A new era of doping? Use of peptide and peptide-analog drugs in recreational and professional sport and bodybuilding: a critical review

The pursuit of pharmacological enhancement in sport has evolved from the widespread use of anabolic-androgenic steroids (AAS) to novel agents such as peptides and peptide analogues. Marketed as more selective and ostensibly safer alternatives, peptides-including growth hormone secretagogues (e.g., Ipamorelin), growth hormone-releasing hormone analogues (e.g., CJC-1295, Sermorelin), and synthetic fragments (e.g., Frag 176-191, KPV)-are promoted for muscle growth, fat metabolism, recovery, and anti-inflammatory effects. Their pharmacological profiles, including enhanced stability and receptor selectivity, have made them attractive in both medical research and bodybuilding communities. Despite their growing popularity, the clinical evidence supporting peptide use in sport is limited. Most published studies examine therapeutic applications under controlled dosing regimens, not the supraphysiological or combined protocols common in bodybuilding. Emerging data highlight potential risks: cardiovascular strain, insulin resistance, dyslipidemia, and psychiatric instability. The largely unregulated supply chain exacerbates these dangers, as products are often mislabeled or contaminated. Regulatory bodies such as the World Anti-Doping Agency (WADA) have responded by expanding detection technologies, yet analytical challenges remain due to peptides' structural similarity to endogenous hormones and short half-lives. Beyond elite sport, the extent of peptide use in the general population is unknown. Anecdotal reports and widespread promotion on social media suggest growing uptake among recreational gym-goers, including younger individuals, but prevalence studies are lacking. This represents a critical gap in current knowledge. In conclusion, peptides represent a new phase in performance enhancement but remain experimental substances with poorly defined long-term risks. Until longitudinal data clarify their safety and prevalence, peptide use in both competitive and recreational settings should be considered high-risk and ethically problematic.