Synephrine (p-synephrine) is a naturally occurring protoalkylamine found in the immature fruit peel of Citrus aurantium (bitter orange, zhi shi). It is extracted using aqueous-acid methods and purified to high concentrations. Synephrine is structurally related to epinephrine and acts primarily on beta-3 adrenergic receptors.
It promotes lipolysis and thermogenesis without significant cardiovascular stimulation at recommended doses. It became the leading ephedra alternative in the weight management supplement market after the 2004 ephedra ban. Commercially, synephrine is widely used in fat-burning supplements, sports nutrition products, energy formulations, and metabolic health nutraceuticals.
