Synephrine

Synephrine (or oxedrine) is an alkaloid, a naturally-occurring plant constituent, and is commonly used as a drug for causing weight loss. While its effectiveness is widely debated, synephrine has gained significant popularity as an alternative to ephedrine, a related substance which has been made illegal or restricted in many countries due to health risks and its use as a precursor in the illicit manufacturing of methamphetamine. There is however no diversion of synephrine for the manufacture of amphetamines, since the presence of the phenolic group and absence of an α-methyl group in its molecular structure makes it unsuitable for such purposes. Synephrine is derived primarily from the immature fruit of Citrus aurantium, a relatively small citrus tree, of which several of its more common names include Bitter Orange, Sour Orange, and Zhi shi. Products containing bitter orange or synephrine are suspected of causing adverse cardiovascular reactions. Among other commonly consumed citrus fruits, clementine mandarins have high levels of synephrine. Dietary supplements generally supply single oral doses of 3–30 mg, while as a pharmaceutical agent it is given orally or by parenteral injection in 20–100 mg doses as a vasoconstrictor to hypotensive patients.