Creatine is produced in the muscles, but it is also absorbed through food, especially meat and fish. A positive effect on muscle growth and performance is possible, but not for everyone who does sports. As muscle builds up, there is also water retention and weight gain.
Creatine is a nitrogen compound mainly produced in the liver and kidneys from the amino acids glycine, arginine, and methionine, which the body produces itself. However, creatine is also absorbed through food: fish and meat contain approx. 0.5 g creatine per 100 g food. Milk also contains traces of creatine. While supplementing, most athletes use creatine monohydrate, which is the most common and best-studied form of creatine.
The total body of creatine in an athlete weighing 70 kg is approx. 120 g, of which approx. 95% is in the skeletal muscles. Approx. 2 g is broken down every day and excreted in the urine as creatinine. When taking creatine – even at low doses – increased creatine to creatinine ratio can be found in the urine. The loss is replaced by the body’s own synthesis and ingestion through food. The practically creatine-free diet of vegetarians does not lead to deficiency symptoms, but regular meat and fish consumers have about 10% higher creatine stores than vegetarians.
In conjunction with phosphate, creatine has various important functions for providing energy in muscles. Its best-known role is the provision of phosphate for the resynthesis of the energy supplier ATP (adenosine triphosphate) from ADP (adenosine diphosphate). In the fast muscle fibers (type II) there is a higher concentration of creatine than in slow muscle fibers (type I).
Basically, a distinction is made between two different charging protocols, whereby with Fast loading the maximum creatine values in the muscle are reached faster than with Slow loading. However, the maximum creatine value is identical for both applications. With the Fast Load, 0.3 g / kg or 1.4 g / lb of body weight are administered daily, divided into approx. 4-5 individual servings. The charging phase lasts for 5 days. In the subsequent maintenance phase, 3 to 5 grams of creatine are supplied per day.
The maintenance phase lasts 4 to 12 weeks. This should be followed by a break of several weeks (withdrawal phase, approx. 4 weeks or longer). With slow load, the same or only slightly more creatine is supplied in the loading phase as in the maintenance phase, but for a longer period of time (approx. 4 weeks). Then, as with the Fast Load, the maintenance phase and the withdrawal phase are added.
Creatine supplementation makes sense above all if you already have experience in strength training and are able to apply a corresponding supra-threshold stimulus to the muscles in strength training. Creatine can then support muscle building and lead to an increase in strength.
Fast Load Phase: 5 Days Long
Maintenance Phase: 4 to 12 Weeks Long
Withdrawal Phase: 4 to 8 Weeks Long
Slow Load Phase: 4 Weeks Long
Maintenance Phase: 4 to 12 Weeks Long
Withdrawal Phase: 4 Weeks to 8 Weeks Long
Creatine leads to a weight gain of 0.5 – 1.0 kg during the loading phase, as creatine osmotically “pulls” water into the cells and thus causes short-term water retention in the muscle cells. Depending on the individual reaction, further weight gain is possible in the long term (over months to years). Although individual cases of muscle spasms and strains, tendon problems, or gastrointestinal intolerance have been described when taking creatine, no scientific studies have yet been carried out to prove these side effects.
People with existing kidney problems or people with an increased risk of kidney diseases (e.g. diabetes, high blood pressure) are not advised to take creatine. In healthy people, based on current knowledge, it can be assumed that kidney function will not be impaired. Although creatine can have a performance-enhancing effect, this does not mean that the intake is beneficial for everyone who does sports, nor that no undesirable effects can occur. If you consume creatine for a long time, for example, the production of this substance in your body will decrease.
The consumption of food supplements with creatine is considered safe. Studies in which the test subjects took 30 grams/day for 5 years did not find any harmful side effects. The excess amount of creatine is then simply excreted in the urine. However, if very high amounts of creatine are taken all at once, nausea, vomiting or diarrhea can occur.
People with kidney disease should speak to their doctor or pharmacist before taking creatine. The reason: Excess creatine is usually excreted through the kidneys. At the moment it has not yet been finally clarified whether an increased creatine intake, in this case, has negative effects on health.