The Creatine Alertness Edition

On caffeine, focus, and surprising research.

Ken Springer (KS) is a retired professor of education and author of the popular Substack newsletter Statisfied.

Ken here. It may now be a household name in the fitness community, but creatine wasn’t always the popular supplement it is today. In fact, the substance—found naturally in all of our muscle cells—only really hit the big time in 1998, after St. Louis Cardinals first baseman Mark “Big Mac” McGwire acknowledged using the widely available supplement during his record-setting seventy home run season.

Recently, creatine came back on my radar because of a new peer-reviewed study showing that it may offset the effects of sleep loss. Yes, creatine—the supplement that bodybuilders and other athletes use to build muscle and improve performance. I was startled. 

Most supplements aren't supported by credible research. The data is either weak or non-existent. (Insomniacs can try a "sleepy girl mocktail," but the only evidence it works is a bunch of recent TikTok videos.)

On the other hand, the new creatine study, conducted by researchers in Germany, is not only credible but exceptionally well-designed. The gist of it is that young adults spent the night in a lab where they were deprived of sleep, given creatine or a placebo, and then tested throughout the night. From midnight through 4 a.m., those who received creatine reported less fatigue, and performed significantly better on reaction time, memory, language, numeracy, and logical skills tests. (I describe the study in more detail here.)

Why is this interesting?

One study, even a well-designed one, isn’t enough to prove things one way or the other. However, there were some notably clever bits of methodology in this particular study that made it much more believable for me.

To start with, each participant actually came to the lab twice. On one occasion, they received creatine. On another occasion, at least 5 days earlier or later, they received the placebo. This is called a crossover design, and it's useful for filtering out the effects of individual differences. (In a small study, if one group takes creatine while a separate group takes a placebo, you might not be sure whether the benefits of creatine reflect pre-existing differences between groups. Maybe the creatine group includes healthier people, or people who are more used to sleep deprivation, or whatever.)

In addition, participants were comparable in age, health, and sleep quality, as well as in duration of sleep for two weeks prior to the experiment. To prevent bias, neither the participants nor the research assistants knew whether creatine or the placebo was being administered each time.

Finally, the cognitive and metabolic variables were wisely chosen. The cognitive variables included things like reaction time, working memory (e.g., the SPAN test), verbal skill (e.g., finding analogies), numerical fluency (e.g., completing number sequences), and logical reasoning.

These skills illustrate what psychologists call "fluid intelligence", or processing abilities that don't rely much on prior knowledge. (In contrast, "crystallized intelligence" refers to acquired knowledge and skills.)

Prior studies show that fluid intelligence is undermined by sleep deprivation. Ultimately, it's what we care about most when we're sleep-deprivedsleep deprived. I know how to turn my computer on, open Microsoft Word, and type grammatically correct sentences. This is all part of my crystallized intelligence, and it's not going to change anytime soon. But when I'm sleep-deprived, I type slowly, I make mistakes, I'm slower to organize my thoughts, etc. In short, my fluid intelligence suffers.

As for the metabolic variables, the researchers used non-invasive brain scanning techniques grounded in spectroscopy to address two questions:

• Did creatine get absorbed into participants' brain cells? In other words, does a single dose of creatine even have the potential to benefit neural processing?

• Did creatine cause changes in brain ATP, pH levels, and other signs that the neural effects of sleep deprivation had been reversed?

Measuring both cognitive and metabolic changes serves a corroborative purpose. Metabolic changes without cognitive ones wouldn't be useful, practically speaking. Cognitive changes without metabolic ones would be useful but mysterious. What Gordji-Nejad and colleagues found, roughly speaking, is that creatine supported cognition in a way that would be predicted due to its molecular impact on brain cells.