These terms are used to refer to the same substance derived from the plant Ephedra. (There are many common names for these evergreen plants, including squaw tea and Mormon tea.) Ephedra is a shrub-like plant that is found in desert regions in central Asia and other parts of the world. The dried greens of the plant are used medicinally. Ephedra is a stimulant containing the herbal form of ephedrine, an FDA-regulated drug found in over-the-counter asthma medications.
In the United States, ephedra and ephedrine are sold in health food stores under a variety of brand names. Ephedrine is widely used for weight loss, as an energy booster, and to enhance athletic performance. These products often contain other stimulants, such as caffeine, which may have synergistic effects and increase the potential for adverse effects. Ephedra is often touted as the "herbal fen-phen."
Ephedra's main active medical ingredients are the alkaloids ephedrine and pseudoephedrine. The ephedras also contain various tannins and related chemicals.The stem contains 1-3% total alkaloids, with ephedrine accounting for 30-90% of this total. The concentrations of these alkaloids depends upon the particular species of ephedra used.