Spin relaxation times, T 1 , T 2 and heteronuclear NOE relaxation (hetNOE), measured with solution state NMR from isotopically labelled N atoms in peptide backbone are often used to determine protein dynamics by exploiting their connection to rotational dynamics of N-H bond vectors via Redfield equations. Spin relaxation times from proteins are typically interpreted using Lipari-Szabo formalism or its extensions, where bond vector rotational motions are assumed to compose of overall motion and one or more independent modes of internal motions, and parameters describing these motions are then solved by fitting to the experimental data. However, for peptides embedded in disordered lipid-like aggregates, it is not clear which kind of rotational modes should be used in these calculations, and if all molecules in aggregates rotate together as a rigid object or if peptides rotate independently from other molecules. In addition, the number of molecules in each aggregate and the potential formation of dimers or higher multimers of peptides may affect rotational dynamics.