Electron spin resonance (ESR), also called electron paramagnetic resonance (EPR), spectroscopy of lipid-soluble spin labels is commonly used to study model and biological membranes. The most common spin labels for these applications are stearic acid spin labels (SASLs; doxyl stearates).

Ekaterina A. Vishnyakova, Andres E. Ruuge, Elena A. Golovina, Folkert A. Hoekstra, Alexander N. Tikhonov. Spin-labeling study of membranes in wheat embryo axes. 1. Partitioning of doxyl stearates into the lipid domains. Biochimica et Biophysica Acta (BBA) – Biomembranes. Volume 1467, Issue 2, 2000, Pages 380-394, ISSN 0005-2736,