Ephedra is both a stimulant (similar to adrenaline) and a thermogenic. It stimulates the brain, increases heart rate, constricts blood vessels (increasing blood pressure), and expands bronchial tubes (making breathing easier). Its thermogenic properties cause an increase in metabolism, evidenced by an increase in body heat.

Side effects of ephedra may include irritability, nervousness, dizziness, trembling, headache, vomiting and hyperthermia. Chemical dependence may also develop.