TABLE 1.
A paediatrician’s glossary of ergogenic aids
| Ergogenic agent | Purported actions | Proven effects | Side effects |
|---|---|---|---|
| Amino acid mixtures: arginine, lysine, ornithine | Increases exercise-induced HGH release via oral ingestion. | Pre-exercise oral amino acid supplementation does not augment HGH release. No increased exercise benefit above exercise alone. | Large doses cause stomach discomfort and diarrhea. |
| Anabolic steroids: androstenedione, dehydroepiandrosterone (DHEA) | Improves muscle mass and strength beyond inherent genetic limits. | Few studies of how DHEA affects anabolic activity in younger athletes whose levels are already very high. | Long-term use associated with liver tumours, severe arteriosclerosis, myocardial infarction, stroke and premature death due to severe tissue-damaging effects, some of which are irreversible. |
| Arginine | Needed for periods of growth and recovery after injury; precursor for protein, creatine and nitric oxide biosynthesis; increases HGH release. | Very high intakes may increase HGH levels, but lower doses do not increase HGH release and may even impair HGH release in younger adults. | None at usual doses. |
| Carnitine | Improves skeletal muscle function and athletic performance in healthy individuals | No compelling evidence that carnitine supplementation improves physical performance in healthy subjects. | Oral carnitine doses of several grams cause no significant clinical toxicity. |
| Chromium | Promoted as a nonsteroidal anabolic hormone to increase lean body mass. | No specific ergogenic effect has been demonstrated. | Interferes with iron and zinc metabolism; addition of ephedrine to chromium can cause hypertension, stroke and death. |
| Copper | Critical nutrient. | No studies have demonstrated a specific ergogenic effect from supplementation beyond usual dietary intake. | Excessive supplementation can cause GI distress, nausea, vomiting and diarrhea, as well as intravascular hemolysis. |
| Creatine | Provides increased power during anaerobic, short-duration, high-intensity activity. | No benefit on endurance exercise or maximal oxygen uptake. Not tested in those younger than 18 years. | Significant negative effects, mostly GI cramping and distress. |
| Ginseng | Increases resistance to catabolic effects of exercise, with a secondary consequence of prolonged time to exhaustion with extreme exercise. | None of the proposed mechanisms of action have been proven, nor have the benefits been demonstrated. | Bioavailability may be low, with no active ginseng in some products. Excess leads to hypertension, insomnia, diarrhea and irritability, but all or some of these effects may be due to coexistent ephedrine or ma huang. |
| Glucosamine | Regenerates cartilage and aids joint lubrication and shock absorption, and has anti-inflammatory effects. | No direct evidence that repair or protection occurs in vivo, or that the use of glucosamine sulfate changes articular cartilage either structurally or functionally. | In North America, glucosamine is a highly purified derivative of shellfish, which may provoke allergic reactions. |
| Magnesium | Increases physical power through increased muscle mass, with an associated increase in aerobic power and endurance. | There is no proven effect on performance. | Excessive intake causes GI upset, nausea, vomiting, diarrhea, muscle weakness and interference with the absorption of calcium. |
| Multivitamins: A and D, B complex, may include many minerals | Helps meet increased requirements of intense exercise and training. | 10 to 50 times the recommended daily intake of all or some of these vitamins for up to nine months did not improve aerobic performance. Can address dietary deficiencies due to calorie restriction or high carbohydrate intake. | Hypervitaminosis A may cause bone resorption and bone abnormalities. Hypervitaminosis D causes anorexia, nausea, vomiting, constipation, weakness and weight loss. Both cause hypercalcemia. |
| Ornithine | Promotes muscle building by increasing levels of anabolic (growth-promoting) hormones such as insulin and HGH. | Most human research does not support these claims at reasonable intake levels. | Very high amounts cause many GI side effects. |
| Vitamin E | Reduces delayed-onset muscle soreness in eccentric exercise. | There is no known benefit at low-altitude exercise, and no performance improvement or effect on VO2 max in endurance athletes. | Can act as an anticoagulant and may increase the risk of bleeding problems. |
| Zinc | Increases muscle contraction strength, explosive power and power endurance. | No evidence of a measurable ergogenic effect in controlled studies. | Can cause copper deficiency and interfere with tetracycline activity. |
| Amphetamines, ephedrine | Stimulates exercise performance. | May increase time to exhaustion by masking the physiological response to fatigue, but have not been shown to result in any significant performance improvements. | Anxiety, tremor, tachycardia and hypertension. Can increase blood glucose and lactate. |
| Caffeine | Stimulates exercise performance. | The potential benefits of caffeine are lost in several confounding variables. Most studies show minimal to no benefit in untrained, recreational athletes. Caffeine plus ephedrine may increase performance during submaximal steady-state aerobic exercise. | Anxiety, tremor, tachycardia and hypertension. High caffeine intake may accelerate bone loss. Combinations of caffeine with other stimulants (eg, ephedrine) have been linked to fatal events. |
| Narcotic analgesic | Allows extension of exercise performance. | Not necessarily ergogenic. | Harmful if used to allow participation of an athlete with a severe injury. |
| Marijuana, cocaine | Enhances athletic performance. | Marijuana does not increase strength. Cocaine and other sympathomimetic drugs have little or no effect on athletic performance. | Addictive and illegal. |