Creatine and cognition, and why diet decides the effect

1. 01

   The pooled read: six trials, 281 people, two domains

   A systematic review of randomised controlled trials in healthy individuals found six studies covering 281 people. There was evidence that short-term memory and intelligence or reasoning may improve, while long-term memory, spatial memory, memory scanning, attention, executive function, response inhibition, word fluency, reaction time and mental fatigue produced conflicting results (Avgerinos et al. 2018). Six trials is a small evidence base for a claim this widely repeated, and the review called for larger samples and for testing in people with cognitive impairment.

2. 02

   Young, well-fed adults: performance stayed unchanged

   The single most useful sentence in the review for setting expectations is that performance on cognitive tasks stayed unchanged in young individuals (Avgerinos et al. 2018). That is the group most likely to be buying creatine for cognitive reasons, and it is the group in which the pooled evidence found nothing. The suggested beneficiaries were aging and stressed individuals, which is a different population and a hypothesis rather than a demonstrated result. Buying creatine for the muscle evidence and treating any cognitive effect as a bonus is the defensible order of reasoning.

3. 03

   Vegetarians: the one subgroup with a replicated memory effect

   Creatine is found mostly in meat, fish and other animal products, and muscle creatine is known to be lower in vegetarians, so supplementation corrects a lower baseline. The review found vegetarians responded better than meat-eaters on memory tasks, with no group difference in other domains (Avgerinos et al. 2018). That pattern is what the underlying trials show directly: better memory in vegetarians rather than meat consumers in a 128-person study (Benton and Donohoe 2011), and a large working-memory and reasoning effect in an all-vegetarian sample (Rae et al. 2003).

4. 04

   The largest single effect: 5 g a day, six weeks, 45 vegetarians

   A double-blind, placebo-controlled crossover trial gave 45 young adult vegetarian subjects 5 g a day for six weeks. Creatine had a significant positive effect (p<0.0001) on both working memory, measured by backward digit span, and intelligence, measured by Raven's Advanced Progressive Matrices, and the authors noted both are tasks requiring speed of processing (Rae et al. 2003). The dose is the ordinary maintenance dose used for muscle, which means no separate brain protocol is needed to reproduce the exposure, only the six-week duration.

5. 05

   The variability finding, which applies to everyone

   In 128 young adult women given placebo or 20 g of creatine a day for five days, creatine did not influence verbal fluency or vigilance, and improved memory only in vegetarians. But irrespective of dietary style, it decreased the variability of responses on a choice reaction-time task (Benton and Donohoe 2011). Reduced variability without faster average responses is the signature of a more stable energy supply under load rather than a raised ceiling, which is consistent with creatine's role as a phosphate buffer rather than a stimulant.

6. 06

   The dosing catch: brain uptake may need more than muscle does

   A comprehensive review concluded that brain creatine is responsive to supplementation, but that higher or more prolonged dosing than the strategies typically used to raise muscle creatine may be required, and that the optimal strategy is unknown and an urgent research need (Dolan et al. 2019). This is the weak point in every brain-focused creatine claim: the trials showing cognitive effects used ordinary muscle doses, while the mechanistic literature suggests those doses may be at or below the threshold for meaningfully raising brain creatine.

7. 07

   When an effect is most likely: cognition under stress

   The same review found creatine most likely to exert an influence in situations where cognitive processes are stressed, naming sleep deprivation, experimental hypoxia, and more complex and therefore more cognitively demanding tasks, and noted that human data on mild traumatic brain injury remain limited (Dolan et al. 2019). That framing is consistent with the pooled finding of no effect in unstressed young adults. It also means the honest test of a personal effect is a demanding task under a real energy deficit, not a rested afternoon.

What people ask us next.

Q01

Does creatine improve cognition?

Conditionally. A systematic review of six randomised controlled trials in 281 healthy individuals found evidence that short-term memory and intelligence or reasoning may improve, with conflicting results across attention, executive function, reaction time, word fluency and other domains. Performance stayed unchanged in young individuals, and vegetarians responded better than meat-eaters on memory tasks (Avgerinos et al. 2018). The effect is not a general cognitive upgrade for everyone.

Q02

Does creatine help vegetarians more than meat eaters?

On memory tasks, yes. Creatine comes mostly from meat, fish and animal products, and muscle creatine is lower in vegetarians, so supplementation corrects a lower baseline. A 128-person double-blind study found creatine improved memory in vegetarians rather than in meat consumers, with no effect on verbal fluency or vigilance in either group (Benton and Donohoe 2011), and a crossover trial in 45 vegetarians found significant gains in working memory and Raven's matrices at 5 g a day for six weeks (Rae et al. 2003).

Q03

How much creatine should you take for brain benefits?

The trials used ordinary doses: 5 g a day for six weeks (Rae et al. 2003) and 20 g a day for five days (Benton and Donohoe 2011). No brain-specific protocol is established, and a comprehensive review concluded that higher or more prolonged dosing than that used for muscle may be required to raise brain creatine, with the optimal strategy currently unknown (Dolan et al. 2019). In practice that means the standard 3 to 5 g a day of monohydrate, assessed over weeks rather than days.

Q04

How long does creatine take to affect the brain?

The trial with the largest cognitive effect ran six weeks at 5 g a day (Rae et al. 2003), and the shortest ran five days at 20 g a day (Benton and Donohoe 2011). Since brain creatine may require more prolonged dosing than muscle to increase at all (Dolan et al. 2019), the longer window is the more reasonable assessment interval. Judging a cognitive effect after a few days at a maintenance dose is not a meaningful test.

Q05

Does creatine help with sleep deprivation?

It is the situation where an effect is considered most likely, though the human evidence is thin. A comprehensive review concluded creatine is most likely to influence cognition when cognitive processes are stressed, giving sleep deprivation, experimental hypoxia and more cognitively demanding tasks as the examples (Dolan et al. 2019). That is a mechanistic expectation supported by the pooled finding of no effect in rested young adults, not a demonstrated clinical result, and it is not a substitute for sleeping.

Q06

Is creatine worth taking if you eat meat and want cognitive benefits?

On the cognitive evidence alone, no. The pooled review found performance unchanged in young individuals and located the memory benefit in vegetarians rather than meat-eaters (Avgerinos et al. 2018). Someone eating meat and fish regularly already has higher baseline creatine stores, which removes the mechanism the vegetarian trials rely on. The muscle and strength evidence for creatine is far stronger and stands on its own; a cognitive effect should be treated as unproven in that population.