A method and apparatus for producing a hyperpolarized sample material for use in an NMR investigation provides for a cryogenic region having a target material containing a first hyperpolarizable nuclear species, a second hyperpolarizable nuclear species, and a nuclear spin polarizing agent, wherein the first nuclear species has a higher magnetic moment than the second nuclear species. Microwave energy is used to excite electron spin transitions in the polarizing agent in the presence of a magnetic field. The first hyperpolarizable nuclear species is thereby caused to interact with the electron spin system in the polarizing agent and generate hyperpolarization of at least the first nuclear species of the target material. The target material is then subjected to a lowered magnetic field, wherein the lowered magnetic field facilitates polarization transfer by nuclear thermal mixing between the species to thereby hyperpolarize the second nuclear species.