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Creatine, How Safe Is It?

Creatine, How Safe Is It?

Due to severe and sometimes irreversible side effects to anabolic steroids, athletes are constantly looking for a supplement to boost their performance. Bodybuilders consider creatine as the most effective supplement to increase muscle mass. There has been concern among sports medicine specialists that creatine has kidney adverse effects and that long-term safety is not known.


In the early 1800s, creatine was identified in meat extract. One hundred years later, in 1923, rat studies showed improved performance with creatine. In 1930, creatine's role in muscle contraction was elaborated.

Human studies did not begin until 1981. Some patients taking creatine for eye problems reported increased strength. In 1992, Harris reported that 4-6 doses of 5 grams of creatine for 10 days significantly increased total creatine content of the quadriceps muscle.


Muscle contraction depends on adenosine triphosphate (ATP). Creatine is used to replenish ATP. During brief, intense exercise, maximal effort results in rapid depletion of creatine phosphate. Inability of creatine phosphate to maintain a high level of ATP results in fatigue.

Creatine is an amino acid; however, unlike other amino acids, it is not incorporated into proteins. More than 95% of total creatine is stored in skeletal muscles. Two-third of it is phosphorylated as creatine phosphate.

A 180 lb man has about 120 grams of total creatine in his body. One to two grams of creatine is lost daily in urine as the breakdown product creatinine.

A typical diet which includes meat and fish supplies 1-2 g of creatine per day. The rest is synthesized by our body.

Total creatine can be increased by 20% with oral supplementation. Five grams total in 4 divided daily doses for 5 days can rapidly increase muscle creatine. One to two g supplementation daily after that will maintain the increased level of muscle creatine. When you stop the supplement, the increased levels of creatine in your muscle decreases slowly over 30 days to the presupplement baseline.

There is an upper limit to creatine storage in muscles. Vegetarians have smaller total creatine pool. It is felt hat creatine supplement can help increase their creatine storage in muscles. On the other hand, 20-30% of individuals will not respond to creatine supplements.


There are more than 2 dozen studies. Some have conflicting conclusions. Creatine does not appear to improve aerobic fitness. Most of the studies tend to show improvement in performance during maximal intermittent exercise. It is important to note that not all studies have shown this positive effect.

Side Effects

The published studies did not report any serious side effects. These studies lasted only about 1 week and the subjects were young healthy athletes.

The Association of Professional Team Physicians has cautioned that creatine can cause dehydration, electrolyte abnormalities and cramps. The FDA is following the reported cases of adverse side effects.

Weight gain of 2-5 lbs is expected with creatine use. This is caused by water retention.

The long-term consequences of doses greater that 1 g daily are not known.

Drug Interactions

Beware of taking creatine when taking high doses of anti-inflammatory drugs such as Motrin, Naprosyn and Alleve. The ulcer drug Tagamet should not be taken with creatine. Ask your doctor if creatine is dangerous with any of the drugs you are currently taking.


Creatine supplements are available as pills, liquid or powder. The powder form is the most common and is usually mixed 4 times daily in a full glass of orange or grape juice.

Most adult athletes with normal kidney function can take 5 grams in 4 daily divided doses for 5 days, then 2 grams per day.

A 90-day supply can cost you 15-40 dollars. Some companies add carbohydrates to the supplement, which significantly increases the cost. Green’s study in 1996 stated that Dextrose can increase skeletal muscle creatine accumulation.


  • Creatine can increase muscle mass and decrease fatigability in 80% of individuals.
  • It appears to give the most benefit in high intensity intermittent activities such as Football, soccer, basketball, volleyball, weightlifting, hockey and wrestling. These are sports that require bursts of energy.
  • No benefit for aerobic exercising (running, swimming).
  • The casual athlete will not notice much improvement.
  • Twenty to thirty percent of people do not respond to creatine supplementation due to high baseline creatine levels.
  • Do not take Creatine if you have kidney malfunction or are younger than 16 years.
  • Not FDA regulated.
  • Chronic use greater that 1-2 grams per day is not recommended until long term safety is known.
  • The American Academy of Orthopaedic Surgeons
  • American Institute of Ultrasound in Medicine
  • aana
  • American Medical Association
  • Tulsa County Medical Society
  • The University of Tulsa