creatine side effects | creatine facts
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Creatine side effects: are we to believe the latest scare stories about creatine?
Lately, creatine monohydrate has been getting a bad press. The recent maligning of this popular sports supplement has been a surprise to many athletes and coaches, because it is known with relative certainty that creatine can indeed improve muscular strength in a variety of different athletes, including football players, weightlifters, swimmers, and cyclists. We also know that creatine supplementation can improve the quality of runners' interval workouts ('Creatine Propels British Athletes to Olympic Gold Medals: Is Creatine the One True Ergogenic Aid?' Running Research News, vol. 9(1), pp. 1-5, 1993).
The heart of the bad press concerns creatine side effects, which are alleged to include muscle, tendon, and ligament strains. In theory, creatine can improve the explosive energy production of muscle cells without actually fortifying the mechanical strength of muscles and their attached tendons, as well as ligaments holding together the joints across which muscles and tendons act. As a result, the unusually powerful contractions produced in creatine-loaded muscles might literally tear apart the not-yet-reinforced muscle cells, as well as their associated connective tissues, at least in theory.
It's a fairly logical contention, and anecdotally there do seem to be numerous reports of injury in creatine-filled performers. However, we should point out that no carefully controlled scientific study has actually linked creatine supplementation with a heightened risk of muscle or connective-tissue damage. In addition, linking two events together, in this case increases in creatine loading with apparent increases in injuries, does not mean that one causes the other. In the United States, for example, beer consumption by high-school seniors sometimes rises in years in which college-entrance-exam scores also soar, but it would be hard to argue that lager-loading is making students brighter (a stronger argument would be that good test results precipitate celebratory imbibing).
Another concern about creatine side effects has to do with the potential adverse health effects of long-term use of the supplement. Expressing this anxiety, one of our subscribers recently wrote to say, 'I would really like to see a 12-month (or longer) study of creatine's effects on the human body. Hopefully, it would be conducted by someone who is not trying to sell creatine. If you could find a study like that, I would start supplementing with creatine myself, because I do believe it works for most people'.
The writer of this letter was apparently referring to the fact that most creatine studies have lasted only eight to 12 weeks, hardly enough time to unearth any long-term negative side effects. Indeed, some scientists have expressed concern that long-term supplementation with creatine might permanently shut down endogenous creatine synthesis in the liver (creatine is a natural compound which your own body manufactures). Of course, that would lead to problems if creatine supplementation were discontinued; a person would steadily become creatine-depleted, leading to dramatic increases in fatigue.
However, the truth is that creatine intake in humans has been studied over fairly long time periods. In one investigation, human subjects ingested a 'maintenance dose' of about 1.5 grams of creatine per day for 12 months in hopes of stabilizing an eye disease called gyrate atrophy of the choroid retina. In this disease, patients suffer from a gradual reduction of the visual field. The disorder is also associated with an atrophy of Type II (fast-twitch) muscle fibres. The given dosage of creatine did indeed stabilize the eye disorder ('Supplementary Creatine as a Treatment for Gyrate Atrophy of the Choroid Retina,' New England Journal of Medicine, vol. 304, pp. 867-870, 1981).
In follow-up work, which actually continued for a total of five years, it was noted that creatine also increased the diameter of muscle fibres in the subjects' thighs. When some of the patients stopped taking creatine, the muscle cells regressed to their previous, smaller size ('Gyrate Atrophy of the Choroid and Retina: A Five-Year Follow-Up of Creatine Supplementation, Opthalmology, vol. 92, pp. 1719-1727, 1985).
Fortunately, research also indicates that the enzymes necessary for creating creatine do return to normal once supplementation is stopped (Journal of Biological Chemistry, vol. 236, pp. 493-498, 1960). Thus, there's no evidence that long-term supplementation might increase the risk of creatine depletion.
Based on the available research, the quantity of creatine used by athletes for maintenance dosing (about 2 grams per day) appears to be very safe. Less is known about the effects of larger, loading doses (20 grams per day); the only known adverse effect is an increase in body weight. To minimize risk and still super-fill your muscles' creatine stores, you should not take the 20-gram dose for more than four to five days at a time; such loading will keep muscle-creatine concentrations very high for about five weeks or so. It makes very little sense to take more than that.
What about the issue of creatine's possible encouragement of muscle and connective-tissue damage, as well as cramping? We'll keep you posted on that as more research becomes available.
A footnote on glycerol
A few months ago you may have read that the International Olympic Committee had placed glycerol on its banned-substances list. The IOC's decision was based in part on the mistaken notion that glycerol acted as a diuretic, 'dragging water' out of the kidneys and enhancing urinary output. Wisely, that decision has now been reversed. Glycerol is still illegal if given intravenously, but it may be taken orally without risk of punishment.
The IOC's decision was good news to Internutria Sports, a U.S.-based company which makes a glycerol-containing sports drink called ProHydrator. The company actually halted production of ProHydrator in May of this year, because it did not want athletes to get into trouble with the IOC. ProHydrator should be available to athletes very soon.
Owen Anderson
creatine side effects
It's a fairly logical contention, and anecdotally there do seem to be numerous reports of injury in creatine-filled performers. However, we should point out that no carefully controlled scientific study has actually linked creatine supplementation with a heightened risk of muscle or connective-tissue damage. In addition, linking two events together, in this case increases in creatine loading with apparent increases in injuries, does not mean that one causes the other. In the United States, for example, beer consumption by high-school seniors sometimes rises in years in which college-entrance-exam scores also soar, but it would be hard to argue that lager-loading is making students brighter (a stronger argument would be that good test results precipitate celebratory imbibing).
Another concern about creatine side effects has to do with the potential adverse health effects of long-term use of the supplement. Expressing this anxiety, one of our subscribers recently wrote to say, 'I would really like to see a 12-month (or longer) study of creatine's effects on the human body. Hopefully, it would be conducted by someone who is not trying to sell creatine. If you could find a study like that, I would start supplementing with creatine myself, because I do believe it works for most people'.
The writer of this letter was apparently referring to the fact that most creatine studies have lasted only eight to 12 weeks, hardly enough time to unearth any long-term negative side effects. Indeed, some scientists have expressed concern that long-term supplementation with creatine might permanently shut down endogenous creatine synthesis in the liver (creatine is a natural compound which your own body manufactures). Of course, that would lead to problems if creatine supplementation were discontinued; a person would steadily become creatine-depleted, leading to dramatic increases in fatigue.
However, the truth is that creatine intake in humans has been studied over fairly long time periods. In one investigation, human subjects ingested a 'maintenance dose' of about 1.5 grams of creatine per day for 12 months in hopes of stabilizing an eye disease called gyrate atrophy of the choroid retina. In this disease, patients suffer from a gradual reduction of the visual field. The disorder is also associated with an atrophy of Type II (fast-twitch) muscle fibres. The given dosage of creatine did indeed stabilize the eye disorder ('Supplementary Creatine as a Treatment for Gyrate Atrophy of the Choroid Retina,' New England Journal of Medicine, vol. 304, pp. 867-870, 1981).
Fortunately, research also indicates that the enzymes necessary for creating creatine do return to normal once supplementation is stopped (Journal of Biological Chemistry, vol. 236, pp. 493-498, 1960). Thus, there's no evidence that long-term supplementation might increase the risk of creatine depletion.
Based on the available research, the quantity of creatine used by athletes for maintenance dosing (about 2 grams per day) appears to be very safe. Less is known about the effects of larger, loading doses (20 grams per day); the only known adverse effect is an increase in body weight. To minimize risk and still super-fill your muscles' creatine stores, you should not take the 20-gram dose for more than four to five days at a time; such loading will keep muscle-creatine concentrations very high for about five weeks or so. It makes very little sense to take more than that.
What about the issue of creatine's possible encouragement of muscle and connective-tissue damage, as well as cramping? We'll keep you posted on that as more research becomes available.
A footnote on glycerol
A few months ago you may have read that the International Olympic Committee had placed glycerol on its banned-substances list. The IOC's decision was based in part on the mistaken notion that glycerol acted as a diuretic, 'dragging water' out of the kidneys and enhancing urinary output. Wisely, that decision has now been reversed. Glycerol is still illegal if given intravenously, but it may be taken orally without risk of punishment.
The IOC's decision was good news to Internutria Sports, a U.S.-based company which makes a glycerol-containing sports drink called ProHydrator. The company actually halted production of ProHydrator in May of this year, because it did not want athletes to get into trouble with the IOC. ProHydrator should be available to athletes very soon.
Owen Anderson
creatine side effects
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