Microcystin-YR is primarily used in research settings to study its effects on biological systems, particularly its role as a hepatotoxin. It is employed in toxicological studies to understand the mechanisms of liver damage and to develop potential treatments for microcystin poisoning. Additionally, it serves as a reference standard in environmental monitoring to detect and quantify the presence of harmful algal blooms in water bodies, ensuring public health and safety. Researchers also use it to investigate the impact of microcystins on aquatic ecosystems and to develop strategies for mitigating their effects.