Used primarily in medical and biochemical research to study thyroid hormone function and metabolism. It is a synthetic form of a thyroid hormone, often employed in laboratory settings to investigate the effects of thyroid hormones on cellular processes, gene expression, and metabolic regulation. Additionally, it serves as a reference standard in analytical methods to measure thyroid hormone levels in biological samples. In clinical studies, it helps in understanding thyroid-related disorders and evaluating the efficacy of thyroid hormone therapies.