Related Terms

Amphetamines, anabolic steroids, androstenediol, androstenedione, athlete nutrition, athletic performance, blood doping, caffeine, carbohydrate loading, carnitine, chromium, creatine, DHEA, dehydroepiandrosterone, ephedrine, ergogenic aids, exercise, fitness, human growth hormone, leucine, multivitamins, phosphates, protein, sports performance, steroids, yohimbine.
Note: This monograph primarily covers herb and supplement ergogenic aids. For more information about other methods, please see individual monographs.


A performance enhancer, also known as an ergogenic aid, is a substance or practice that improves an individual's strength, speed, endurance or speed of recovery. Ergogenic aids may include mechanical aids, pharmacological aids, physiological aids, nutritional aids and psychological aids.
Many forms of ergogenic aids are regularly incorporated into the training of an athlete. Such methods may be as harmless as friends cheering on the sideline to boost self-esteem or weight training to increase strength when on the field. Less conventional methods include nutritional aids like high-protein diets, physiological aids like sports drinks to replace lost electrolytes and mechanical aids like weighted vests.
Several substances are banned by most major sporting organizations and/or are illegal. These include anabolic steroids, androstenedione, blood doping, DHEA, and ephedrine. In addition to allowing the user an unfair advantage, these methods may be unsafe for the athlete. Based on expert opinion, many aids have negative repercussions. Aids, such as vanadium and boron have also been used, but are typically not recommended due to possible adverse effects.
Athletes are regularly screened for such illegal methods in professional sports and the Olympics. However, use of illegal ergogenic aids also occurs at high school levels. Organizations such as the National Collegiate Athletic Association (NCAA) have also initiated extensive public outreach campaigns to educate and dissuade athletes from using steroids or blood doping.

Theory / Evidence

Many herbs and supplements are purported to have performance enhancing effects. However, scientific evidence on the safety and efficacy of different treatments varies. Before taking any herb or supplement, consult with a qualified healthcare provider to learn about potential side effects and interactions.
Androstenedione: The hormone androstenedione is said to enhance athletic performance and strength by increasing testosterone production, thereby building muscle. However, in double-blind studies, it neither altered total testosterone levels, nor improved sports performance, strength or lean body mass. It did, however, increase estrogen levels, which might increase the risk of liver cancer and heart disease. Androstenedione does appear to raise testosterone levels in women, but it is not clear whether this would produce favorable results.
Boron: Boron has been reported to increase serum testosterone levels and subsequently the lean body mass and strength. However, scientific evidence is lacking. Clinical studies suggest that boron supplementation is more likely to increase estrogen than testosterone. Increased estrogen is not likely to have a sports performance benefit in men, while in women it might increase risk of breast cancer.
Creatine: Creatine monohydrate is a compound produced by the body that helps release energy in the muscles. It is found in protein-rich foods like meat or fish, or it can be taken as a nutritional supplement. Possible side effects include: stomach cramps, muscle cramps, nausea, vomiting and diarrhea. High doses of creatine may damage the liver, kidney or heart. Long-term side effects are unknown.
DHEA (dehydroepiandrosterone): Athletes have used DHEA based on the idea that (like phosphatidylserine) it might limit the body's response to cortisol and thereby increase muscle tissue growth. However, studies have reported mixed results.
HMB: HMB (beta-hydroxy beta-methylbutyric acid) is a chemical that occurs naturally in the body when the amino acid leucine breaks down. High concentrations of leucine are found in muscles. During athletic training, damage to the muscles leads to the breakdown of leucine as well as increased HMB levels. Some evidence suggests that taking HMB supplements might signal the body to slow down the destruction of muscle tissue. On this basis, HMB has been studied as a supplement for enhancing strength and muscle mass. However, larger studies are necessary to establish whether HMB has beneficial affects.
Policosanol: Policosanol is a mixture of waxy substances manufactured from sugarcane. The main active component of policosanol is octacosanol, which is also made from wheat germ oil. Both are marketed as performance-enhancing dietary supplements said to increase muscle strength and endurance and improve reaction time and stamina. However, the only evidence for policosanol as a performance enhancer comes from one small double-blind trial with marginal results.
Vanadium: Vanadium as been suggested for use by bodybuilders based on its effects on insulin, but there is no evidence that it helps. Studies in humans and animals suggest that vanadium can cause toxic effects and might accumulate in the body if taken to excess.

Author information

This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).


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