Erythropoietin is a molecular marvel due to its ability to improve people's health and lives when used for medical treatment. Its targeted action on red blood cell production makes it a life-changing medication for individuals suffering from specific conditions. However, its use outside clinical settings, particularly in sport, has sparked debate over safety, fairness, and long-term health risks. While some view EPO as a therapeutic breakthrough, others raise concerns about misuse, ethical boundaries, and the adequacy of current detection methods. Ethical concerns arise regarding the exploitation of EPO for performance enhancement, which undermines the principle of equal opportunity and endangers athlete welfare due to associated health risks. This tension makes EPO a compelling topic at the centre of science, medicine, and public policy.

Above is the core chemical structure of EPO, however, this can differ slightly when sugar chains are added, lengthening branches at the nitrogen and oxygen-linked sites. EPO is a protein with sugar chains attached, and those sugar chains can differ depending on how and where the hormone is made. These differences don’t change the core protein itself, but they do affect how long EPO lasts in the body and how well it works. For example, EPO made naturally in the human body might have slightly different sugars compared to EPO made in a lab for medical use. These structural differences are important, not just for how EPO works, but also for detecting if someone is using it illegally in sport.