Complex fluids with high concentrations of crystallizing fatty acids are important for consumer skin care products. These fluids exhibit solid-like elastic behavior at rest, but yield and flow under an applied strain. Such behavior is characteristic of isotropic, space-filling networks. The processing determines the microstructure of these systems, which in turn influences their macroscopic rheological properties. The kinetics of crystal growth in model system compositions, comprising (by weight) 9% sodium dodecyl sulfate, 3% cocamidopropyl betaine, and different specified amounts of palmitic acid in H 2 O or D 2 O, were studied by time domain nuclear magnetic resonance (TDNMR) and differential scanning calorimetry (DSC). The data were analyzed using the Avrami equation; both DSC and TDNMR gave consistent Avrami exponent values of approximately 1.5 for formulations with 11wt% and greater amounts palmitic acid content. The Avrami exponent is consistent with two-dimensional crystal growth limited both by diffusion and surface incorporation. The solids content at 25°C was found to be proportional to the concentration of palmitic acid level above its solubility limit of ca. 2wt%. TDNMR, combined with DSC, microscopy, and rheology provide valuable insights into the molecular structure and mechanism of crystallization in surfactant/fatty acid systems.