Tyramine hydriodide (4-(2-aminoethyl)phenol hydriodide) is the iodide salt of tyramine, a biogenic amine and decarboxylation product of tyrosine. It serves as a key intermediate in organic synthesis for pharmaceutical applications, particularly in the development of compounds targeting the sympathetic nervous system, such as beta-adrenergic antagonists and antihistamines. The hydriodide form provides enhanced solubility, stability, and crystallinity, facilitating purification and handling in medicinal chemistry. Widely used in biochemical research to study monoamine oxidase (MAO) activity, trace amine-associated receptors (TAARs), and pathways involved in neurotransmission, migraine, and hypertension.