Articles

Creatine

Introduction

Creatine plays an important role in the production of energy and in the process of building muscle tissue. While creatine can be produced in the body from certain amino acids, many athletes are using creatine as a performance-enhancing agent. (1) , (2) Studies suggest creatine may enhance the performance of high-intensity, short-duration exercise. However, it is not useful in endurance sports. (3)

Creatine is found in the body in muscle, brain, and blood. However, most creatine in the body is stored in muscles. Scientists think its potential for increasing energy comes from its ability to help the body increase the efficiency with which cells use energy.

While there are many in the medical community who are skeptical about creatine’s benefits, it is currently a legal method of enhancing performance and increasing body mass. Some studies support the claim that creatine is safe and effective. At the same time, there are other studies with less promising results. In fact, French authorities are so concerned about the safety of creatine that they have made the sale of creatine supplements illegal. Furthermore, in January 2001, France's Food Safety Agency posted warning statements regarding the use of creatine on the Agency’s WEB site. (4)

Part of the concern is that creatine use is so widespread among athletes at all levels. Surveys show substantial numbers of high school athletes are using creatine supplementation. In one survey 16% of the athletes from 11 high schools in Tennessee admitted to using creatine. (5) Another survey reported 44% of the high school athletes from a single school in a suburb of New York City using creatine. (6) Experts strongly recommend against the use of creatine among adolescent athletes until more is known about its safety.

Animal protein is the best source of dietary creatine.

Dosage Info

Dosage Range

2 to 20 grams daily.

Most Common Dosage

Although there is no definitive guide on how much creatine to take, many experts suggest that larger amounts should be taken as a "loading phase" during the first week of supplementation when the body is most responsive. This can reportedly create substantial gains in muscle size, strength, and performance in as little as one week. A typical loading dose is 5 grams taken four times a day for one week. After muscles are saturated with creatine, a maintenance dose of 5 to 10 grams a day can be consumed. It is generally recommended that creatine be taken 60 to 90 minutes before and/or after exercising.

Dosage Forms

Powder, capsules, tablets, liquid, gum, or effervescent powder form. Stabilization of liquid creatine is still suspect since it degrades to creatinine in this form.

Reported Uses

As mentioned, studies suggest that creatine can help improve exercise performance in high-intensity, short duration forms of exertion or competition. These studies have measured more lean muscle mass and increased weight-lifting, jumping, and sprinting performance. (7) , (8) , (9) Studies further suggest that women may also benefit from creatine supplementation. (10)

In addition to offering potential benefits for athletes, creatine may have some clinical applications for treating health disorders. One study suggested that creatine may support motor performance and increase survival times for people with amyotrophic lateral sclerosis (ALS), commonly referred to as Lou Gehrig’s disease. (11) Creatine may also support muscle health and help maintain body weight in other types of neuromuscular disorders (12) as well as McArdle disease, a muscular disorder where creatine supplementation reduced muscle complaints and improved muscle function. (13)

Congestive heart failure patients have also benefited from creatine use. One human study using 20 grams daily for 10 days showed improvements in both strength and endurance. (14) In another human study, patients with congestive heart failure used 20 grams of creatine daily for 5 days and showed greater muscle endurance and improved skeletal muscle function when exerted. (15)

Toxicities & Precautions

Introduction

[span class=alert]Be sure to tell your pharmacist, doctor, or other health care providers about any dietary supplements you are taking. There may be a potential for interactions or side effects.[/span]

General

Some experts feel that the long-term safety of high-dose creatine use has not been properly evaluated.

Large doses of creatine coupled with intense exercise can lead to kidney dysfunction. (16) , (17) Increased fluid intake will help dilute the contents and facilitate elimination.

Another potential problem associated with creatine use is related to possible contaminants that are produced during the manufacturing of the product. Contaminants such as dicyandiamide, dihydrotriazine, and creatinine may be found in the final product. (18) Be advised of this and realize that consumption of large doses of creatine may also increase the amount of contaminants consumed. Some companies state on their labels that their creatine products are guaranteed to be free of these contaminants. Until further toxicity studies are done, the effects of these contaminants are not fully understood.

An additional concern is that in products produced in Europe, amino acids that could have originated from bovine sources may have been used in the production of creatine.

Health Conditions

If you have high-blood pressure, talk to your doctor before taking this dietary supplement.

Side Effects

Occasional side effects reported with the use of this dietary supplement include weight gain, cramping, (19) dehydration, diarrhea and dizziness. Doctors recommend limiting a single dose serving to 5 grams to avoid diarrhea. Tell your doctor if these side effects become severe or do not go away.

Pregnancy / Breast Feeding

To date, the medical literature has not reported any adverse effects related to fetal development during pregnancy or to infants who are breast-fed. Yet, little is known about the use of this dietary supplement while pregnant or breast-feeding. Therefore, it is recommended that you inform your healthcare practitioner of any dietary supplements you are using while pregnant or breast-feeding.

Age Limitations

This supplement should not be used in children unless recommended by your physician.

References

  1. View Abstract: Selsby JT, DiSilvestro RA, Devor ST. Mg2+-creatine chelate and a low-dose creatine supplementation regimen improve exercise performance. J Strength Cond Res. May2004;18(2):311-5.
  2. View Abstract: Lehmkuhl M, Malone M, Justice B, et al. The effects of 8 weeks of creatine monohydrate and glutamine supplementation on body composition and performance measures. J Strength Cond Res. Aug2003;17(3):425-38.
  3. View Abstract: Ostojic SM. Creatine supplementation in young soccer players. Int J Sport Nutr Exerc Metab. Feb2004;14(1):95-103.
  4. McDonough M. Associated Press wire report (Paris AP). Jan2001.
  5. View Abstract: Ray TR, Eck JC, Covington LA, et al. Use of oral creatine as an ergogenic aid for increased sports performance: perceptions of adolescent athletes. South Med J. Jun2001;94(6):608-12.
  6. View Abstract: Metzl JD, Small E, Levine SR, Gershel JC. Creatine use among young athletes. Pediatrics. Aug2001;108(2):421-5.
  7. View Abstract: Volek JS, et al. Performance and muscle fiber adaptations to creatine supplementation and heavy resistance training. Med Sci Sports Exerc. Aug1999;31(8):1147-56.
  8. View Abstract: Bosco C, et al. Effect of oral creatine supplementation on jumping and running performance. Int J Sports Med. Jul1997;18(5):369-72.
  9. View Abstract: Preen D, Dawson B, Goodman C, et al. Effect of creatine loading on long-term sprint exercise performance and metabolism. Med Sci Sports Exerc. May2001;33(5):814-21.
  10. View Abstract: Vandenberghe K, et al. Long-term creatine intake is beneficial to muscle performance during resistance training. J Appl Physiol. Dec1997;83(6):2055-63.
  11. View Abstract: Klivenyi P, et al. Neuroprotective effects of creatine in a transgenic animal model of amyotrophic lateral sclerosis. Nat Med. Mar1999;5(3):347-50.
  12. View Abstract: Tarnopolsky M, Martin J. Creatine monohydrate increases strength in patients with neuromuscular disease. Neurology. Mar1999;52(4):854-7.
  13. View Abstract: Vorgerd M, Grehl T, Jager M, et al. Creatine therapy in myophosphorylase deficiency (McArdle disease): a placebo-controlled crossover trial. Arch Neurol. Jul2000;57(7):956-63.
  14. View Abstract: Gordon A, Hultman E, Kaijser L, et al. Creatine supplementation in chronic heart failure increases skeletal muscle creatine phosphate and muscle performance. Cardiovasc Res. Sep1995;30(3):413-8.
  15. View Abstract: Andrews R, Greenhaff P, Curtis S, et al. The effect of dietary creatine supplementation on skeletal muscle metabolism in congestive heart failure. Eur Heart J. Apr1998;19(4):617-22.
  16. View Abstract: Graham AS, Hatton RC. Creatine: a review of efficacy and safety. J Am Pharm Assoc (Wash). Nov1999;39(6):803-10.
  17. View Abstract: Benzi G, Ceci A. Creatine as nutritional supplementation and medicinal product. J Sports Med Phys Fitness. Mar2001;41(1):1-10.
  18. View Abstract: Benzi G, Ceci A. Creatine as nutritional supplementation and medicinal product. J Sports Med Phys Fitness. Mar2001;41(1):1-10.
  19. View Abstract: Benzi G, Ceci A. Creatine as nutritional supplementation and medicinal product. J Sports Med Phys Fitness. Mar2001;41(1):1-10.