Proton spin lattice relaxation times (T₁) are reported for the -NMe₃, [CH₂]_n, and terminal methyl protons in sonicated samples of aqueous dispersions of lecithins; these three resonances have distinct T₁ values at each temperature measured, so that spin-diffusion to the terminal methyl or the -NMe₃ cannot be the dominant relaxation mechanism; the effect of the crystalline to lamellar liquid crystalline phase transition is discussed.