The effects of creatine

Creatine is a nitrogen compound, produced mainly in the liver and kidneys from the amino acids glycine, arginine and methionine, which the body makes itself (synthesises). However, it is also taken in through food: fish and meat contain approx. 0.5 g per 100 g of food. Milk contains traces of creatine. The Swiss Federal Office of Public Health (BAG) approved creatine as a food supplement in 1995.

In most cases, creatine monohydrate is used for supplementation, which is the most widespread and best-researched form of creatine.

Metabolism, function, general effect

The total body store in a 70 kg athlete is approx. 120 g, of which approx. 95% is found in the skeletal muscles. Approx. 2 g are broken down daily and excreted in the urine as creatinine. While taking creatine – even at low doses – an increased ratio of creatine to creatinine can be detected in the urine. The loss is replaced by the body's own synthesis and by intake through food. A practically creatine-free diet in vegetarians does not lead to deficiency symptoms, although regular meat and fish eaters have approx. 10% higher creatine stores than vegetarians.

In combination with phosphate, creatine performs various important functions for energy supply in the muscle. Its best-known role is providing phosphate for the resynthesis of the energy supplier ATP (adenosine triphosphate) from ADP (adenosine diphosphate). Creatine is found in higher concentrations in the fast muscle fibres (type II) than in slow muscle fibres (type I).

Use and dosage

Basically, two different loading protocols are distinguished: with the Fast Load (fast loading) the maximum creatine levels in the muscle are reached more quickly than with the Slow Load (slow loading). However, the maximum creatine level is identical with both methods. With the Fast Load, 0.3 g / kg body weight (BW) is taken daily, divided into approx. 4-5 individual portions. The loading phase lasts 5 days. In the subsequent maintenance phase, 3 to 5 grams of creatine are taken per day. The maintenance phase lasts 4 to 12 weeks. This should then be followed by a break of several weeks (discontinuation phase, approx. 4 weeks or longer). With the Slow Load, the loading phase involves taking the same or only slightly more creatine than in the maintenance phase, but over a longer period (approx. 4 weeks). Afterwards, as with the Fast Load, the maintenance phase and the discontinuation phase are added.

Supplementation makes the most sense if you already have experience with strength training and are able to place a sufficiently overthreshold stimulus on the muscles during strength training. Creatine can then support muscle building and lead to an increase in strength.

Supplementation for young people is generally not recommended.

Possible side effects

During the loading phase it leads to a weight gain of 0.5 - 1.0 kg, as it osmotically draws water into the cells "pulling" it in, causing a short-term water retention in the muscle cells.

Depending on individual reaction, further weight gain over the long term (over months to years) is possible.

Although individual cases of muscle cramps and strains, tendon problems or gastrointestinal intolerances have been reported under creatine intake, there are so far no scientific studies that confirm these side effects.

People with existing kidney conditions or people with an increased risk of kidney disease (e.g. diabetes, high blood pressure) are advised against taking it. For healthy people, based on current knowledge, it can be assumed that kidney function is not impaired.