Creatine: how it works and why it is one of the most effective nutritional supplements for strength training

Kreatin: hur det fungerar och varför det är ett av de mest effektiva kosttillskotten för styrketräning
An article by Erik Hartman. Erik has recently completed his studies in medicine and technology at Lund University of Technology. He is chairman of Lund's Weightlifting Club, and active as a competitor both nationally and internationally via the university national team.

Creatine is one of the most common dietary supplements you come across in connection with training and is considered one of the most effective supplements you can take to increase your performance. It is also often referred to as one of the most researched and safe supplements – but how does it actually work?

The body's "energy currency" is a molecule called ATP (adenosine triphosphate) which is used for all possible mechanisms in our cells. Among them, it plays a key role in our movement, as it allows our muscles to contract and relax. The key property that ATP possesses is that it readily gives up a phosphate group, and is transformed from ATP to ADP in a reaction called de-phosphorylation. The recipient of the phosphate group, for example the motor protein myosin which is essential for muscle contractions (see Fig. 1), can use this to change its conformation resulting in muscle contractions.

Figure 1: Phosphorylation of myosin leads to a conformational change that in itself causes the motor domain to "pull" on the actin filament - leading to muscle contraction (Chang et al. JMCC, 2016).

Regenerating ATP is an energy-demanding process that takes place in the mitochondrion (the energy center of the cell) by metabolizing glucose, fat or amino acids. So this is the main reason why we eat. ATP is constantly regenerated, but during short intense energy-demanding moments, our ATP depot can run out. This is often the case with anaerobic (low-oxygen – not cardio) exercise, such as strength training, and is why we cannot do any number of repetitions of an exercise without resting. During rest, ATP is regenerated, and then we can do another set.

There is, however, a molecule that can regenerate ATP by phosphorylating ADP to ATP – i.e. the opposite reaction that causes ATP to be consumed. This is creatine phosphate (creatine). Creatine is created endogenously (by the body) by metabolizing amino acids, but we also get creatine in an omnivorous diet (because the animals we eat also create creatine). 95% of all creatine is stored in muscle cells, and is used in various reactions, including to act as a buffer during intense ATP consumption and regenerate the depots (Cooper et al. J Int Soc Sports Nutr, 2012).

Figure 2: Energy consumption over different time spans. Initially, the ATP stores are used, which are used up within a few seconds (imagine the time you can continuously perform an exercise). Next, creatine phosphate is used, which provides energy for another couple of seconds (from Biochemistry, by Stryer et al).

By taking creatine supplements, we increase the amount of creatine in the muscle cells, and thus we increase the amount of ATP that can be regenerated. This contributes to a performance increase as you can perform more repetitions before reaching your maximum capacity. There are several studies that examine the impact of creatine supplementation in various different sports and contexts. All show good effects on exercise capacity, hypertrophy (muscle growth) and recovery. Creatine has also been shown to contribute favorably to neurological processes and prevention
ra the development of neurodegenerative disorders and slows brain aging (however, this is not as proven as its effect on exercise performance) (Cooper et al. J Int Soc Sports Nutr, 2012).

If creatine is given in recommended doses and to people without a history of kidney problems, no negative effects have yet been demonstrated. However, you must be careful with dosage - especially if you have ailments that affect the kidney or if you take medicine that is
heavy burden on the kidney.

Taken together, we can state that creatine works - both in theory and in practice. We have both molecular-mechanistic evidence for its function, and we also see good results in scientific studies that demonstrate that it works as a performance-enhancing supplement. For further reading, the summary article by Cooper et al is recommended. "Creatine supplementation with specific view to exercise/sports performance: an update" from 2012.

HERE you will find 100% creatine monohydrate made in Sweden

Chang A. et al. "Role of myosin light chain phosphatase in cardiac physiology and pathophysiology", Journal of
molecular and cellular cardiology, 2016

Cooper R. et al. "Creatine supplementation with specific view to exercise/sports performance: an update" Journal of the International Society of Sports Nutrition, 2012

L. Stryer, (2019) Biochemistry. 9th Edition, WH Freeman and Company, New York.