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Ergogenic Aids: Nutritional Supplements for Athletes

Ergogenic aids are substances, devices, or practices that enhance an individual’s energy use, production, or recovery. The form an ergogenic aid may take can be quite varied. Stretching and weight training are physical ergogenic aids. Visualization and hypnosis are mental ergogenic aids. Lighter weight running shoes and better designed golf clubs are mechanical ergogenic aids. But perhaps the most commonly recognized form of ergogenic aids is the dietary supplement.

The availability and use of supplements as ergogenic aids have risen dramatically in the past decade. Some surveys have indicated that approximately 50% of the general population, 76% of college athletes, and 100% of bodybuilders take supplements. New products appear on the market every week.

Being labeled as a “supplement” means that the contents of the product and the claims put forth on the label have not been evaluated by the US Food and Drug Administration. The FDA inspects food and drug products to insure safety and truthful content before they can be marketed to the public. Anything labeled as a “supplement” can be marketed as such without prior FDA approval as provided for under the Dietary Supplement and Health Education Act of 1994. This should be a concern for anyone thinking about taking dietary supplements, as the burden of evaluating any claims made on the label by a manufacturer now falls on the consumer. Many such claims include a statement either that the FDA has not evaluated the claim or that the product is not intended to “diagnose, treat, cure or prevent any disease” (a type of claim that can only legally be made by a drug).

If you decide to take a supplement, there are many ways to go about evaluating its safety and efficacy:

Here is a quick roundup of some of the most popular supplemental ergogenic aids:

Supplement Claimed Action Research
on action
Side Effects Legality


improve concentration, decreases fatigue
and appetite
some support
significant, dangerous banned for
shooting events
anabolic steroids increases strength, lean muscle mass, and motivation supports significant, dangerous illegal
androstenediol same as steroids limited,
unknown banned by Olympics
androstenedione same as steroids refutes,
no benefits
significant banned by Olympics and NCAA
beta-hydroxy-beta-methyl butyrate (HMB) Prevents breakdown and enhances synthesis of protein, increases strength, improves body composition supports long term effects unknown legal
blood doping increase aerobic capacity supports significant, dangerous illegal
branched chain amino acids (BCAA) enhance endurance performance, anti-catabolic (slows down muscle breakdown) mixed, some support for anti-catabolic function appears safe legal
caffeine increases muscle contractility and aerobic endurance, enhances fat metabolism supports mild legal to certain
urine levels
carnitine increases fat metabolism refutes,
no benefits
none legal
chromium increase lean mass refutes,
no benefit unless prior deficiency
safe to 400 mg daily, potentially dangerous above this level legal
coenzyme Q10 enhances function of electron transport chain, improves endurance performance does not support use for athletes appears safe legal
conjugated linoleic acid (CLA) increases response to tissue growth factors, hormones, and cell messengers, increases muscle mass, weight loss, and fat loss limited, animal studies GI distress legal
creatine monohydrate increases muscle energy, short term endurance, strength, and lean
muscle mass
supports, insufficient data on long-term use mild legal
increases endogenous
steroid production
no benefit in
healthy athlete
potentially dangerous banned by Olympics
energy gels quickly supply carbohydrates during endurance exercise supports none, if taken with water legal
ephedrine stimulates CNS, increases energy, delays fatigue, stimulates
weight loss
no benefit potentially dangerous banned by Olympics, FDA and other organizations
fluids increase endurance supports mild legal
human growth hormone increases muscle mass, strength and power, decrease fat mass supports causes enlargement of organs and increases risk of chronic disease banned by world anti-doping agency
leucine decreases muscle breakdown,
spares muscle
glycogen stores
no ergogenic effect
none legal
medium chain triglycerides (MCT) increases energy and muscle cell mass, decrease fat mass, delay fatigue limited intestinal cramping and diarrhea legal
multivitamins increase energy, endurance and aerobic capacity, enhance recovery no benefit unless preexisting deficiency none at RDA,
some toxicities
at high doses
phosphates increase ATP production,
energy and
muscle endurance
limited support mild at
high doses
protein optimizes muscular growth and repair supports,
increased need for
protein with activity
none unless underlying
medical condition
sports drinks increases endurance performance, supply fluid, carbohydrate, and electrolytes supports none legal
zinc increases physical endurance, mental alertness, concentration, free testosterone limited none if taken in recommended dosages legal

Creatine is an amino acid in the skeletal muscle, as well as the liver, pancreas, and kidneys. Supplemental creatine is a popular ergogenic aid, but its benefits are limited. Research has shown creatine to be effective in increasing muscle strength and power during brief, high intensity exercise lasting about one minute or less (such as sprinting and weight lifting). It is believed to work by improving ATP metabolism. Creatine will not benefit endurance athletes. A common side effect is weight gain, which can make athletes feel sluggish. Other reported side effects include diarrhea, muscle cramps, and dehydration. For the most part, however, creatine is considered safe when taken in recommended dosages. Athletes often take creatine in phases. During the loading phase, athletes consume 20-25 grams (in 5 gram increments) per day for 4-7 days. During the maintenance phase, 2-5 grams per day are consumed. Creatine can be obtained through animal foods, such as meat and fish, but in amounts less than 2 grams. Creatine may be slightly more effective when combined with glucose; thus it is frequently sold in combination with carbohydrate. Individual responsiveness to creatine may vary. Vegetarians, who may consume little creatine in the diet, may experience a more pronounced response to creatine supplementation than non-vegetarians.

American Council for Science and Health Web site, search for the topic or click on the nutrition/lifestyle link The Physician and Sportsmedicine Web site, search for nutrition/lifestyle Gatorade Sports Science Institute Web site, search for nutrition/lifestyle Consumer Lab Web site, search for nutrition/lifestyle

USDA Food Surveys Research Group. Supplementary data tables USDA’s 1994-1996 continuing survey of food intakes by individuals. 1999; Table set 12:33.
Sobal J, Marquart LF. Vitamin/mineral supplement use among athletes: a review of the literature. Int. J Sports Nutr. 1994; 4:320-34.
US Food and Drug Administration Web site, search for dietary supplements
Streich, Cynthia MS. Nutritional Ergogenic Aids.
University of Wisconsin Hospital and Clinic Web site
Ahrendt, Dale M, MD. Ergogenic Aids: Counseling the Athlete. American Family Physician 2001; v 63:913-22.
Supplement Watch Web site
Cioca, M. (2005). “Medication and Supplement Use by Athletes.” Clinical Sports Med 24, 719-738.
Fink HH, Burgoon LA, Mikesky AE. Practical Applications in Sports Nutrition. Sudbury, MA: Jones and Bartlett Publishers, 2006.
Dhar R. et al. Cardiovascular toxicities of performance-enhancing substances in sports. Mayo Clinic Proceedings. 2005;80(10):1307-1315. Applegate, Liz. Eat Smart, Play Hard. Rodale, 2001.
Kundrat, Susan. 101 Sports Nutrition Tips. Coaches Choice, 2005.

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