Unless you’ve been living in seclusion, you have most likely heard of the nutritional supplement creatine. The use of creatine as a performance enhancer was first popularized after the 1992 Olympic Games in Barcelona, and testimonies by Mark McGuire and many other professional athletes have made creatine use extremely popular in the United States. Creatine use is not limited to the professional or even collegiate athlete, as high school students and even those younger are using it. As I always state, whenever an individual is contemplating the use of a supplement two questions must always be asked; is it safe, and does it work? I will address these questions in their order of importance.
Is creatine safe?
Since the time creatine legally made its way onto the shelves in 1992, its use has been widespread, with literally billions of dollars being spent on these products. Consumers were attracted to creatine with the claims of steroid like gains in muscle mass and strength without the dangers associated with steroid use. Very early on, however, many in the medical community were both skeptical and concerned, as the research concerning it’s safety was very limited. The medical community was concerned that mistakes similar to those involved with steroid use were being made. For example, when steroids first became popular the clinical studies were few in number and few in subject number, thus lacking in clinical significance (we never really had a chance to see if true problems would occur or not). As time went on, those using steroids for performance enhancement became the guinea pigs, (subjects) and the side effects and dangers were finally realized. A similar scenario has occurred with creatine, as those using it have become the guinea pigs, however the outcome is different. The volume of use that has taken place over the past decade is so high that there would be an obvious body count if serious side effects were associated with creatine use. A noticeable pattern of side effects would have been seen by now if they existed and this has not happened. At this time the only side effect directly associated with creatine ingestion is weight gain (for many this effect is desired). Because the weight gain occurs over a short period of time, it is likely that it is primarily due to water retention. We have shown this to be true in our lab.
There are numerous reports of muscle pulls, muscle cramping, dehydration, gastrointestinal distress, and kidney dysfunction associated with creatine use. However, these are anecdotal claims and many of them based on isolated cases. Obviously single (or even a few) cases do not imply a cause and effect relationship. In fact, a few retrospective studies have been conducted recently, where users of creatine have been surveyed about the occurrence of side effects. The general conclusion from these studies is that creatine is not associated with any side effects beyond weight gain (and this does not always happen). However, I would like to present to you a scenario in which I do see creatine causing a problem. When creatine is ingested it is absorbed into the blood and is eventually taken up by the muscle. It has been shown that when greater amounts of creatine are consumed, the muscle increase occurs faster than if lower amounts are consumed. This is now known as the loading phase of creatine ingestion. Following a certain amount of muscle uptake (everyone is different as far as how much that is) the muscle will not take in any more. When this occurs, supplementation with higher dosage amounts is no longer necessary, as continuing with lower amount will be sufficient. This has become known as the maintenance phase of supplementation. This is why the manufacturers direct the consumer to ingest about 20-25 grams each day for 5-7 days followed by 5 grams each day after that. Once the muscle has reached its limit and will no longer take in more creatine, that is it. It does not matter if the higher dosages are continued for a longer period of time or if the dosages are increased to even greater amounts. The muscle is not going to take it in. When this happens, the blood levels of creatine rise, requiring the kidneys to filter it out and return it to normal. At this point there is a large amount of creatine (which contains nitrogen) being filtered through the kidneys. If water is being retained at the same time, the urine becomes very concentrated. It is possible that this could lead to some type of kidney dysfunction. However, this is a situation of misuse or abuse. The idea that if some is good than more is better definitely does not apply here. So the answer to the first question is; yes it appears to be safe if used correctly.
Does creatine work?
The theory behind creatine use is very similar to carbohydrate loading. With carbohydrate loading, you try to maximize the storage of glycogen (the storage form of glucose in the muscle) to delay fatigue and improve performance. Similarly, if you increase the muscle’s storage of creatine, you can enhance the energy capacity of the muscle (phosphagen energy system) and delay fatigue during high-intensity short-duration activities. This would result in faster sprint times (running, cycling, swimming, rowing, etc.), higher average jumping heights, greater number of repetitions at a given resistance (and a training effect of increased strength), and improved power.
In order to have a chance for performance improvement, you must first experience an increase in muscle creatine levels when the creatine is ingested. A number of studies have shown that the supplementation protocols recommended by manufacturers (loading and maintenance phases) are effective for increasing muscle creatine levels and then maintaining those increases. However, studies have also shown that approximately 30-40% of the people ingesting creatine do not experience a significant increase in muscle creatine levels and, therefore, do not have a chance for performance enhancement (beyond a placebo effect).
Hundreds of studies have been performed investigating the effects of creatine on performance. These measures of performance have included running, cycling, swimming, skating, jumping, pitching, rowing, weight lifting, and many others. The final conclusion – it is basically a coin toss. For every ten studies I find reporting improvements, I can find ten more reporting no improvement. As I mentioned previously, in order to have a chance for improved performance you must first experience an increase in muscle creatine levels, which does not always happen.
Reports of weight gain are a bit more consistent. The question now concerns the source of the weight gain, with protein synthesis and water retention being the more popular theories. Because the weight gain is observed over a short period of time, it cannot be explained by protein synthesis alone. Thus, water retention is a more likely cause. We have observed this effect in our lab as those ingesting creatine experienced a significant increase in body mass and body water volume. However, there is some evidence supporting the theory of increased protein synthesis following increases in muscle creatine (although this has not been measured directly). In fact, the increased cell volume (water retention) appears to be a stimulus for an anabolic response. At this time it is just speculation, so we will just have to wait and see.
There are a number of factors that can effect the potential for performance improvements, such as the type of training and performance testing, training level, diet, and initial creatine levels. For some, improvements will be noted, while for others they will not. So the answer to the second question is; maybe. At least if it is used correctly, the only side effects will be expensive urine and wallet atrophy.
It is important to stress that creatine is a supplement, meaning it should be used in addition to proper training and diet and should not be used as a replacement for either one (or any part of either one). Proper training, diet, and dedication is key, as there are no shortcuts.