Serious adverse reactions to creatine are rare in medical case reports. Even so, it's worth watching for them.
Muscle effects
Of a more serious nature are a few reports of the potential for creatine to cause muscle compartment syndrome and other relatively serious muscle conditions. In one case report, surgeons reported sudden kidney failure and muscle breakdown during knee surgery in a footballer who was taking 10 grams/day of a creatine supplement. They suggested the patient's use of creatine increased the risk of muscle injury due to blood vessel blockage from a tourniquet application during surgery.
Considering that muscle compartment abnormalities may be worsened in hot weather and inadequate fluid intake, this is one element of risk that may be controlled to some extent by judicious water and sports drink intake before, during and after vigorous exercise.
Abnormal heart rhythms
In one scientific report, a 30-year-old creatine supplement user reported to a hospital emergency department with heart arrhythmia, which the medical staff suggested was rare in a young person without any other underlying heart condition. They reported knowledge of other cases of arrhythmia suspected to be associated with creatine taking.
Creatine and Adolescents and Students
Although the risks of supplement taking described above apply to adolescents as well as adults, they especially apply to high-school and college athletes. These are people who may be still growing and developing and may also be under pressure to perform. Consequently, they may try products from illicit sources who efficacy and safety cannot be guaranteed.The American College of Sports Medicine recommends that creatine not be used by anyone younger than 18 years and that coaches and trainers should not recommend or supply creatine or other supplements to student athletes.
How Much Should I Take?
Two dosing methods exist for taking creatine.- Rapid loading method. Take 20 grams of creatine daily, in 4 doses of 5 grams, for 4 to 5 days -- then after that, 2 to 3 grams each day or cycle your intake.
- Gradual method. Take 2 to 3 grams of creatine daily for 30 days and continue or cycle your intake.
The gradual method takes about 30 days to saturate the muscles in the same way as loading over 5 days. You benefit from not being exposed to the higher amounts that possibly could cause you to react badly. "Cycling" means you take a break from creatine supplementation -- say one month in every two, or two weeks in every four. Various opinions abound about cycling but little scientific information exists. One possible reason to cycle is to allow your body to return to normal. Taking supplementary creatine could cause your body to shut down its natural production of creatine in the same way that taking anabolic steroids causes the body to turn off production of testosterone.
If you decide to take creatine, I recommend the 2-gram/day method, which seems to be as effective as the loading method and which probably also provides you with a margin of safety from adverse effects.
Creatine is popular and reasonably safe to use in recommended quantities and from reputable suppliers. It seems to provide some advantage, mostly in weight training and bodybuilding sports. However, I'm not convinced it is necessary and may even be disadvantageous for athletes who require speed, agility and optimum mobility.
Sources:
Bemben MG, Lamont HS. Creatine supplementation and exercise performance: recent findings. Sports Med. 2005;35(2):107-25. Review.
Rawson ES, Volek JS. Effects of creatine supplementation and resistance training on muscle strength and weightlifting performance.
J Strength Cond Res. 2003 Nov;17(4):822-31. Review.
Pline KA, Smith CL. The effect of creatine intake on renal function. Ann Pharmacother. 2005 Jun;39(6):1093-6. Review.
Groeneveld GJ, Beijer C, Veldink JH, Kalmijn S, Wokke JH, van den Berg LH. Few adverse effects of long-term creatine supplementation in a placebo-controlled trial. Int J Sports Med. 2005 May;26(4):307-13.
Hile AM, Anderson JM, Fiala KA, Stevenson JH, Casa DJ, Maresh CM. Creatine supplementation and anterior compartment pressure during exercise in the heat in dehydrated men. J Athl Train. 2006 Jan-Mar;4 (1):30-5.
Sheth NP, Sennett B, Berns JS. Rhabdomyolysis and acute renal failure following arthroscopic knee surgery in a college football player taking creatine supplements. Clin Nephrol. 2006 Feb;65(2):134-7.
Kammer RT. Lone atrial fibrillation associated with creatine monohydrate supplementation. Pharmacotherapy. 2005 May;25(5):762-4.
Koshy KM, Griswold E. et al. Interstitial nephritis in a patient taking creatine [letter] N Engl J Med. 1999; 340:814.
Edmunds JW, Jayapalan S. et al. Creatine supplementation increases renal disease progression in Han:SPRD-cy rats. Am J Kidney Dis. 2001 Jan;37(1):73-78).
