Fentanyl Stable Isotopes are a type of chemical compound that are used in medical research and drug testing. These isotopes are stable forms of fentanyl, a synthetic opioid that is commonly used as a pain medication. The stable isotopes of fentanyl are used to create precise and accurate measurements in laboratory experiments, allowing researchers to better understand the effects of this powerful drug on the body. They are also used to develop new drug formulations and to improve the safety and efficacy of existing medications.