Objectives: Analyzing the relationship between serum Apelin-13 levels and erectile dysfunction severity Background: Both hypercholesterolemic and hyperglycemic mice, two well-known vasculogenic ED models, have recently been revealed to have an elevated Apelin system, and intracavernosal acute injection of Apelin has been proven to restore erectile functioning in both animals (19). Data Sources: We did this by searching and examining the Medline databases (Pub Med and Medscape) and looking for studies that looked at the probable link between serum Apelin-13 and erectile function and its connection to severity of erectile dysfunction up to 2020. Study Selection: The quality of each study was evaluated separately before being accepted. If they met any of the following criteria, we considered them for inclusion: 1. It's written in English and published. 2. Appearing in publications with a strict peer-review process. Third, explain how the level of serum Apelin-13 may be linked to erectile function and how this may affect the severity of erectile dysfunction.Data Extraction: Studies were not included if they did not meet the inclusion criteria. Ethical permission, eligibility criteria, controls, information, and well-defined evaluation measures were all factors in determining the study's quality. Our concerned research results were captured by independently abstracting data utilising a data collecting form from each qualifying study.. Conclusions: Serum Apelin -13 levels are lower in individuals with erectile dysfunction, and this drop is associated with elevated triglyceride and body-mass index levels.