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Eagle
Scientific Name: Creatine
Other Names: Creatine Citrate, Creatine Monohydrate, Creatine Phosphate
Who is this for?
Uses
After several prominent athletes acknowledged using it in the past few years, creatine is best known for possibly improving athletic performance. Although multiple studies have been conducted to assess the effect of creatine on exercise potential, results are mostly inconclusive. While muscles may become bigger when creatine is taken, the gain in size may be due mainly to more water being held in the cells of muscle tissue. Additionally, it is important to note that many of the studies were done in clinics or laboratory settings that do not necessarily duplicate conditions at actual athletic events. Most of the studies tested small groups of young, trained athletes who took many different doses and forms of creatine. In general, results of the studies show that creatine supplementation may offer younger individuals a benefit for improving repeated, intensive spurts of effort such as weight-lifting. Less apparent improvement or no effects occurred for more sustained exercise such as swimming laps. Based on the responses of some individuals, taking creatine may actually decrease the ability to maintain prolonged exercise. Results among older individuals were inconclusive with small benefits seen in some studies, but no exercise improvement in others.
Since the potential muscle-enhancing effect of creatine supplementation may affect all muscles in the body, it has also been studied for treating heart conditions and muscular disorders such as muscular dystrophy. Several small studies of individuals with heart failure have had mixed results. In some studies, creatine has appeared to have a direct effect on the heart, causing it to beat more forcefully. Other studies found no effect on the heart itself, although an increase in overall muscle strength was seen in many of the individuals receiving creatine supplements. Creatine may have been more beneficial for improving heart function when it was injected into a vein than when it was taken orally. For individuals with muscle-weakening conditions, results of studies are also inconsistent. Animal studies show that creatine may lessen the effects of Huntington's disease, a hereditary degenerative disorder of brain tissue. In studies of individuals with a rare genetic condition known as McArdle's disease, daily doses of creatine at 60 mg per Kg (about 2.2 pounds) of body weight seemed to improve muscle function and lessen muscle fatigue. Higher doses seemed to worsen the condition, however. McArdle's disease involves the inability to produce energy from chemicals stored in muscle tissue. Muscle symptoms of individuals with muscular dystrophy and similar conditions have also seemed to be reduced by creatinine. Creatine supplements appeared to be effective in preserving sight for individuals with gyrate atrophy, a very rare condition affecting the muscles of the eyes. The use of creatine in all these conditions is under study and much more needs to be learned before creatine is proved to be effective for any of them.
Creatine may have non-muscular effects as well. In laboratory and animal studies, creatine and substances derived from it have shown inhibitory effects against cancer. One early theory is that creatine prompts cancer cells to disintegrate, but the exact ways it might work are not understood. In other laboratory, animal, and human studies, supplemental creatine may have had a lowering effect on cholesterol levels. It is thought that creatine may affect the way the body breaks down and uses cholesterol from foods, but this theory has not been confirmed by adequate research findings. Very early results from a few additional studies suggest that creatine may protect nerves from damage by chemicals and diseases. This effect may make it useful for treating conditions such as Parkinson's disease. All of these potential uses for creatine need further study before they can be recommended.
When should I be careful taking it?
Precautions
Some evidence suggests that creatine may worsen kidney conditions.
Creatine supplements are not recommended for individuals under 18 years of age because too little is known about possible long term effects. In addition, creatine may have different effects for children and teenagers than it does for adults.
Not enough is known about how creatine might affect a developing fetus or an infant to recommend its use during pregnancy or while breast-feeding.
What side effects should I watch for?
Major Side Effects
In continuous high doses (20,000 mg per day or more), creatine may contribute to high blood pressure -- possibly from water-retention. Water accumulation may also affect the function of the heart, kidneys, or liver.
Conversely, dehydration may also be possible during the use of supplemental creatine. Although creatine has not been proved to cause dehydration, it pulls water into muscle tissue, potentially leaving less water available for other body functions. Signs of dehydration range from dry mouth to fatigue. If it is severe, dehydration may cause the heart to beat rapidly. Athletes taking creatine are advised to drink additional fluids during and after exercise.
Less Severe Side Effects
Because creatine attracts and holds water in muscle cells, using it also includes gaining weight. Average amounts of weight gain seen during studies were between one pound and 4 pounds during the initial 5 days (of 20,000 mg per day). Long-term use of creatine may increase weight even more.
Other side effects associated with taking creatine include:
What interactions should I watch for?
Prescription Drugs
Theoretically, creatine may cause kidney damage because its by-product, creatinine, is filtered through the kidneys into urine. If it is taken at the same time as prescription drugs that might also damage kidney tissues, the risk of kidney damage may increase. Classes of prescription drugs that might cause kidney damage include:
Non-prescription strengths of non-steroidal anti-inflammatory drugs (NSAIDs) such as Advil, Aleve, ibuprofen, Motrin, naproxen, and many others have a slight risk of causing kidney damage. If creatine, which might also damage the kidneys, is taken at the same time as an NSAID, the risk of kidney damage could increase.
Herbal Products
Ephedra has been removed from the U.S. market. Its use is strongly discouraged. Individuals who take creatine and ephedra at the same time may have an increased risk of side effects. One case of a stroke has been reported in an individual who was taking several dietary supplements that included creatine and ephedra. The exact cause of the stroke is not known, but the combination of creatine and ephedra is best avoided.
Foods
Caffeine appears to cancel the exercise-enhancing effects of creatine when both are used together.
Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how creatine interacts with drugs, other herbals, and foods and the severity of those interactions, please use our Drug Interactions Checker to check for possible interactions.
Should I take it?
Up to 2,000 mg (2 grams) of creatine are produced each day by the kidneys and liver. Another 1,000 mg to 2,000 mg (one gram to 2 grams) per day comes from the diet -- primarily from meat and fish. Creatine concentrates mostly in the large (skeletal) muscles, where it is involved in producing energy and moderating muscle fatigue. An adult of average weight (about 155 pounds) stores about 120,000 mg (120 grams) of creatine and uses about 2,000 mg (2 grams) every day. However, intensive exercise uses up creatine. It is believed that muscle stores of creatine are decreased dramatically during the first few seconds of exercise. Then, creatine stores gradually replenish over several minutes. As the muscles use energy, creatine is changed into a waste product known as creatinine, which is filtered into the urine by the kidneys. Creatine supplementation may increase the amount of creatine reserve up to 140,000 to 150,000 mg (140 grams to 150 grams), but any excess creatine is lost in the urine.
Supplemental creatine is manufactured artificially by reacting certain chemicals. It is usually sold as citrate, monohydrate, or phosphate salts, which may be easier for the body to use. Although some individuals feel that one salt is more beneficial than the others, no study evidence proves that any one of them works better than the others. Supplemental creatine should be labeled as "100% pure" or "free of impurities", because undesirable byproducts may be produced during manufacturing. Currently, the International Olympic Committee allows Olympic athletes to use creatine while competing in events.
Dosage and Administration
Creatine is available in a number of oral dose forms, with the most reliably consistent being capsules and powders that are usually added to water, low-acid fruit juice (such as apple, grape, pineapple, or tomato juice), or a sports drink that contains carbohydrates. Some research suggests that taking creatine with carbohydrates improves the absorption of creatine. Fruit juices with high acid contents (grapefruit, orange, and other citrus fruit juices) may interfere with the body's absorption of supplemental creatine. One teaspoon of most creatine powders supplies about 5,000 mg (5 grams). Many containers of creatine come with a scoop or spoon that is marked in dosage levels.
Note: Taking commercially-packaged liquid forms of creatine is not recommended due to the likelihood that creatine breaks down in solution.
Dosing for creatine varies depending on the desired effect. One general recommendation for enhancing exercise capability is to take a high dose of creatinine -- 20,000 mg (20 grams or about 4 teaspoons) per day for the first 2 to 7 days and then to reduce the daily dose to 2,000 mg (2 grams). Similar results have been seen with a dose of 3,000 mg (3 grams) every day. Usually, daily amounts of creatine are divided into two doses that are taken 10 to 12 hours apart.
Summary
Creatine is sold mainly to athletes and bodybuilders who want to increase muscle and improve exercise ability. Because it may strengthen muscle, creatine may be useful for degenerative heart and muscle conditions such as muscular dystrophy. Its potential effects on muscle-related diseases and other conditions remain to be proved.
Risks
Creatine is not recommended for individuals with kidney conditions or for children under the age of 18 years old. Pregnant and breast-feeding women are advised to avoid taking it, as well.
Side Effects
Although a definite connection has not been proved, a few individuals have died or experienced kidney collapse while taking creatine. Dehydration is possible and water retention probably will result in weight gain. Less serious side effects may be muscle-related (such as cramps) or gastrointestinal (such as diarrhea or nausea).
Interactions
Theoretically, creatine supplementation may increase the risk of kidney damage is it is taken at the same time as drugs such as certain antibiotics, cyclosporine, or NSAIDs that also may damage kidney tissue. The combination of ephedra and creatine may have adverse effects. Caffeine may cancel or reduce creatine's exercise-enhancing effects.
Last Revised May 26, 2004
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Last Revised May 26, 2004
Eagle
Scientific Name: Creatine
Other Names: Creatine Citrate, Creatine Monohydrate, Creatine Phosphate
Who is this for?
Uses
After several prominent athletes acknowledged using it in the past few years, creatine is best known for possibly improving athletic performance. Although multiple studies have been conducted to assess the effect of creatine on exercise potential, results are mostly inconclusive. While muscles may become bigger when creatine is taken, the gain in size may be due mainly to more water being held in the cells of muscle tissue. Additionally, it is important to note that many of the studies were done in clinics or laboratory settings that do not necessarily duplicate conditions at actual athletic events. Most of the studies tested small groups of young, trained athletes who took many different doses and forms of creatine. In general, results of the studies show that creatine supplementation may offer younger individuals a benefit for improving repeated, intensive spurts of effort such as weight-lifting. Less apparent improvement or no effects occurred for more sustained exercise such as swimming laps. Based on the responses of some individuals, taking creatine may actually decrease the ability to maintain prolonged exercise. Results among older individuals were inconclusive with small benefits seen in some studies, but no exercise improvement in others.
Since the potential muscle-enhancing effect of creatine supplementation may affect all muscles in the body, it has also been studied for treating heart conditions and muscular disorders such as muscular dystrophy. Several small studies of individuals with heart failure have had mixed results. In some studies, creatine has appeared to have a direct effect on the heart, causing it to beat more forcefully. Other studies found no effect on the heart itself, although an increase in overall muscle strength was seen in many of the individuals receiving creatine supplements. Creatine may have been more beneficial for improving heart function when it was injected into a vein than when it was taken orally. For individuals with muscle-weakening conditions, results of studies are also inconsistent. Animal studies show that creatine may lessen the effects of Huntington's disease, a hereditary degenerative disorder of brain tissue. In studies of individuals with a rare genetic condition known as McArdle's disease, daily doses of creatine at 60 mg per Kg (about 2.2 pounds) of body weight seemed to improve muscle function and lessen muscle fatigue. Higher doses seemed to worsen the condition, however. McArdle's disease involves the inability to produce energy from chemicals stored in muscle tissue. Muscle symptoms of individuals with muscular dystrophy and similar conditions have also seemed to be reduced by creatinine. Creatine supplements appeared to be effective in preserving sight for individuals with gyrate atrophy, a very rare condition affecting the muscles of the eyes. The use of creatine in all these conditions is under study and much more needs to be learned before creatine is proved to be effective for any of them.
Creatine may have non-muscular effects as well. In laboratory and animal studies, creatine and substances derived from it have shown inhibitory effects against cancer. One early theory is that creatine prompts cancer cells to disintegrate, but the exact ways it might work are not understood. In other laboratory, animal, and human studies, supplemental creatine may have had a lowering effect on cholesterol levels. It is thought that creatine may affect the way the body breaks down and uses cholesterol from foods, but this theory has not been confirmed by adequate research findings. Very early results from a few additional studies suggest that creatine may protect nerves from damage by chemicals and diseases. This effect may make it useful for treating conditions such as Parkinson's disease. All of these potential uses for creatine need further study before they can be recommended.
When should I be careful taking it?
Precautions
Some evidence suggests that creatine may worsen kidney conditions.
Creatine supplements are not recommended for individuals under 18 years of age because too little is known about possible long term effects. In addition, creatine may have different effects for children and teenagers than it does for adults.
Not enough is known about how creatine might affect a developing fetus or an infant to recommend its use during pregnancy or while breast-feeding.
What side effects should I watch for?
Major Side Effects
In continuous high doses (20,000 mg per day or more), creatine may contribute to high blood pressure -- possibly from water-retention. Water accumulation may also affect the function of the heart, kidneys, or liver.
Conversely, dehydration may also be possible during the use of supplemental creatine. Although creatine has not been proved to cause dehydration, it pulls water into muscle tissue, potentially leaving less water available for other body functions. Signs of dehydration range from dry mouth to fatigue. If it is severe, dehydration may cause the heart to beat rapidly. Athletes taking creatine are advised to drink additional fluids during and after exercise.
Less Severe Side Effects
Because creatine attracts and holds water in muscle cells, using it also includes gaining weight. Average amounts of weight gain seen during studies were between one pound and 4 pounds during the initial 5 days (of 20,000 mg per day). Long-term use of creatine may increase weight even more.
Other side effects associated with taking creatine include:
- Diarrhea
- Dizziness
- Muscle cramps
- Nausea
- Stomach pain
What interactions should I watch for?
Prescription Drugs
Theoretically, creatine may cause kidney damage because its by-product, creatinine, is filtered through the kidneys into urine. If it is taken at the same time as prescription drugs that might also damage kidney tissues, the risk of kidney damage may increase. Classes of prescription drugs that might cause kidney damage include:
- Aminoglycoside antibiotics such as Amikacin, Nebcin, or tobramycin
- Immunosuppressants such as cyclosporine
- Non-steroidal anti-inflammatory drugs such as Advil, Aleve, ibuprofen, Motrin, or naproxen
Non-prescription strengths of non-steroidal anti-inflammatory drugs (NSAIDs) such as Advil, Aleve, ibuprofen, Motrin, naproxen, and many others have a slight risk of causing kidney damage. If creatine, which might also damage the kidneys, is taken at the same time as an NSAID, the risk of kidney damage could increase.
Herbal Products
Ephedra has been removed from the U.S. market. Its use is strongly discouraged. Individuals who take creatine and ephedra at the same time may have an increased risk of side effects. One case of a stroke has been reported in an individual who was taking several dietary supplements that included creatine and ephedra. The exact cause of the stroke is not known, but the combination of creatine and ephedra is best avoided.
Foods
Caffeine appears to cancel the exercise-enhancing effects of creatine when both are used together.
Some interactions between herbal products and medications can be more severe than others. The best way for you to avoid harmful interactions is to tell your doctor and/or pharmacist what medications you are currently taking, including any over-the-counter products, vitamins, and herbals. For specific information on how creatine interacts with drugs, other herbals, and foods and the severity of those interactions, please use our Drug Interactions Checker to check for possible interactions.
Should I take it?
Up to 2,000 mg (2 grams) of creatine are produced each day by the kidneys and liver. Another 1,000 mg to 2,000 mg (one gram to 2 grams) per day comes from the diet -- primarily from meat and fish. Creatine concentrates mostly in the large (skeletal) muscles, where it is involved in producing energy and moderating muscle fatigue. An adult of average weight (about 155 pounds) stores about 120,000 mg (120 grams) of creatine and uses about 2,000 mg (2 grams) every day. However, intensive exercise uses up creatine. It is believed that muscle stores of creatine are decreased dramatically during the first few seconds of exercise. Then, creatine stores gradually replenish over several minutes. As the muscles use energy, creatine is changed into a waste product known as creatinine, which is filtered into the urine by the kidneys. Creatine supplementation may increase the amount of creatine reserve up to 140,000 to 150,000 mg (140 grams to 150 grams), but any excess creatine is lost in the urine.
Supplemental creatine is manufactured artificially by reacting certain chemicals. It is usually sold as citrate, monohydrate, or phosphate salts, which may be easier for the body to use. Although some individuals feel that one salt is more beneficial than the others, no study evidence proves that any one of them works better than the others. Supplemental creatine should be labeled as "100% pure" or "free of impurities", because undesirable byproducts may be produced during manufacturing. Currently, the International Olympic Committee allows Olympic athletes to use creatine while competing in events.
Dosage and Administration
Creatine is available in a number of oral dose forms, with the most reliably consistent being capsules and powders that are usually added to water, low-acid fruit juice (such as apple, grape, pineapple, or tomato juice), or a sports drink that contains carbohydrates. Some research suggests that taking creatine with carbohydrates improves the absorption of creatine. Fruit juices with high acid contents (grapefruit, orange, and other citrus fruit juices) may interfere with the body's absorption of supplemental creatine. One teaspoon of most creatine powders supplies about 5,000 mg (5 grams). Many containers of creatine come with a scoop or spoon that is marked in dosage levels.
Note: Taking commercially-packaged liquid forms of creatine is not recommended due to the likelihood that creatine breaks down in solution.
Dosing for creatine varies depending on the desired effect. One general recommendation for enhancing exercise capability is to take a high dose of creatinine -- 20,000 mg (20 grams or about 4 teaspoons) per day for the first 2 to 7 days and then to reduce the daily dose to 2,000 mg (2 grams). Similar results have been seen with a dose of 3,000 mg (3 grams) every day. Usually, daily amounts of creatine are divided into two doses that are taken 10 to 12 hours apart.
Summary
Creatine is sold mainly to athletes and bodybuilders who want to increase muscle and improve exercise ability. Because it may strengthen muscle, creatine may be useful for degenerative heart and muscle conditions such as muscular dystrophy. Its potential effects on muscle-related diseases and other conditions remain to be proved.
Risks
Creatine is not recommended for individuals with kidney conditions or for children under the age of 18 years old. Pregnant and breast-feeding women are advised to avoid taking it, as well.
Side Effects
Although a definite connection has not been proved, a few individuals have died or experienced kidney collapse while taking creatine. Dehydration is possible and water retention probably will result in weight gain. Less serious side effects may be muscle-related (such as cramps) or gastrointestinal (such as diarrhea or nausea).
Interactions
Theoretically, creatine supplementation may increase the risk of kidney damage is it is taken at the same time as drugs such as certain antibiotics, cyclosporine, or NSAIDs that also may damage kidney tissue. The combination of ephedra and creatine may have adverse effects. Caffeine may cancel or reduce creatine's exercise-enhancing effects.
Last Revised May 26, 2004
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Last Revised May 26, 2004
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