Creatine self-study

Summary

I took creatine, a safe, cheap and particularly promising nootropic drug and measured its effect on my cognition, with fairly equivocal results.

Nootropics

Nootropics, or cognitive enhancing drugs, like caffeine and theanine have been used for centuries. The search for better nootropics is ongoing. Of the many potential nootropics that have been tested, few have been useful. Even promising substances like modafinil and creatine are supported as intelligence enhancers by only a few high quality trials and reviews of many of low quality ones. However, as Gwern describes, there also some problems with distinguishing intelligence-enhancing and stimulant effects.

Creatine

Creatine (examine.com is a particularly promising nootropic to investigate. It is safe safe, cheap (at about 5c/day), and shows promise as a cognitive enhancer in a few trials. It is in widespread use as a bodybuilding supplement and its main side-effects are mild gain of fluid in muscle tissue and mild nausea if not taken with water. We have some good reasons to think it might improve cognition: First, there is a good mechanism. In the brain, it improves energy availability, just as it does in muscle. This jibes with the fact that it normally crosses the blood brain barrier, and that if the proteins that would transport it across the blood brain barrier are faulty, then retardation syndromes are seen. In Gwern’s meta-analysis of three studies, it showed a gain of 11 IQ points (0.76 SD), and had a middling score in the r/nootropics survey. Furthermore, creatine is known to be in red meat, and its effects have been larger in vegetarians. As a vegetarian, this gives me an additional reason to expect that creatine might give me a big intelligence boost.

Experimental Procedure

My plan was to take 5g creatine for two weeks, and to measure my cognition in this period and for at least week before and after.

After I took creatine for 11 days, I wasn't noticing any major changes, so I increased the dose to 10g for 5 days. i.e. I took creatine for 16 days in total.

Metrics

I took three measures of my cognition at roughly noon each day:
1 – I subjectively rated my cognitive ability from 1 to 10.
2 – I completed a twenty-minute battery of tests from Cambridge Brain Sciences: spatial span, double trouble, object reasoning, rotations, hampshire tree task and spatial slider.
3 – I completed ten medical questions.

Results

The number of questions I answered correctly each day varied from 3-8 questions per day. My average score was 5.7 on creatine, the same as my average score off creatine. My subjective cognitive ability was 7.4 on creatine and 6.6 off creatine. This gave a t-statistic of 2.61, with a p-value of 0.016 on one-tailed t-test, suggesting that creatine had a positive effect on my subjective sense of cognitive ability. For objective measures of my cognitive ability, there was not a significant improvement. Taking my mean performance in all tests (standardised for each test), there was a t-statistic of 0.51, with a p value of 0.308, suggesting no significant improvement in cognition.

These are shown in Figure 1.

Figure 1: Subjective Cognitive Ability, Medical Questions and Creatine. These are plotted on a shared horizontal axis.

My performance of the cognitive battery improved significantly over the first ten days. By the time I took creatine, it was starting to stabilize, but continued to improve slowly throughout my time on creatine and afterwards.

Figure 2: Cognitive Battery. Performance in five cognitive tests performed daily is plotted alongside creatine dosage.

Discussion

Since the only improvements on my cognition were on the subjective measures, this could suggest that it arose from a placebo effect.

However, there are various difficulties with interpretation. There was a significant learning effect in test performance. The results were fairly short and duration, and also pretty noisy, which is tricky when creatine is hypothesised to have some lag time before it starts working.

Maybe I should keep taking creatine despite the modest negative result, I'm not sure. Ideally, some others would also measure their results. Ultimately, if we ran an RCT with about 50 participants, and Raven's Progressive Matrices before, during and after creatine consumption, we might have a much better idea.

Conclusion

Creatine has not greatly improved my intelligence. However, given that creatine is safe and cheap, it may be beneficial for many people - especially vegetarians - to take creatine anyway. We can get better answers with a big RCT.

Last updated May 2015