Displaying 6 results of Equilin Stable Isotopes Equilin stable isotopes are a valuable tool in the study of hormone metabolism and equine physiology. These isotopes, which are non-radioactive versions of equilin, a naturally-occurring hormone found in horses, allow researchers to track the movement and fate of equilin in the body. This information can be used to better understand hormone pathways and develop new treatments for equine health issues.