Medical use
Both ephedrine and pseudoephedrine increase blood pressure and act as bronchodilators, with pseudoephedrine having considerably less effect.Ephedrine may decrease motion sickness, but it has mainly been used to decrease the sedating effects of other medications used for motion sickness.Ephedrine is also found to have quick and long-lasting responsiveness in congenital myasthenic syndrome in early childhood and also even in the adults with a novel COLQ mutation. Weight loss
Ephedrine promotes modest short-term weight loss, specifically fat loss, but its long-term effects are unknown. In mice, ephedrine is known to stimulate thermogenesis in the brown adipose tissue, but because adult humans have only small amounts of brown fat, thermogenesis is assumed  to take place mostly in the skeletal muscle. Ephedrine also decreases gastric emptying. Methylxanthines such as caffeine and theophylline have a synergistic effect with ephedrine with respect to weight loss. This led to creation and marketing of compound products. One of them, known as the ECA stack, contains ephedrine with caffeine and aspirin. It is a popular supplement taken by bodybuilders seeking to cut body fat before a competition. Recreational use
As a phenethylamine, ephedrine has a similar chemical structure to amphetamines and is a methamphetamine analogue having the methamphetamine structure with a hydroxyl group at the β position. Because of ephedrines structural similarity to methamphetamine, it can be used to create methamphetamine using chemical reduction in which ephedrines hydroxyl group is removed; this has made ephedrine a highly sought-after chemical precursor in the illicit manufacture of methamphetamine.
The isomer which is marketed is (−)-(1R,2S)-ephedrine.Ephedrine hydrochloride has a melting point of 187−188 °C.In the outdated D/L system (+)-ephedrine is also referred to as D-ephedrine and (−)-ephedrine as L-ephedrine (in which case, in the Fisher projection, the phenyl ring is drawn at the bottom).Often, the D/L system (with small caps) and the d/l system (with lower-case) are confused. The result is that the levorotary l-ephedrine is wrongly named L-ephedrine and the dextrorotary d-pseudoephedrine (the diastereomer) wrongly D-pseudoephedrine. The IUPAC names of the two enantiomers are (1R,2S)- respectively (1S,2R)-2-methylamino-1-phenylpropan-1-ol. A synonym is erythro-ephedrine. Sources
Agricultural
Ephedrine is obtained from the plant Ephedra sinica and other members of the genus Ephedra, from which the name of the substance is derived. Raw materials for the manufacture of ephedrine and traditional Chinese medicines are produced in China on a large scale. As of 2007, companies produced for export US$13 million worth of ephedrine from 30,000 tons of ephedra annually, or about ten times the amount used in traditional Chinese medicine. Synthetic
Most of the l-ephedrine produced today for official medical use is made synthetically as the extraction and isolation process from E. sinica is tedious and no longer cost effective. Biosynthetic
Ephedrine was long thought to come from modifying the amino acid L-phenylalanine. L-Phenylalanine would be decarboxylated and subsequently attacked with ω-aminoacetophenone. Methylation of this product would then produce ephedrine. This pathway has since been disproven. A new pathway proposed suggests that phenylalanine first forms cinnamoyl-CoA via the enzymes phenylalanine ammonia-lyase and acyl CoA ligase.