3-Indoleacetic acid-d4 (Indole-3-acetic acid-d4, 3-IAA-d4) is the deuterium labeled 3-Indoleacetic acid (HY-18569)[1]. 3-Indoleacetic acid (Indole-3-acetic acid) is the most common natural plant growth hormone of the auxin class. It can be added to cell culture medium to induce plant cell elongation and division[2].