Adiabatic pulses are commonly used in clinical MRI due to their insensitivity to B1 inhomogeneity and uniform flip angle over a selected bandwidth. When applied to white matter, they are generally assumed to saturate the magnetization of the non-aqueous protons in myelin. We performed adiabatic inversion recovery experiments on bovine brain in vitro using a solid state NMR spectrometer to directly observe the effects of adiabatic inversions on the non-aqueous signal. Substantial non-aqueous magnetization remains after typical adiabatic pulses. The state of the non-aqueous magnetization seriously impacts measurement of T1, yielding values dependent on the form of inversion pulse used.