Injectable Peptides in Sports Medicine: A Structured Narrative Review of Evidence, Safety, and Antidoping Implications.

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.