In vivo magnetic resonance spectroscopy (MRS) allows for the non-invasive study of tissue metabolism. In this field, small animal models have greatly contributed to both technological advances and the development of applications to follow disease progression and response to treatments. The limited application of MRS in patients is primarily due to its relatively low sensitivity. With the developments of magnets with higher field strengths and hyperpolarized 13C-labeled substrates, it is expected that the impact of MRS technology in the study of tissue metabolism will grow in the coming years.