Creatine Side Effects Update

This creatine side effects update covers sources of creatine in food,effective supplementation and study results of creatines effectiveness. Over the last decade, thousands of articles have been written about creatine side effects in scientific journals, magazines, newspapers, and on the Internet. The reason for this interest is that creatine supplements have proven to be one of the most effective methods available to increase strength, power, and muscle mass. Moreover, a number of potential therapeutic creatine benefits have been suggested for various patient populations. Despite this impressive body of research, concerns have been raised about the safety of creatine side effects and ethics of athletes taking performance-enhancing nutritional supplements. While a number of very good reviews have been published about creatine side effects in the scientific literature, a significant amount of misinformation has been written about creatine side effects, particularly in the popular media. Additionally, several nutritional supplement companies have attempted to gain market share by perpetuating some of these creatine side effect myths. The result is that people are often confused about the potential creatine benefits and risks of creatine supplements. The purpose of this article is to provide an update on the state of the science regarding creatine side effects as well as to answer some common questions about creatine supplements so that you can make an informed decision about whether to use creatine or not.

What is Creatine Monohydrate?

Creatine monohydrate is a naturally occurring amino acid-like compound that is found primarily in the muscle (95%). There is also a small amount of creatine in the brain and testes. About two thirds of creatine found in the muscle is stored as phosphocreatine (PCr) while the remaining amount of creatine is stored as free creatine. The total creatine pool (PC + free creatine) in the muscle averages about 120 grams for a normal sized person. However, the body has the capacity to store up to 160 grams of creatine under certain conditions.

Sources of Creatine Monohydrate:

The body breaks down 1 to 2% of the creatine pool per day (about 2 grams) into creatinine in the muscle. The creatinine is then excreted in urine. The body can replenish depleted creatine in two ways. First, about half of your daily creatine needs can be obtained from your normal diet by eating foods that contain creatine. For example, there is about 1 to 2 grams of creatine in a pound of uncooked beef and salmon. The remaining amount of creatine is synthesized from the amino acids glycine, arginine, and methionine. Normal dietary intake of creatine from food and creatine synthesis typically maintains creatine levels at about 120 grams for a normal size individual. Vegetarians have been reported to have lower than normal muscle creatine stores. Additionally, some people have been found to have creatine synthesis deficiencies and therefore must depend on dietary availability of creatine to maintain normal muscle concentrations.

Creatine Supplement Protocols:

The most common way to increase muscle creatine stores is to "load" creatine by taking 5 grams of creatine monoohydrate four times per day for 5 to 7 days. Studies show that this protocol can increase muscle creatine and PC by 10 to 40%. Once muscle creatine stores are saturated, studies indicate that you only need to take 3 to 5 grams of creatine monohydrate per day in order to maintain elevated creatine stores. An alternative supplementation protocol is to ingest 3 grams/day of creatine monohydrate for 28-days. Studies show that this method can increase muscle concentrations of creatine as effectively as creatine monohydrate loading techniques. However, this method would only result in a gradual increase in muscle creatine content compared to the more rapid loading method. Some athletes also cycle on and off creatine by taking loading doses of creatine monohydrate for 3 to 5 days every 3 to 4 weeks during training. Theoretically, since it takes 4 to 6 weeks for elevated creatine stores to return to baseline, this protocol would be effective in increasing and maintaining elevated creatine stores over time.

Creatine Side Effects from Supplementation on Muscle Creatine Stores:

Numerous studies indicate that dietary supplementation of creatine monohydrate increases muscle creatine and phosphocreatine (PC) content by 10 to 40%. In simple terms, one can think of the normal creatine content of the muscle (about 120 grams) as being a gas tank that is 3/4 full. Creatine supplementation typically allows an individual to fill up their creatine storage tank up to 150 to 160 grams (i.e., 20 to 30%). It should be noted that the amount of creatine retained in the muscle following creatine supplementation depends on the amount of creatine in the muscle before supplementation. Individuals with low creatine content in muscle prior to supplementation may increase creatine stores by 20 to 40% while individuals with relatively high creatine levels before supplementation may only experience a 10 to 20% increase in muscle creatine content. Performance changes in response to creatine supplementation have been correlated with the magnitude of increase in muscle creatine levels. Once creatine levels are elevated and an individual stops taking creatine, studies indicate it may take 4 to 6 weeks before creatine levels return to baseline. There is no evidence that muscle creatine levels fall below baseline after cessation of creatine supplementation, which might suggest a long-term suppression of endogenous creatine synthesis.

Theoretical Benefits of Creatine Supplementation

Increasing muscle availability of creatine and PC can affect exercise and training adaptations in several ways. First, increasing the availability of PC in the muscle may help maintain availability of energy during high intensity exercise, like sprinting and weightlifting. Second, increasing the availability of PC may help speed recovery between sprints and/or bouts of intense exercise. These adaptations would allow an athlete to do more work over a series of sprints and/or sets of exercise theoretically leading to greater gains in strength, muscle mass, and/or performance over time. For this reason, creatine supplementation has primarily been recommended as an ergogenic aid for power/strength athletes. However, recent research indicates that endurance athletes may also benefit from creatine supplementation. In this regard, studies indicate creatine side effects of loading prior to carbohydrate loading promotes greater glycogen retention. Additionally, studies indicate that ingesting creatine with carbohydrate during carbohydrate loading promotes greater creatine and glycogen retention. Theoretically, this may improve glycogen availability for endurance athletes. Creatine side effects have also been shown to improve repetitive sprint performance. Since endurance athletes employ interval training techniques in an attempt to improve speed and anaerobic threshold, creatine supplementation during training may improve interval training adaptations leading to improved performance. Finally, studies also indicate that creatine side effects can help maintain body weight and muscle mass during training. Since many endurance athletes have difficulty maintaining body mass during training, creatine supplementation may help maintain optimal body composition.

Creatine Side Effects on Exercise Performance or Training Adaptations

There have been more than one thousand articles published in the peer-reviewed scientific literature on creatine supplementation. Slightly over half of these studies have evaluated the effects of creatine supplementation on exercise performance. The majority of these studies (about 70%) indicate that creatine supplementation promotes a statistically significant improvement in exercise capacity. This means that 95 times out of 100, if you take creatine as described in the study, you will experience an improvement in exercise performance. The average gain in performance from these studies typically ranges between 10 to 15%. For example, short-term creatine supplementation has been reported to improve maximal power/strength (5-15%), work performed during sets of maximal-effort muscle contractions (5-15%), single-effort sprint performance (1-5%), and work performed during repetitive sprint performance (5-15%). Long-term creatine supplementation appears to enhance the quality of training generally leading to 5 to 15% greater gains in strength and performance. Nearly all studies indicate that creatine supplementation increases body mass by about 1 to 2 kg in the first week of loading. In training studies, subjects taking creatine typically gain twice as much body mass and/or fat free mass (i.e., an extra 2 to 4 pounds of muscle mass during 4 to 12 weeks of training) than subjects taking a placebo. No study has reported that creatine supplementation significantly impairs exercise capacity. Although all studies do not report significant results, the preponderance of scientific evidence indicates that creatine supplementation appears to be an effective nutritional ergogenic aid for a variety of exercise tasks in a number of athletic and clinical populations. The following highlights some of the recent research that has evaluated the effects of short and long-term creatine supplementation on exercise performance and/or training adaptations.

Maximize positive creatine side effects with proper exercise.