Intravenous peptides and amino acids for erectile dysfunction: a narrative review of current applications and future directions.

This narrative review examines intravenous (IV) peptide and amino acid therapies as potential treatments for erectile dysfunction (ED), a condition involving interrelated vasculogenic, hormonal, and neurological mechanisms in which endothelial dysfunction and oxidative stress are central contributors. The authors conducted a PubMed literature search of English-language publications through October 2024, focusing primarily on studies from the past decade. Four compounds were highlighted: PT-141 (bremelanotide), a melanocortin receptor agonist proposed to act via central nervous system pathways; PnPP-19, a spider venom-derived peptide suggested to work through nitric oxide regulation; and the amino acids L-arginine and L-citrulline, both linked to enhanced endothelial function and nitric oxide synthesis. The review notes that these agents operate through mechanisms distinct from phosphodiesterase type 5 (PDE5) inhibitors, potentially offering alternatives or adjuncts for patients unresponsive to standard therapy. The authors conclude that while early evidence is promising, large-scale clinical trials are needed to establish safety profiles, optimal treatment parameters, and potential synergistic effects with existing ED treatments. As a narrative review, it is subject to selection bias and does not pool quantitative data.

Why this grade: This is a narrative review synthesizing existing literature without meta-analytic methods, so it inherits the variable quality of its source studies and cannot independently establish efficacy or safety in humans.