was chosen as a model system since it is a well-established surrogate for the nonpolar environment of lipid bilayer membranes. From these NMR titrations, we found that the amide and carboxylic acid resonances of SNAC are highly sensitive to sample concentration, as expected for intermolecular hydrogen bond formation. Specifically, the observed upfield shift of the amide resonance with increasing SNAC concentration is attributed to an increase in hydrogen bonding, which deshields the amide and carboxylic acid peaks. Furthermore, at higher SNAC concentrations (>70 mM), the titration curve deviates significantly from a simple 1:1 binding model (Supplementary Fig. ), indicating the formation of larger aggregates, which were also observed by DLS (Fig. ). Additionally, convection-corrected 1 H DOSY NMR spectra show that the diffusion coefficient of SNAC in CDCl₃ decreases with increasing SNAC concentration (Supplementary Fig. ), which is also consistent with SNAC aggregate formation.