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Free U.S. shipping on orders over $150Native GHK-Cu peptide is released from the extracellular matrix, cleaved from its parent protein, SPARC (secreted protein, acidic, and rich in cysteine), during extracellular matrix remodelling. Studies find it has vital roles in copper transport, tissue repair, inflammation modulation, and gene regulation [1].
A tripeptide, GHK-Cu is composed of glycine (Gly), histidine (His), and lysine (Lys) [1]. This amino acid complex binds tightly to copper, forming a stable coordination complex [2]. This binding capacity is what gives GHK-Cu its unique biological signalling and regenerative properties [2]. After performing its functions, GHK-Cu is degraded by serum peptidases. Studies show that circulating levels decrease with age, averaging 200 ng/mL at age twenty and declining to 80 ng/mL by age sixty, potentially impacting regenerative capacity [1].
Copper(II) is a redox-active metal required as a cofactor for many enzymes, including cytochrome C oxidase, lysyl oxidase, and superoxide dismutase [2]. GHK binds copper in a bioavailable, non-toxic form, supports shuttling it into cells, and maintains intracellular copper homeostasis [2].
GHK-Cu shows abilities to up- or downregulate over 4,000 genes. These pathways are many, and include those involved in tissue regeneration and repair, anti-inflammatory signalling, antioxidant defenses, and cell growth and differentiation [2].
While scientists are still elucidating some of GHK-Cu peptide’s mechanisms, current research suggests that they include augmenting transcription factors, epigenetic modification (particularly histone and chromatin) and oxidative stress signalling [2].
Research is still emerging on the wide applications of GHK-Cu peptide; however, our current understanding of its actions point towards applications particularly in skin and hair, and regenerative processes.
Research suggests that GHK-Cu peptide may have roles in reprogramming older tissues to act more youthful [2]. When skin gets injured, GHK-Cu is naturally released, acting as an emergency signal to activate skin healing processes [3].
A study using a test tube wound model found that GHK-Cu increases the production of collagen (which gives skin structure), elastin (which keeps skin elastic), and decorin and glycosaminoglycans (key molecules that hydrate and organize skin tissue) [4].
GHK-Cu also supports the balance of enzymes that break down skin proteins, MMPs, and their inhibitors, TIMPs [5],[6]. This prevents the buildup of damaged proteins, and overactive breakdown, which can lead to thinning and sagging skin [2].
One cell-based study found that skin cells exposed to GHK-Cu in combination with red LED light had 12.5x greater cell survival, 230% increase in fibroblast growth factor, and 70% higher collagen production [7].
At the stem cell level, GHK-Cu improved the health and shape of basal cells in the epidermis, increasing markers of stemness, which may help skin regenerate better with age [8].
GHK-Cu peptides show benefits for supporting hair growth, by [9]:
Studies find that GHK-Cu can stimulate fibroblasts, a particular type of skin cell, to produce VEGF (vascular endothelial growth factor), which helps support the growth of new blood vessels surrounding the hair follicle [9]. More blood vessels allow for greater nutrient and oxygen delivery to the area, thus supporting stronger, faster growing hair [9].
It also reduces the production of TGF-beta, a chemical that signals to hair follicles to stop growing and enter the shedding phase of hair growth [9]. With less TGF-beta, hair remains in the growth phase for longer.
By encouraging dermal papilla cells to multiply and protecting them from apoptosis, GHK-Cu supports the development and growth of new hair, by keeping follicles healthy [9].
While more research is needed, our understanding of GHK-Cu points towards potential applications of this peptide in wound healing and repair processes, promotion of antioxidant defenses, angiogenesis, gene modulation, and more [2].
Research Use Only. All findings described above are derived from preclinical studies (animal models and in vitro experiments). GHK-Cu is not approved by the FDA for any diagnostic or therapeutic use in humans. Genesis Peptides makes no claims regarding human clinical efficacy. This product is sold exclusively for laboratory research.
Every lot undergoes six independent assays before release. Results are published in the lot-specific Certificate of Analysis.
Every lot undergoes our 6-panel testing protocol: identification by ESI-MS, purification by RP-HPLC, conformity, sterility screening, quantification of net peptide content, and LAL endotoxin screening. Full analytical data is published in the Certificate of Analysis for each lot.
Lyophilized peptides should be stored at -20°C or below for long-term stability. Once reconstituted, peptides should be stored at 2–8°C and used within a reasonable timeframe depending on the specific compound. Avoid repeated freeze-thaw cycles. Always store in a dry environment away from direct light.
Orders are processed within 1–3 business days after payment confirmation. Orders placed after 3:00 PM Pacific time or on weekends and holidays will begin processing the next business day. We offer free standard shipping on orders over $150. All orders are shipped in insulated packaging with ice packs when necessary. Standard delivery typically takes 2–4 business days within the continental US.
No. All compounds sold by Genesis Peptides are strictly for in vitro and preclinical laboratory research purposes only. They are not approved for human consumption, therapeutic use, or diagnostic purposes. By purchasing, you confirm the products will be used solely for legitimate research applications.
A Certificate of Analysis (COA) is a document issued by our analytical laboratory that reports the results of all quality control tests performed on a specific lot of product. Each COA includes HPLC chromatograms, mass spectra, endotoxin results, and quantification data where applicable. COAs are available in our COA Library for every lot we have shipped.
Yes. We offer volume pricing for universities, research institutions, and laboratories with recurring needs. Discounts begin at 100+ units and scale with volume. Contact our team for a custom quote tailored to your research requirements.
FOR RESEARCH USE ONLY — Products are sold exclusively for in vitro and preclinical laboratory research. Not for human consumption or administration. Not intended for diagnostic or therapeutic use. These statements have not been evaluated by the FDA.
GHK-Cu + TB-500 + BPC-157 + KPV is a Made-in-USA research blend (GHK-Cu 50mg + TB-500 (Thymosin Beta-4) 10mg + BPC-157 10mg + KPV 10mg), synthesized and finished in U.S. facilities and tested to the same analytical standard as the rest of the catalog. For research use only — not for human consumption. GHK-Cu What is GHK-Cu? Native GHK-Cu peptide is released from the extracellular matrix, cleaved from its parent protein, SPARC (secreted protein, acidic, and rich in cysteine), during extracellular matrix remodelling. Studies find it has vital roles in copper transport, tissue repair, inflammation modulation, and gene regulation [1]. A tripeptide, GHK-Cu is composed of glycine (Gly), histidine (His), and lysine (Lys) [1]. This amino acid complex binds tightly to copper, forming a stable coordination complex [2]. This binding capacity is what gives GHK-Cu its unique biological signalling and regenerative properties [2]. After performing its functions, GHK-Cu is degraded by serum peptidases. Studies show that circulating levels decrease with age, averaging 200 ng/mL at age twenty and declining to 80 ng/mL by age sixty, potentially impacting regenerative capacity [1]. Copper(II) is a redox-active metal required as a cofactor for many enzymes, including cytochrome C oxidase, lysyl oxidase, and superoxide dismutase [2]. GHK binds copper in a bioavailable, non-toxic form, supports shuttling it into cells, and maintains intracellular copper homeostasis [2]. GHK-Cu shows abilities to up- or downregulate over 4,000 genes. These pathways are many, and include those involved in tissue regeneration and repair, anti-inflammatory signalling, antioxidant defenses, and cell growth and differentiation [2]. While scientists are still elucidating some of GHK-Cu peptide’s mechanisms, current research suggests that they include augmenting transcription factors, epigenetic modification (particularly histone and chromatin) and oxidative stress signalling [2]. What does GHK-Cu do? The research Research is still emerging on the wide applications of GHK-Cu peptide; however, our current understanding of its actions point towards applications particularly in skin and hair, and regenerative processes. GHK-Cu and skin Research suggests that GHK-Cu peptide may have roles in reprogramming older tissues to act more youthful [2]. When skin gets injured, GHK-Cu is naturally released, acting as an emergency signal to activate skin healing processes [3]. A study using a test tube wound model found that GHK-Cu increases the production of collagen (which gives skin structure), elastin (which keeps skin elastic), and decorin and glycosaminoglycans (key molecules that hydrate and organize skin tissue) [4]. GHK-Cu also supports the balance of enzymes that break down skin proteins, MMPs, and their inhibitors, TIMPs [5],[6]. This prevents the buildup of damaged proteins, and overactive breakdown, which can lead to thinning and sagging skin [2]. One cell-based study found that skin cells exposed to GHK-Cu in combination with red LED light had 12.5x greater cell survival, 230% increase in fibroblast growth factor, and 70% higher collagen production [7]. At the stem cell level, GHK-Cu improved the health and shape of basal cells in the epidermis, increasing markers of stemness, which may help skin regenerate better with age [8]. GHK-Cu and hair GHK-Cu peptides show benefits for supporting hair growth, by [9]: Improving blood flow to hair follicles Preventing hair shedding and premature hair loss Stimulating the growth of new hair follicles Studies find that GHK-Cu can stimulate fibroblasts, a particular type of skin cell, to produce VEGF (vascular endothelial growth factor), which helps support the growth of new blood vessels surrounding the hair follicle [9]. More blood vessels allow for greater nutrient and oxygen delivery to the area, thus supporting stronger, faster growing hair [9]. It also reduces the production of TGF-beta, a chemical that signals to hair follicles to stop growing and enter the shedding phase of hair growth [9]. With less TGF-beta, hair remains in the growth phase for longer. By encouraging dermal papilla cells to multiply and protecting them from apoptosis, GHK-Cu supports the development and growth of new hair, by keeping follicles healthy [9]. Other regenerative processes While more research is needed, our understanding of GHK-Cu points towards potential applications of this peptide in wound healing and repair processes, promotion of antioxidant defenses, angiogenesis, gene modulation, and more [2]. TB-500 (Thymosin Beta-4) What is TB500 (Thymosin Beta 4)? TB500 peptide is a shorter, bioactive fragment of thymosin beta-4, designed to focus on thymosin beta-4’s most therapeutically relevant region, the 7-amino acid sequence LKKTETQ responsible for actin binding and tissue regeneration [1]. Though structurally simpler than the full-length thymosin beta-4, TB500 peptide retains potent biological activity [5]. The number 500 in TB500 is added as a commercial name, without biological or scientific significance. Key biochemical features include: Actin-binding domain [6]: Essential for cytoskeletal regulation, enabling cell migration and tissue remodelling. Essential amino acid residues [6]: Support actin polymerization and cellular mobility. No post-transitional modifications [6]: As a synthetic peptide, TB500 lacks glycosylation or phosphorylation, ensuring structural stability. What does TB500 do? TB500 exerts multi-system effects, supporting wound healing, reducing inflammation, promoting cell regeneration, and enhancing immune defenses [1]. Tissue repair and regeneration TB500 accelerates tissue repair by binding actin, a key structural protein in cells. This interaction stimulates stem cell recruitment and differentiation at injury sites, migration of skin cells to close wounds faster, and formation of new blood vessels (angiogenesis) to improve oxygen and nutrient delivery [1]. It also enhances collagen alignment and increases laminin-5, both essential for strong and well-structured tissues [7]. Simultaneously, it reduces the number of scar-forming cells, minimizing fibrotic tissue formation [8]. Animal studies have confirmed TB500 peptide’s ability to reduce tissue damage, speed up recovery, and promote healing even in challenging conditions [9]. Human trials suggest that topical formulations are safe and effective in wound repair. Emerging data also support the potential role of TB500 in neurological and cardiac tissue regeneration, aiding recovery after events like stroke or heart attack [9]. Anti-inflammatory and immunomodulatory effects Following tissue injury, high levels of inflammation can damage tissues and lead to permanent scarring. TB500 peptide mitigates this response, lowering the levels of inflammatory cells and the chemical signals they release [1]. This has downstream impacts of reducing tissue swelling, protecting healthy tissue, and creating an environment supportive of proper healing with less scar tissue formation [1]. A key anti-inflammatory mechanism involves the NF-kB signalling pathway, which controls the expression of many pro-inflammatory genes. TB500 inhibits NF-kB activation, prevents p65 subunit phosphorylation, and blocks nuclear translocation of NF-kB [10]. These actions have been demonstrated in corneal, cardiac, and liver tissues. The NF-kB inhibition contributes to reduced inflammation and improved healing responses in these tissues [10]. TB500 peptide modulates the toll-like receptor-4 (TLR-4) pathway, which is central to innate immune responses [11]. Through upregulation of microRNA-146a, TB500 can suppress this pathway, promoting anti-inflammatory effects [11]. For this reason, TB500 may indirectly support the repair of gut barriers by improving the proliferation and migration of cells, and supporting tissue healing processes. Furthermore, a peptide fragment within TB500, Ac-SDKP, has been shown to reduce fibrosis (e.g., heart scarring after myocardial infarction), likely through similar anti-inflammatory and anti-proliferative mechanisms [6]. Antibacterial and antiviral effects TB500 strengthens antimicrobial defenses by increasing the expression of antimicrobial peptides (AMPs) such as keratin 6A, CAMP, beta-defensins (BD2, BD3), and S100A8 [12]. These peptides help prevent bacterial adherence and enhance immune clearance of pathogens [12]. TB500 also boosts TLR4 expression, enhancing the recognition of bacterial invaders like LPS-producing pathogens [12]. When combined with antibiotics, TB500 enhances the activity of 12-LOX and 15-LOX enzymes, which promote resolution of inflammation and tissue restoration [12]. This synergy highlights TB500’s potential as an adjunct to antimicrobial therapies—supporting not only microbial defense but also repair of infected tissues. BPC-157 What is BPC-157? BPC-157 is a synthetic pentadecapeptide composed of 15 amino acids, with the sequence Gly-Glu-Pro-Pro-Pro-Gly-Lys-Pro-Ala-Asp-Asp-Ala-Gly-Leu-Val. It is a portion of a protein that occurs naturally in human gastric juice, commonly referred to as Body Protection Compound (BPC). Native BPC helps maintain gastrointestinal integrity under normal physiological conditions. BPC-157 is stable and soluble in water. As a synthetic peptide, BPC-157 is not produced endogenously in this exact form but is designed to replicate a biologically active fragment of the parent protein found in gastric secretions [1]. The peptide has been the subject of extensive preclinical research, particularly in the context of cellular proliferation, angiogenesis, and tissue repair mechanisms. BPC-157 has been studied in animal and in vitro models as a tool for investigating pathways associated with: Gastrointestinal homeostasis Vascular modulation Cytoprotection Inflammation modulation All research involving BPC-157 remains within the domain of experimental studies, and it is not approved for human therapeutic use. What does BPC-157 do? The research Inflammation and pain modulation BPC-157 has been extensively studied in preclinical models for its modulatory effects on inflammation, particularly in relation to tissue injury and repair processes [1]. In various rodent studies, administration of BPC-157 reduced markers of inflammation in models of gastrointestinal, musculoskeletal, and neural injury. By modulating inflammation, rat studies suggest that various BPC variants modulate pain, while BPC-157 predominantly reduces acute pain in incisional and formalin-induced pain [2]. In a rat model of allodynia, it also reduced pain by protecting nerve integrity from capsaicin [3]. BPC may also modulate the nitric oxide (NO) system. It counteracts both excessive and deficient NO activity, supporting endothelial integrity and attenuating leukocyte infiltration in inflamed tissues. This dual regulation may contribute to its observed ability to balance pro-inflammatory and anti-inflammatory signaling cascades [4]. In experimental colitis models, for example, BPC-157 administration was associated with: Reduced mucosal damage Decreased myeloperoxidase activity (a marker of neutrophil infiltration) Normalization of cytokine profiles BPC-157 also promotes angiogenesis (blood vessel growth) and stabilizes vascular function at sites of injury. This angiogenic support not only facilitates tissue repair but may also limit secondary inflammation resulting from ischemia and oxidative stress [5]. Research in tendon and ligament injury models similarly highlights reductions in edema and inflammatory cell presence following BPC-157 exposure. These findings are derived from animal studies, and while promising, they await confirmation in human clinical research to fully understand its therapeutic relevance. Tissue healing and stem cells BPC-157 can facilitate regeneration across various tissue types, including: Tendon Muscle Ligament Bone Nerve A key feature identified in these models is BPC-157’s capacity to modulate cellular and immune environments in ways that promote structural integrity and restoration of injured sites. In rat models of tendon fibroblasts, BPC-157 significantly upregulated growth hormone receptor expression, and enhanced the responsiveness of these cells to endogenous growth hormone [6]. This interaction promotes cell proliferation and tissue regeneration, increasing expression of proliferation markers: Proliferating cell nuclear antigen (PCNA) JAK2 signaling pathway These results suggest a supportive role in tendon repair processes at the molecular level, enhancing the body's natural regenerative mechanisms. BPC-157 may influence stem cell activity indirectly by optimizing the local microenvironment of injured tissues. While direct stimulation of stem cell differentiation by BPC-157 has not been definitively proven, its actions on surrounding tissues, blood vessels, and extracellular matrix components are believed to indirectly enhance stem cell-mediated repair processes. Gut health BPC-157 has been extensively studied in preclinical models for its protective and regenerative effects on the gastrointestinal (GI) tract [7]. Research in rat models of ileoileal anastomosis healing, for instance, shows that BPC-157: Modulates local immune responses Enhances granulation tissue formation Increases collagen and reticulin deposition Promotes re-epithelialization Supports the regeneration of muscular tissue strands at anastomotic sites. BPC-157 reduced adhesion formation and necrosis, while accelerating the resolution of edema and inflammatory infiltrates in treated animals compared to controls. Additional experimental models of intestinal injury, including those involving perforations, fistulas, or induced colitis, report that BPC-157 administration supported gut integrity by: Promoting angiogenesis Mitigating tissue necrosis Stabilizing microvascular structures The peptide’s influence on nitric oxide pathways and its modulation of endothelial function are proposed mechanisms underlying these benefits. While clinical trials in humans remain limited, the consistent findings across animal models offer a compelling basis for future investigation into its application in gut health contexts. BPC-157 in bees Bees are crucial pollinators whose populations are in significant declines. Research suggests that BPC-157 may help to improve bee health and survival. In bees, BPC-157 improves colony strength and enhances certain aspects of immune responses [8]. Supplementation of bee diets with the peptide reduced the infection load of the Nosema ceranae, a one-celled fungal parasite. BPC-157 also attenuates gut damage from N. ceranae infections [8]. Overall, BPC-157 may be beneficial in beekeeping. KPV What Is KPV Peptide? KPV is a short bioactive peptide composed of three amino acids: lysine (K), proline (P), and valine (V) [1]. It is derived from the larger parent molecule α-melanocyte-stimulating hormone (α-MSH), a peptide hormone that modulates inflammation, pigmentation, circadian rhythm, and immune responses [1]. Unlike the full α-MSH sequence, KPV represents the minimal active fragment capable of exerting anti-inflammatory and protective effects in experimental settings. Because of its small size, KPV is more stable and potentially more amenable to topical or localized delivery compared to its larger parent peptide [2]. KPV is a promising subject of investigation in areas where inflammation and tissue degeneration play central roles, including aging-related disorders. KPV Peptide Mechanism of Action KPV is thought to act through interactions with the melanocortin 1 receptor (MC1R), a G-protein-coupled receptor expressed in a variety of tissues, including skin, intestinal epithelial cells, and immune cells [3]. Anti-Inflammatory Activity One of the most consistent findings across KPV research is its anti-inflammatory activity, particularly in epithelial tissues such as the gut and skin. In preclinical studies, KPV downregulates pro-inflammatory cytokines, including: Tumor necrosis factor-α (TNF-α) [4, 5] Interleukin-1β (IL-1β) [6] Interleukin-6 (IL-6) [4] At the same time, KPV enhanced anti-inflammatory mediators, helping to restore immune balance in tissues that were chronically stressed or damaged. Wound Healing Wound healing is a complex process that requires coordinated activity between keratinocytes, fibroblasts, immune cells, and vascular networks [7]. With aging, this regenerative capacity declines, delaying healing and increasing the risk of chronic wounds and scarring. Research on KPV suggests that it may play a role in supporting tissue repair by modulating inflammation and stimulating cellular regeneration [8]. Animal studies indicate that KPV significantly accelerates keratinocyte migration and proliferation, which promote the re-epithelialization of damaged skin and cornea [9]. By dampening the inflammatory cascade, KPV creates a more favorable environment for tissue recovery [1]. In parallel, KPV has been shown to influence fibroblast activity and extracellular matrix remodeling, processes that underpin scar formation, collagen deposition, and the restoration of skin integrity [10]. In mouse models, KPV accelerates full-thickness wound closure and reduces scarring compared to untreated controls [11]. KPV accomplishes this through increased angiogenesis and collagen deposition. The peptide appears to limit oxidative and inflammatory injury and enhance reparative signaling, striking a balance between protecting cells from further damage and promoting regeneration. KPV Peptide Benefits and Side Effects Gut Barrier Protection In the gut, inflammation disrupts epithelial barrier integrity, leading to increased permeability and impaired nutrient absorption [12]. KPV may counteract this by supporting epithelial repair and reducing inflammatory signaling via inhibiting NF-𝛋B and MAPK signaling pathways [4]. In murine models of inflammatory bowel disease, KPV led to significantly earlier recovery and stronger regain of body weight. The peptide preserved epithelial integrity, reduced oxidative injury, and supported mucosal repair [13]. Skin Health and Repair In dermatological research, KPV has demonstrated the ability to: Reduce swelling Accelerate wound closure Promote keratinocyte migration Promote fibroblast activity In animal models of dermatitis and wound healing, KPV has demonstrated the ability to reduce redness, irritation, and swelling [14]. By balancing cytokine activity and oxidative stress, KPV may treat inflammatory skin conditions and restore healthy skin. KPV may also be particularly relevant to skin aging, where low-level chronic inflammation accelerates collagen degradation, barrier dysfunction, and visible changes [15]. These effects are consistent with its origin as a fragment of α-MSH, a peptide historically studied for its skin-protective properties. Safety/Side Effect Profile KPV is generally well tolerated in experimental settings [16]. Unlike full-length α-MSH or other melanocortin peptides, KPV does not significantly influence pigmentation, reducing the risk of unwanted skin-darkening effects. Preclinical studies report no major systemic toxicity or adverse events, and topical or localized administration appears safe. Although extremely rare, applications of proteins or peptides may run the risk of local irritation or allergic reactions [17]. The evidence base remains limited, with most data derived from animal models, in vitro experiments, or small pilot human studies. Long-term safety, optimal dosing, and potential interactions of KPV with other compounds have yet to be fully established.
Snapshot GHRP-2 is a growth hormone–releasing peptide studied for its ability to stimulate endogenous GH and downstream IGF-1 signaling. By engaging the GHS-R1a receptor and CD36-associated pathways such as PI3K-AKT, it influences tissue protection, inflammatory balance, pain modulation, and body composition through coordinated endocrine and cellular signaling. What is GHRP-2 and its mechanism of action? Growth Hormone–Releasing Peptide-2 (GHRP-2) is a synthetic hexapeptide designed to stimulate the endogenous release of growth hormone (GH). GHRP-2 activates GHS-R1a, a receptor expressed in both the pituitary gland and hypothalamus [1]. GHS-R1a increases GH secretion, which then stimulates hepatic and peripheral production of insulin-like growth factor-1 (IGF-1), a key mediator of GH’s effects on tissue growth, tissue repair, and metabolic regulation. In addition to its role in GH release, GHRP-2 interacts with membrane glycoprotein CD36, which activates downstream pathways such as PI3K-AKT to help with cell survival, nutrient signaling, and anabolic processes [2]. While the functional relevance of these non-GHS-R pathways continues to be explored, they suggest that GHRP-2 may influence cellular metabolism beyond GH secretion alone. GHRP-2 benefits Tissue protection GHRP-2 has been studied for its role in tissue-protective signaling, an effect that appears to arise from activating intracellular survival pathways. A study investigated whether GHRP-2 could protect against glucocorticoid-induced muscle atrophy both in whole rats and muscle cell models [3]. Researchers found that dexamethasone significantly increased expression of the muscle-specific ubiquitin ligases Atrogin-1 and MuRF1, drivers of muscle protein breakdown. Treatment with GHRP-2 resulted in: Dose-dependent reduction of Atrogin-1 and MuRF1 levels. No increase in circulating or local IGF-1 levels, indicating its protective effect was independent of the GH–IGF-1 axis. These results support GHRP-2’s potential role in muscle preservation during catabolic states, such as steroid exposure, chronic illness, or disuse. Anti-inflammation and immunomodulation GHRP-2 may influence inflammatory signaling and immune modulation through both endocrine and intracellular pathways. An animal study examined the effects of GHRP-2 on inflammation, metabolic disruption, and cachexia in a rat model of chronic inflammatory arthritis [4]. Arthritis and inflammation was induced in male Wistar rats using Freund’s adjuvant, followed by daily administration of GHRP-2 or saline for eight days. Arthritis induction was associated with: Elevated circulating ghrelin and reduced leptin levels (p < 0.01) Increased circulating IL-6 and nitric oxide metabolites (p < 0.01) Despite not increasing food intake in arthritic animals, GRHP-2 administration resulted in: Increased circulating leptin concentrations (p < 0.01) Reduced arthritis scores and paw swelling (p < 0.01) Suppression of endotoxin-induced IL-6 production and nitric oxide release in cultured peritoneal macrophages These results suggest that GHRP-2’s benefits were not just driven by appetite stimulation. Analgesia GHRP-2 can influence pain modulation, an effect thought to arise from its interaction with growth hormone signaling as well as central opioid pathways. An animal study investigated the role of GHRP-2 in central pain modulation using a mouse model of acute pain [5]. Researchers increased doses of GHRP-2 via intracerebroventricular (i.c.v.) administration (0.1, 0.3, 1, 3, and 10 nmol/L) and measured pain through the tail immersion test. Results showed: GHRP-2 exhibited a dose and time-dependent antinociceptive effect. Analgesic response was completely blocked by a GHS-R1α antagonist. Analgesic effect was also dependent on the δ- and κ-opioid receptors; receptor blockade significantly reduced effects. Analgesic effects were unchanged by μ-opioid receptor blockade, and enhanced with morphine. Results indicate GHRP-2 modulates pain perception through central ghrelin receptor activation and opioid receptor crosstalk, supporting its value as a pain regulation adjunct. Body composition and muscle mass GHRP-2 can influence body composition through IGF-1. A case study examined the effects of long-term GHRP-2 administration in a patient with a 20-year history of anorexia nervosa [6]. Although the patient’s fear of eating and desire to be thin had improved, persistent gastrointestinal dysfunction (vomiting, constipation, hypoglycemia, and sub-ileus) prevented meaningful increases in food intake or body weight. GHRP-2 was administered intranasally before each meal for one year. Following treatment initiation, the patient experienced: Symptomatic Improvement Increased hunger Reduced early satiety Greater food intake Clinical Improvements Improved hypoglycemia 6.7kg increase in body weight Improvements in fatigability and muscle strength No significant adverse effects were recorded, presenting a new approach to managing treatment-resistant anorexia nervosa through GHRP-2 signaling. Future studies will need to analyze greater sample sizes for reproducibility. References 1 Laferrère, B., Abraham, C., Russell, C. D. and Bowers, C. Y. (2005) Growth hormone releasing peptide-2 (GHRP-2), like ghrelin, increases food intake in healthy men. J. Clin. Endocrinol. Metab., The Endocrine Society 90, 611–614 2 Demers, A., McNicoll, N., Febbraio, M., Servant, M., Marleau, S., Silverstein, R., et al. (2004) Identification of the growth hormone-releasing peptide binding site in CD36: a photoaffinity cross-linking study. Biochem. J., Portland Press Ltd. 382, 417–424 3 Yamamoto, D., Ikeshita, N., Matsubara, T., Tasaki, H., Herningtyas, E. H., Toda, K., et al. (2008) GHRP-2, a GHS-R agonist, directly acts on myocytes to attenuate the dexamethasone-induced expressions of muscle-specific ubiquitin ligases, Atrogin-1 and MuRF1. Life Sci., Elsevier BV 82, 460–466 4 Granado, M., Priego, T., Martín, A. I., Villanúa, M. A. and López-Calderón, A. (2005) Anti-inflammatory effect of the ghrelin agonist growth hormone-releasing peptide-2 (GHRP-2) in arthritic rats. Am. J. Physiol. Endocrinol. Metab., American Physiological Society 288, E486–92 5 Zeng, P., Li, S., Zheng, Y.-H., Liu, F.-Y., Wang, J.-L., Zhang, D.-L., et al. (2014) Ghrelin receptor agonist, GHRP-2, produces antinociceptive effects at the supraspinal level via the opioid receptor in mice. Peptides, Elsevier BV 55, 103–109 6 Haruta, I., Fuku, Y., Kinoshita, K., Yoneda, K., Morinaga, A., Amitani, M., et al. (2015) One-year intranasal application of growth hormone releasing peptide-2 improves body weight and hypoglycemia in a severely emaciated anorexia nervosa patient: GHRP-2 treatment for anorexia nervosa. J. Cachexia Sarcopenia Muscle, Wiley 6, 237–241
Snapshot GHRP-6 is a ghrelin receptor agonist studied for its ability to stimulate endogenous growth hormone release and modulate appetite, energy balance, and neuroendocrine signaling. Through activation of GHS-R1a and downstream pathways such as GH/IGF-1 and prolactin, GHRP-6 has been explored for effects on body composition, organ protection, immune regulation, and sleep physiology. GHRP-6 uniqueness and mechanisms of action Growth Hormone–Releasing Peptide-6 (GHRP-6) is a synthetic hexapeptide that promotes growth hormone (GH) release by activating hypothalamic and pituitary signaling pathways. What distinguishes GHRP-6 from other GHRPs is its orexigenic and neuroendocrine signaling [1]. GHRP-6 is a potent appetite-stimulating agent, reflecting strong activation of central ghrelin pathways involved in hunger perception and meal initiation. This characteristic has made it a valuable research tool for studying the neural integration of appetite, growth hormone dynamics, and metabolic signaling. At the receptor level, GHRP-6 activates GHS-R1a, triggering downstream GH/IGF-1 axis activity. Through this pathway, GHRP-6 indirectly influences: Anabolic signaling Tissue maintenance Metabolic coordination In experimental settings, GHRP-6 increases secretion of other pituitary hormones, including prolactin and cortisol, highlighting its broader impact on neuroendocrine regulation [2, 3]. GHRP-6 benefits Growth hormone and growth stimulation GHRP-6 can cause release of GH and downstream IGF-1 effects independent of GHRH or somatostatin. This occurs through activation of GHS-R1a [4]. Body composition and appetite GHRP-6 has unique effects on appetite regulation and body composition. An animal study investigated the effects of GHRP-6 on food intake, body weight, and fat accumulation. Researchers compared adrenal-intact with adrenalectomised (ADX) rats (no glucocorticoid secretion) [5]. Rats received twice-daily subcutaneous injections of GHRP-6 (250 μg/kg) for two weeks. Results showed: Significant increases in body weight in both groups, indicating that GHS-induced weight gain occurs independently of glucocorticoids. Increased fat mass (15-20% subcutaneous and visceral) in adrenal-intact rats only (p < 0.05). Weight gain without increases in fat or organ mass in ADX rats. Increased food intake for up to 7 hours in adrenal-intact and ADX rats (p < 0.05). GHRP-6–induced body weight gain is not dependent on glucocorticoids, but activation of the HPA axis contributes to fat mass accumulation. Organ protection and immunomodulation A study evaluated the effects of GHRP-6 on epithelial repair and organ protection in cell models of intestinal injury and rat models of multiple organ failure (MOF) induced by hepatic ischaemia–reperfusion [6]. In cells, GHRP-6 administration tripled cell migration compared with controls (p < 0.01). No increase in cell proliferation measured by [³H]-thymidine incorporation, indicating enhanced cellular motility rather than uncontrolled growth. In the in vivo MOF model, ischaemia–reperfusion caused substantial tissue injury, including: Fivefold increases in neutrophilic infiltration (myeloperoxidase activity) Fourfold increases in lipid peroxidation (malondialdehyde levels) Hepatic and intestinal histological damage In the rat MOF model, results showed that: Pre-treatment with GHRP-6 (120 μg/kg) significantly attenuated injury markers by 50–85% (p < 0.05). When combined with epidermal growth factor (1 mg/kg), additional protective effects were observed. Lung and renal injury markers were also reduced. GHRP-6 directly enhances epithelial repair through increased cell migration and provides broad organ-protective effects, supporting further investigation as a research strategy for mitigating inflammatory and ischemic organ injury. Sleep GHRP-6 has been studied for its influence on sleep architecture. A clinical study investigated how different routes of administration of GHRP-6 influence sleep architecture and endocrine hormone secretion in healthy young men [7]. Participants received either 300 μg/kg orally, 30 μg/kg intranasally, or 30 μg/kg sublingually at night. Results showed that: Oral administration No significant changes in GH, ACTH, or cortisol secretion Reduced stage 2 sleep during the second half of the night Sublingual administration Increased GH secretion during the first half of the night, with no significant effects on ACTH, cortisol, or sleep stages Intranasal administration Significant increase in GH levels across the entire night Increased ACTH secretion in the first half of the night Increased stage 2 sleep during the second half of the night Decreased delta power across the night Results indicate that GHRP-6 can modulate both endocrine secretion and sleep, but that intranasal delivery was the most effective in influencing nocturnal GH secretion and sleep-related parameters. References 1 Yahashi, S., Kang, K. S., Kaiya, H. and Matsuda, K. (2012) GHRP-6 mimics ghrelin-induced stimulation of food intake and suppression of locomotor activity in goldfish. Peptides, Elsevier BV 34, 324–328 2 Carmignac, D. F., Bennett, P. A. and Robinson, I. C. (1998) Effects of growth hormone secretagogues on prolactin release in anesthetized dwarf (dw/dw) rats. Endocrinology, The Endocrine Society 139, 3590–3596 3 Oliveira, J. H. A., Vieira, J. G. H., Abucham, J. and Lengyel, A. M. J. (2003) GHRP-6 is able to stimulate cortisol and ACTH release in patients with Cushing’s disease: comparison with DDAVP. J. Endocrinol. Invest., Springer Science and Business Media LLC 26, 230–235 4 Micic, D., Mallo, F., Peino, R., Cordido, F., Leal-Cerro, A., Garcia-Mayor, R. V., et al. (1993) Regulation of growth hormone secretion by the growth hormone releasing hexapeptide (GHRP-6). The Journal of pediatric endocrinology, J Pediatr Endocrinol 6 https://doi.org/10.1515/JPEM.1993.6.3-4.283 5 Tung, Y. L., Hewson, A. K. and Dickson, S. L. (2004) Glucocorticoid-dependent stimulation of adiposity and appetite by a ghrelin mimetic in the rat. Eur. J. Endocrinol., Oxford University Press (OUP) 150, 905–911 6 Cibrián, D., Ajamieh, H., Berlanga, J., León, O. S., Alba, J. S., Kim, M. J.-T., et al. (2006) Use of growth-hormone-releasing peptide-6 (GHRP-6) for the prevention of multiple organ failure. Clin. Sci. (Lond.), Portland Press Ltd. 110, 563–573 7 Frieboes, R. M., Murck, H., Antonijevic, I. A. and Steiger, A. (1999) Effects of growth hormone-releasing peptide-6 on the nocturnal secretion of GH, ACTH and cortisol and on the sleep EEG in man: role of routes of administration: Sleep endocrinology after GHRP-6. J. Neuroendocrinol., Wiley 11, 473–478