Creatine is one of the most researched supplements in sport. It is also a substance your body produces itself and that occurs in ordinary food, which raises the question of what supplementation adds.
Where it comes from
Your body produces creatine itself from amino acids, in the liver, kidneys and pancreas. It is also present in food, particularly in meat and fish. An average diet including animal products supplies roughly one to two grams a day.
Around ninety-five percent of the creatine in your body is stored in your skeletal muscles, largely in the form of phosphocreatine.
What it does in your muscles
Creatine works in two ways.
As an energy system. Your muscles run on ATP, but the supply of it is minimal: under maximal effort it is gone within a few seconds. Phosphocreatine donates a phosphate group with which ATP is immediately replenished. That system is the fastest your body has, and it determines what you can do in the first seconds of a sprint, a heavy set or a jump.
The more phosphocreatine you have stored in your muscles, the longer you can sustain that replenishment. That is where the effect of supplementation lies: you raise the store above what you achieve through food alone.
Through the fluid balance in the muscle cell. Creatine is osmotically active and draws water into the muscle cell. As a result cell volume increases and muscles feel fuller. This also explains the one to two kilos of weight gain many people see in the first weeks: that is fluid in the muscle, not fat.
Why monohydrate
There are various forms on the market, often with claims about better absorption. Creatine monohydrate is by far the most researched form and the one on which the vast majority of the scientific literature is based. For newer variants the evidence that they offer added value is generally lacking.
Who it is relevant for
Creatine is most useful for effort that is short and intense, and that repeats. Strength training, sprinting, martial arts, team sports with frequent changes of pace. In prolonged low-intensity effort the system creatine acts on plays a much smaller role.
Vegetarians and vegans generally have lower baseline stores, simply because they miss the one to two grams from meat and fish.
About the author
Kemail Verhoeven is the founder of AP Nutrition. He has played sport for fifty years across basketball, martial arts, strength training and triathlon, and after a series of injuries and broken bones he immersed himself in injury prevention, recovery, nutrition and movement science. That knowledge is self-taught and forms the basis of the products AP Nutrition develops and manufactures in-house.
Related reading
Creatine side effects: what is true about the stories?
Creatine loading phase: is it needed?