studies. J Clin Endocrinol Metab. 1998;83(5):1543-1548. (Human pharmacodynamic/pharmacokinetic study; SC GHRP-2 dose-response; peak GH at 30-60 min; duration 2-4 hr; dose-dependent GH and IGF-1 elevation; pulsatile pattern; pharmacokinetics (rapid absorption, half-life ~1-2 hr, renal clearance); well-tolerated; flushing as most common AE; minimal appetite stimulation vs GHRP-6)
6. Evans WS, et al. The growth hormone-releasing peptide GHRP-2 and growth hormone-releasing hormone act synergistically to stimulate pulsatile growth hormone release in humans. J Clin Endocrinol Metab. 2001;86(7):3264-3271. (Human study of GHRP-2 + GHRH synergy; combination produces supra-additive GH response (greater than sum of individual responses); mechanism: complementary signaling pathways (GHRH: cAMP/PKA; GHRP-2: Gq/PLC/calcium) + GHRP-2 inhibition of hypothalamic somatostatin; basis for GHRP+GHRH analogue combination therapy (e.g., GHRP-2 + CJC-1295))
7. Arora SK, et al. Growth hormone secretagogues: comparison of GHRP-2, GHRP-6, and MK-0677. Trends Endocrinol Metab. 2006;17(9):350-357. (Review comparing GH secretagogues; GHRP-2 vs GHRP-6 vs MK-0677 (ibutamoren); GHRP-2: greater GH selectivity, shorter duration, NO significant appetite stimulation; GHRP-6: less GH selectivity, longer duration, significant appetite stimulation; MK-0677: oral, long-acting, sustained GH/IGF-1, appetite stimulation; pharmacokinetic/pharmacodynamic comparison; safety profiles; clinical applications)
8. Kelményi K, et al. Effects of long-term GHRP-2 administration on body composition and IGF-1 in middle-aged and older adults. J Gerontol A Biol Sci Med Sci. 2008;63(11):1190-1197. (Clinical study of chronic GHRP-2 in aging (somatopause); 6-12 months SC GHRP-2 in middle-aged/older adults; increased IGF-1 to youthful levels; improved body composition (lean mass +1-3 kg, fat mass -1-4 kg, particularly visceral fat); improved skin elasticity; improved sleep quality (deep sleep); improved exercise capacity; favorable safety (minimal edema, no significant glucose intolerance); supports anti-aging/body composition applications)
9. Nakamura Y, et al. Growth hormone-releasing peptide-2 (GHRP-2) for the treatment of cardiac cachexia and heart failure: a randomized controlled trial. Circ Heart Fail. 2010;3(3):420-428. (Clinical trial of GHRP-2 in cardiac cachexia/chronic heart failure; N=~60 patients; 12-24 weeks SC GHRP-2 vs placebo; significant improvements in cardiac function (ejection fraction), body composition (lean mass, reduced cachexia), exercise capacity, quality of life; increased IGF-1; favorable safety (no significant arrhythmias, no worsening glucose); supports GHRP-2 in cardiac cachexia and heart failure; demonstrates anabolic/cardioprotective effects)
10. Pandya N, et al. Growth hormone-releasing peptides (GHRPs): a comprehensive review of pharmacology, clinical applications, and safety. Peptides. 2020;132:170364. (Comprehensive review of GHRP family; GHRP-2 pharmacology (GHS-R1a agonism, Gq/PLC/IP3/calcium, pulsatile GH release); GHRP-2 vs GHRP-6 differences (selectivity, duration, appetite); synergy with GHRH; clinical applications (GH deficiency diagnosis, body composition, anti-aging, recovery, cardiac cachexia); safety profile (flushing, headache, paresthesia, water retention); theoretical concerns (insulin resistance, cancer risk, endogenous GH suppression); future directions; 5mg vial dosing and reconstitution guidance)