What Does Creatine Actually Do?

By Matthew Etzel

In recent years, a magical gym bro substance has made the rounds throughout the fitness industry. Thanks to the powers of marketing and bro-science, the actual purpose of creatine is often misunderstood. Let’s start with some fast facts:

  • Creatine is an amino acid (the building blocks of protein!)
  • An average healthy human stores 100-160 grams
  • Creatine is stored primarily in the skeletal muscles (95% muscles, 5% other organs)
  • The body synthesizes ~2g per day and takes in the rest through diet
  • One pound of red meat or fish contains roughly 2g of creatine
  • A typical creatine supplement is 5g daily in powdered form

As you might know, ATP is the energy currency of natural organisms, including humans. ATP is required for muscles to contract in every sport from ultramarathoning to swimming to golf. All of these sports rely on different systems for synthesizing ATP to keep the body moving.

The phosphagen system, specifically the ATP-PC (phosphocreatine) system, provides rapid energy replenishment during short bursts of intense activity by recycling ADP (an ATP byproduct) in the cytoplasm of muscle cells. This system involves the use of stored phosphocreatine to regenerate ATP directly, allowing for quick bursts of energy without the need for oxygen.

The phosphocreatine supply in muscles can sustain intense activities for roughly 10-15 seconds. The purpose of creatine supplementation is to increase phosphocreatine levels and extend the availability of energy for such activities. While the effect is relatively moderate and specific to the ATP-PC system (not benefitting low to medium efforts), evidence of performance improvements in specific high-intensity sports are widely documented and accepted by the scientific community. 

That’s basically it. As far as concrete and documented effects go, this is what we have. It’s worth mentioning that creatine doesn’t make you stronger, it lets you suffer for longer. As is the case with most sports supplements, at least the legal ones, it only works if you work. 

In the world of sports, creatine is pretty well understood. But science never stops. Newer research suggests that creatine may improve brain function and defend against degenerative brain diseases. Although the research is inconclusive for now, it’s always cool to see sports science bridge the gap between health and medicine.