Background and Ingredients
There has been a recent explosion of energy pills on the market intended for people trying to lose weight, athletes looking to improve performance, or those looking for more energy to get them through the day. Due to the untested nature of many of these products, it can be difficult to determine the efficacy and safety of long-term use. However, we can draw some generalizations based upon what we know about the ingredients and their effects on the human body.
Most energy pills contain combinations of natural herbs and essences which are metabolized by the body into energy-producing chemicals. Some of these include ma huang, guarana, kola nut, and ginseng. Ma huang is a natural source of the chemical ephedrine, and guarana and kola nut contain high levels of caffeine.
Ephedrine and Caffeine
Ephedrine has been used to treat narcolepsy and depressive states, though it has been replaced by newer medications. It stimulates the heart and constricts the blood vessels while dilating the bronchioles in your lungs. These activities reflect the sympathomimetic or "fight-or-flight" stimulating effects of the drug. In addition, it acts as a stimulant in your central nervous system, creating the impression of increased energy and wakefulness. Ephedrine can cause serious cardiovascular emergencies, especially in patients with known or unrecognized underlying heart problems. Herbal preparations may have varying amounts of ma huang, leading to a potentially deadly overdose, so the FDA banned their sale in the United States in 2004.
According to "Goodman & Gilman's The Pharmacological Basis of Therapeutics, 11e," caffeine is the most widely used psychoactive substance in the world. Its stimulant effects are primarily the result of blocking the action of adenosine in the brain. Adenosine causes mild sedative effects, so blocking it causes increased wakefulness and energy. Interestingly, although even mild caffeine use on the order of one to two cups per day can result in withdrawal symptoms if abruptly stopped, it's rare to experience a loss of control or difficulty stopping the drug if desired. For this reason, it's not considered addictive.
Effectiveness
According to the March 2003 issue of the Journal of the American Medical Association, "Ephedrine and ephedra promote modest short-term weight loss (approx 0.9 kg/mo more than placebo) in clinical trials." However, the same study warns that ephedrine "is associated with increased risk of psychiatric, autonomic, or gastrointestinal symptoms, and heart palpitations." A six-month placebo-controlled trial in the May 2002 issue of the International Journal of Obesity and Related Metabolic Disorders says "herbal ephedra/caffeine (90/192 mg/day) promoted body weight and body fat reduction and improved blood lipids without significant adverse events."
Further study is necessary to fully evaluate the long-term health benefits and side effects of regular ephedrine and caffeine use. In the meantime, if you have an underlying heart condition, avoid excess use of either drug.
References
- Goodman & Gilman's The Pharmacological Basis of Therapeutics, 11e; Laurence L. Brunton, editor-in-chief ; 2006
- The Journal of the American Medical Association; Efficacy and Safety of Ephedra and Ephedrine for Weight Loss and Athletic Performance; Paul G. Shekelle, MD, PhD; Mary L. Hardy, MD; Sally C. Morton, PhD; Margaret Maglione, MPP; Walter A. Mojica, MD, MPH; Marika J. Suttorp, MS; Shannon L. Rhodes, MFA; Lara Jungvig, BA; James Gagné, MD; March 2003
- International Journal of Obesity and Related Metabolic Disorders; Herbal ephedra/caffeine for weight loss: a 6-month randomized safety and efficacy trial.; Boozer CN, Daly PA, Homel P, Solomon JL, Blanchard D, Nasser JA, Strauss R, Meredith T.; May 2002
