It probably goes without saying, but ephedra is one controversial supplement. At times, it's used in products standardized for ephedrine alkaloids (the active components) with or without the addition of caffeine. I don't think anyone doubts the published research demonstrating a positive effect of ephedrine and caffeine for weight loss/fat loss or energy enhancement. However, what applies for the synthetic ephedrine may not apply for the herbal "equivalent." .
Ephedra is probably the most popular of the thermogenic dietary supplements. Ephedra is an extract of (meaning it's isolated from, or taken out of) the Ma Huang plant. Ma Huang naturally grows in Europe, Asia and the U.S. Ephedra is also found in other plants such as sida cordfiolia and E. gerardiana. The synthetic drug ephedrine is also based on the herbal equivalent, ephedra. Ephedrine is a stimulant that in medical circles is known as a beta-2-agonist. However, recent research indicates that synthetic ephedrine also acts upon the beta-3 receptor, which is active in the predominant white adipose tissue. Agents, natural or synthetic, that affect the beta-2 and 3 receptors are considered ideal for weight loss. Ephedra is composed of five different substances known as alkaloids. Ephedra in dietary supplements is typically standardized to contain six to eight percent of the active ephedrine alkaloids. This is to ensure that enough of the compounds responsible for aiding in weight loss are included.
The best bet for the dietary supplement industry is to fund a three-arm clinical trial evaluating synthetic ephedrine/caffeine versus herbal ephedra /caffeine versus placebo. This goal should be to determine if the herbal brethren can produce the same, or better, weight loss and body composition effects while demonstrating fewer perceived and objective side affects. Such a study should have sufficient subjects (more than 120) and be at least three to six months in duration.