Used as a spin label in electron paramagnetic resonance (EPR) spectroscopy to study membrane dynamics and lipid-protein interactions. Its rigid steroidal structure allows it to integrate into lipid bilayers, providing insights into membrane fluidity, phase transitions, and molecular motion. The free radical nitroxide group enables detection of local environmental changes in biological membranes. Commonly applied in biophysical research to probe the organization and behavior of model and cellular membranes under varying conditions.