Creatine Supplement for Fitness - Is It Safe?

Can Creatine Work for You?

Creatine tablets
Creatine in tablet form.. Hugh Threlfall/Getty Images

One of the most popular supplements for sports and fitness performance is creatine. But popularity isn't a verdict on whether it does what you want it to do or that it is safe for everyone to use. Let's look at creatine, what it is supposed to do for you, how to take it safely, and the common and uncommon side effects.

What is Creatine?

Creatine is a naturally occurring substance –- an amino acid –- and it is found in meats and fish.

However, most creatine is made in the body by the liver. Creatine should not be confused with “creatinine,” a product of creatine and protein metabolism, an excess of which may indicate poor kidney function.

Creatine is essential for the production of the fundamental energy unit ATP (adenosine triphosphate). If you don’t produce ATP, the body stops functioning, while deficiencies of creatine production result in decreased muscle function. You can probably see that for athletes and fitness enthusiasts, creatine levels in the body are important.

Manufactured creatine in the form of creatine monohydrate can be absorbed from oral supplements and seems to be treated by the body pretty much like natural creatine.

How Could Creatine Help in Fitness and Sports?

Fuel for muscles
Maximizing the muscle stores of creatine seems to enhance the performance of the short, high-intensity energy system called the ATP and phosphocreatine system, which is used in shorter exercise bouts up to about 20 seconds.

Supplemental creatine may provide a reservoir of creatine that is available for replenishing ATP during repeated short training intervals. Weight lifting repetitions and sets mostly fit into this category.

In fact, most studies show that creatine is most effective for exercise bouts or events that last less than 30 seconds.

Diminished benefits may be available in exercise lasting from 30 seconds to 3 minutes.

Strength and bulk development
Second, creatine may bulk up muscle size and improve strength. Water accumulation in muscle appears to account for some of this bulk and weight gain. Clearly this is of great interest to bodybuilders and strength trainers, but creatine has also been found to improve muscle function in the elderly and in individuals suffering from certain muscle diseases.

Combining the attributes of size and strength with increased athletic power has made creatine a hot supplement for power sports such as football, baseball, track and field, the big men in basketball and anything else where speed and strength are advantageous.

Creatine has most proven benefits for explosive events like sprinting, jumping and weight lifting. Much of these benefits may result from creatine supplementation providing the capacity to train harder and more often. Creatine has not shown to be beneficial for less intense endurance sports such as marathon running or cycle road racing.

Will it work for you?
It’s important to know that not everyone responds to creatine supplementation. Some sports medicine authorities have estimated that 30% of users see no beneficial effect.

Is Creatine Safe?

Kidney and liver toxicity
In the last 10 years, creatine has been used extensively, even if mostly by men, and studied substantially, if not comprehensively. Few side effects have been consistently reported from short-term use with approved quantities. The likelihood of it being a health hazard for long-time, regular users of creatine is still unknown. Kidney and liver function in creatine users has been studied as a potential target of toxicity, but no consequential effects have been shown to occur at recommended doses in controlled trials. However, case reports and animal studies suggest possible adverse effects on the kidney.

In one Dutch study with 175 subjects, half were given 10 grams of creatine each day and the other half, randomly selected, were given a dummy supplement with no creatine for 310 days. No kidney or liver abnormalities were detected.

It would be sensible not to take creatine if kidney disease is present or suspected. Some overweight people have chronic, undiagnosed kidney disease, so using creatine in a weight loss or bodybuilding program would probably be unwise for these people.

Muscle cramps, water retention and swollen limbs
In the same Dutch study, swollen limbs were seen more often in the creatine takers, and three individuals in the creatine group had to withdraw because of nausea. The swollen limbs were attributed to water retention, which is one effect that seems to be established both scientifically and by word of mouth among users. Whether this is an adverse effect is probably best left to each individual's assessment. In another sense it may reflect muscle enlargement (hypertrophy), or more seriously, muscle compartment abnormality.

Muscle compartment syndrome is a condition which often affects the lower legs although other areas of the body can be affected. The muscles swell and fill the "compartment" in which they function, producing abnormal pressure that can result in pain and, at worst, damage to nerves and small blood vessels.

Complaints of muscle cramping seem to be widespread, if not epidemic, in the athletic, sports and weight training communities and this may be as a result of excessive water retention and muscle swelling at higher “loading” doses. These high "starter" doses are not necessary as you will see in the following discussion on how much to take.

Serious Reactions to Creatine Supplements

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 Creatine 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).

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