A new era of doping? Use of peptide and peptide-analog drugs in recreational and professional sport and bodybuilding: a critical review.
This critical review examines the emerging use of peptides and peptide analogues as performance-enhancing drugs in both competitive sport and recreational bodybuilding. The authors survey a range of compounds — including growth hormone secretagogues (e.g., Ipamorelin), growth hormone-releasing hormone analogues (e.g., CJC-1295, Sermorelin), and synthetic peptide fragments (e.g., Frag 176-191, KPV) — which are promoted in bodybuilding communities for purported benefits in muscle growth, fat loss, recovery, and anti-inflammation. The review notes that these compounds are attractive partly due to their enhanced receptor selectivity and stability compared to older anabolic agents. However, the authors conclude that clinical evidence supporting their use in sport contexts is limited; most existing research addresses therapeutic applications under controlled medical settings, not the high-dose or stacked protocols typical in bodybuilding. The review identifies potential risks including cardiovascular strain, insulin resistance, dyslipidemia, and psychiatric instability. It also highlights the dangers posed by an unregulated supply chain prone to mislabeling and contamination. Anti-doping detection remains challenging due to peptides' structural similarity to endogenous hormones and short half-lives. A key gap identified is the near-complete absence of population-level prevalence data, particularly for recreational users. The authors characterize peptide use in sport as high-risk and ethically problematic pending longitudinal safety evidence.