Used in peptide synthesis and biochemical research as a protected form of the thyroid hormone T3 (triiodothyronine). The Boc (tert-butoxycarbonyl) group allows for selective protection of the amino group, enabling controlled chemical modifications in multi-step syntheses. Commonly applied in the development of thyroid hormone analogs, receptor binding studies, and metabolic pathway investigations. Also utilized in the preparation of labeled derivatives for tracer studies and immunoassays.