- Aug 14, 2018
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"What creatine does" is a question best answered with a little physiology, because the mechanism is genuinely simple and it explains almost everything else people argue about. Muscles run on ATP, and a muscle only holds a few seconds' worth of it. When ATP is spent it becomes ADP, and the muscle needs to rebuild it before it can keep contracting hard. Creatine, stored in muscle as phosphocreatine, donates a phosphate group back to ADP and turns it into ATP again. That is the whole trick: it is a rapid recycling system for the fuel of short, hard effort.
That mechanism explains why the benefits cluster where they do. A heavy set of five, a sprint, a jump — these are efforts where ATP turnover is the limiting factor, and extra phosphocreatine means a few more seconds of full power before fatigue forces the pace down. It also explains why creatine does very little for a slow jog: during long steady exercise the body leans on other energy systems, and the phosphocreatine pool is not the bottleneck.
It also explains the water-weight effect that confuses so many first-time users. Creatine pulls water into muscle cells along with it, which is part of how it works, not a side effect to be worried about in a healthy person. The scale goes up a kilogram or two, the muscles look slightly fuller, and none of it is fat. People who stop taking it lose that water again, which is why some conclude it "stopped working" — it never was a permanent change, it was a fuel store being kept full.
Understanding the mechanism also sets realistic expectations. Creatine does not build muscle by itself, it does not replace protein, and it does not rescue a program with no progression. What it does is let a trained person do slightly more high-quality work, session after session — and that accumulated work is where the gains come from.
Did knowing the mechanism change how you think about it, or is the research result enough on its own?
That mechanism explains why the benefits cluster where they do. A heavy set of five, a sprint, a jump — these are efforts where ATP turnover is the limiting factor, and extra phosphocreatine means a few more seconds of full power before fatigue forces the pace down. It also explains why creatine does very little for a slow jog: during long steady exercise the body leans on other energy systems, and the phosphocreatine pool is not the bottleneck.
It also explains the water-weight effect that confuses so many first-time users. Creatine pulls water into muscle cells along with it, which is part of how it works, not a side effect to be worried about in a healthy person. The scale goes up a kilogram or two, the muscles look slightly fuller, and none of it is fat. People who stop taking it lose that water again, which is why some conclude it "stopped working" — it never was a permanent change, it was a fuel store being kept full.
Understanding the mechanism also sets realistic expectations. Creatine does not build muscle by itself, it does not replace protein, and it does not rescue a program with no progression. What it does is let a trained person do slightly more high-quality work, session after session — and that accumulated work is where the gains come from.
Did knowing the mechanism change how you think about it, or is the research result enough on its own?