For the great interest in protein hydration studies, the hydration of nonapeptide oxytocin dissolved in D₂O/H₂O was investigated by 2D NOE spectra. A recent established method was used to conduct the research in an unperturbed environment at temperatures well below 0 degree Celsius, i.e. in the supercooled water. The cross relaxation rates (σNOEs) between water molecules and polypeptide protons are compared with those from a previous study in an acetone-water mixture solvent. The comparison revealed that the use of acetone for freezing point depression may significantly affect surface water molecules. Hydration studies in supercooled water thus promise to yield novel insight into surface hydration of biological macromolecules. The σNOEs are also used to calculate the water life time based on various spatial motional models. The results of the model calculation are discussed and the NOE approach for studying protein hydration is carefully reviewed.