Ipamorelin

BACKGROUND: Postoperative ileus is a significant clinical challenge lacking effective management strategies. Ghrelin-receptor stimulation has promotility effects in the upper and lower gastrointestinal tract. OBJECTIVE: This proof-of-concept, phase 2, randomized study evaluated the safety and efficacy of the ghrelin-receptor agonist ipamorelin in the treatment of postoperative ileus following abdominal surgery (ClinicalTrials.gov NCT00672074). DESIGN: The design was a multicenter, double-blind, placebo-controlled, clinical trial. SETTINGS: The settings include hospital inpatients. PATIENTS: The patients were adults undergoing small and large bowel resection by open or laparoscopic surgery. INTERVENTION: The intervention was intravenous infusions of 0.03-mg/kg ipamorelin vs placebo twice daily, on postoperative day 1 to 7 or hospital discharge. MAIN OUTCOME MEASURES: Safety was assessed by monitoring adverse events and laboratory tests. The key efficacy endpoint was time from first dose of study drug to tolerance of a standardized solid meal. RESULTS: One hundred seventeen patients were enrolled, of whom 114 patients composed the safety and modified intent-to-treat populations. Demographic and disease characteristics were balanced between groups. Overall incidence of any treatment-emergent adverse events was 87.5 % in the ipamorelin group and 94.8 % in placebo group. Median time to first tolerated meal was 25.3 and 32.6 h in the ipamorelin and placebo groups, respectively (p = 0.15). LIMITATIONS: This proof of concept study was small and enrolled patients with a broad range of underlying conditions. CONCLUSIONS: Ipamorelin 0.03-mg/kg twice daily for up to 7 days was well tolerated. There were no significant differences between ipamorelin and placebo in the key and secondary efficacy analyses.

Ghrelin and ghrelin mimetics stimulate appetite and enhance gastric motility. The present study investigates whether ipamorelin, a selective growth hormone secretagogue and agonist of the ghrelin receptor, would accelerate gastrointestinal transit and ameliorate the symptoms in a rodent model of postoperative ileus (POI). Fasted male rats were subjected to laparotomy and intestinal manipulation. At the end of surgery, a dye marker was infused in the proximal colon to evaluate postsurgical colonic transit time, which was the time to the first bowel movement. In addition, fecal pellet output, food intake, and body weight were monitored regularly for 48 h. Ipamorelin (0.01-1 mg/kg), growth hormone-releasing peptide (GHRP)-6 (20 microg/kg), or vehicle (saline) were administered via intravenous bolus infusion after a single dosing or a 2-day repetitive dosing regimen (four doses a day at 3-h intervals). Compared with the vehicle, a single dose of ipamorelin (1 mg/kg) or GHRP-6 (20 microg/kg) decreased the time to the first bowel movement but had no effect on cumulative fecal output, food intake, or body weight gain measured 48 h after the surgery. In contrast, repetitive dosing of ipamorelin (0.1 or 1 mg/kg) significantly increased the cumulative fecal pellet output, food intake, and body weight gain. The results suggest that postsurgical intravenous infusions of ipamorelin may ameliorate the symptoms in patients with POI.

PURPOSE: To examine the pharmacokinetics (PK) and pharmacodynamics (PD) of ipamorelin, a growth hormone (GH) releasing peptide, in healthy volunteers. METHODS: A trial was conducted with a dose escalation design comprising 5 different infusion rates (4.21, 14.02, 42.13, 84.27 and 140.45 nmol/kg over 15 minutes) with eight healthy male subjects at each dose level. Concentrations of ipamorelin and growth hormone were measured. RESULTS: The PK parameters showed dose-proportionality, with a short terminal half-life of 2 hours, a clearance of 0.078 L/h/kg and a volume of distribution at steady-state of 0.22 L/kg. The time course of GH stimulation by ipamorelin showed a single episode of GH release with a peak at 0.67 hours and an exponential decline to negligible GH concentration at all doses. The ipamorelin-GH concentration relationship was characterized using an indirect response model and population fitting. The model employed a zero-order GH release rate over a finite duration of time to describe the episodic release of GH. Ipamorelin induces the release of GH at all dose levels with the concentration (SC50) required for half-maximal GH stimulation of 214 nmol/L and a maximal GH production rate of 694 mIU/L/h. The inter-individual variability of the PD parameters was larger than that of the PK parameters. CONCLUSIONS: The proposed PK/PD model provides a useful characterization of ipamorelin disposition and GH responses across a range of doses.

Performance-enhancing drugs (PEDs) marketed as "research compounds" include unregulated peptides intended to modulate the growth hormone-insulin-like growth factor-1 (GH-IGF-1) axis. The agents most commonly encountered in clinical practice and online self-administration protocols include growth hormone-releasing hormone (GHRH) analogues (e.g., sermorelin, tesamorelin, CJC-1295 with Drug Affinity Complex [DAC], CJC-1295 without DAC), growth hormone secretagogues (GHS; e.g., growth hormone-releasing peptide-2 (GHRP-2), growth hormone-releasing peptide-6 (GHRP-6), hexarelin, ipamorelin), the growth hormone (GH) fragment - AOD9604 (hGH 176-191), and insulin-like growth factor-1 (IGF-1) analogues (e.g., pegylated mechano growth factor (PEG-MGF), IGF-1 Long R3 (IGF-1 LR3)). Reported adverse effects span endocrine and metabolic disturbances (including prolactin and cortisol elevations, appetite changes, and dysglycaemia), fluid retention syndromes, musculoskeletal symptoms (myalgia/arthralgia), and injection-site reactions. Given the absence of regulatory approval for physique- or performance-related indications and the uncertainty surrounding product composition, dose, and stacking practices in unregulated supply chains, clinicians increasingly require a pragmatic framework to interpret symptoms and laboratory abnormalities in patients using these compounds. This narrative review contrasts peer-reviewed pharmacokinetic/pharmacodynamic and clinical evidence with commonly encountered online self-administration protocols, stratifying peptides into evidence tiers from regulatory-grade randomized trial data to a complete absence of human studies, and highlights the resulting uncertainty around putative performance and recomposition benefits. We summarise structural characteristics, pharmacologic effects, and commonly reported dosing patterns, and we synthesise clinically relevant adverse effects with particular attention to hormonal imbalance, endocrine-metabolic risk, and biologically plausible but unproven mitogenic concerns. Finally, we propose a clinically oriented assessment algorithm to support exposure history taking, triage of symptom domains, and risk communication without legitimising off-label peptide regimens.

BACKGROUND: Injectable peptides are increasingly promoted for musculoskeletal recovery, tissue repair, and performance enhancements; however, clinical adoption has outpaced high-quality evidence and regulatory consensus. PURPOSE: To summarize contemporary human and translational evidence (January 1, 2020-August 31, 2025) for injectable peptides relevant to orthopaedics and sports medicine, and to clarify safety, product quality, regulatory, antidoping implications, and clinical outcomes. STUDY DESIGN: Structured narrative review. METHODS: PubMed/MEDLINE, Embase, and Web of Science were searched (January 1, 2020-August 31, 2025). Eligible studies included randomized controlled trials, prospective human studies, and translational investigations directly applicable to musculoskeletal care; noninjectable formulations and nonmusculoskeletal indications were excluded. Results were synthesized qualitatively; risk of bias for human trials was appraised using standard tools. RESULTS: Five functional peptide classes were identified. Glucagon-like peptide-1 receptor agonists (e.g., semaglutide) are the only class supported by reproducible randomized evidence of symptomatic improvement in knee osteoarthritis, with benefits primarily mediated by clinically meaningful weight loss and putative anti-inflammatory effects, whereas structural cartilage modification remains unproven. Collagen-derived injectable preparations show preliminary postoperative symptom/early recovery benefits in small, single-center prospective human studies. Regenerative peptides (e.g., body protection compound-157 and thymosin derivatives) and growth hormone axis secretagogues (e.g., CJC-1295, ipamorelin, and tesamorelin) remain investigational, with uncertain safety profiles, product quality concerns, and widespread antidoping restrictions. CONCLUSIONS: Injectable peptides for sports medicine remain largely experimental. Clinical use should be confined to approved metabolic agents for indicated conditions and to rigorously designed research protocols. Clinicians caring for athletes must counsel patients regarding uncertain efficacy, product quality, safety risks, and antidoping implications. LEVEL OF EVIDENCE: Level V. See Instructions for Authors for a complete description of levels of evidence. STRENGTH OF RECOMMENDATION TAXONOMY: Predominantly C.

BACKGROUND: Peptide therapeutics represent an emerging frontier in gerontological medicine, targeting fundamental hallmarks of aging including metabolic dysfunction, telomere attrition, tissue repair impairment, and hormonal decline. OBJECTIVE: To comprehensively review the mechanisms, clinical applications, evidence base, and safety profiles of therapeutic peptides with demonstrated or potential applications in healthy aging and age-related conditions. METHODS: A comprehensive narrative review was conducted through systematic searches of PubMed, Scopus, and regulatory databases (FDA, WADA) from inception through January 2026. Search terms included "peptide therapeutics," "aging," "gerontology," "healthspan," combined with specific peptide names (tirzepatide, epitalon, GHK-Cu, BPC-157, TB-500, Semax, CJC-1295, ipamorelin, bremelanotide). Peer-reviewed articles, clinical trials, regulatory documents, and preclinical studies were evaluated. A total of 20 primary sources were selected based on relevance, methodological quality, and contribution to understanding peptide mechanisms and clinical outcomes in aging populations. RESULTS: Nine peptides were identified spanning diverse aging interventions: metabolic restoration (tirzepatide), telomere biology (epitalon), dermal regeneration (GHK-Cu), tissue repair (BPC-157, TB-500), neuroprotection (Semax), growth hormone modulation (CJC-1295, ipamorelin), and sexual function (bremelanotide). FDA-approved agents demonstrated robust safety profiles from large-scale trials. Non-approved peptides showed promising preclinical and limited clinical evidence but lack long-term safety data and systematic validation. Significant knowledge gaps include optimal dosing regimens, combination therapy effects, and biomarkers for monitoring efficacy. CONCLUSION: Therapeutic peptides offer mechanistically diverse approaches to multiple aging hallmarks. While FDA-approved agents demonstrate clinical potential, investigational peptides require rigorous validation through well-designed clinical trials to establish safety and efficacy for healthspan extension.