Creatine may help cognition most when the brain is under strain

A 2018 systematic review - a study that gathers every trial on a question and weighs the results together - pooled randomised controlled trials, in which people are assigned by chance to take creatine or a dummy pill. It found that oral creatine may improve short-term memory and intelligence or reasoning in healthy people [1]. But the evidence was small: six studies and 281 participants. Results were mixed for:

• long-term memory
• attention
• executive function, the planning and self-control side of thinking
• reaction time
• word fluency, how quickly you can call up the right words
• response inhibition, the ability to stop yourself acting on an impulse
• mental fatigue [1]

The strongest negative result comes from healthy young adults. In a 6-week randomised trial, creatine made no clear difference to processing speed, episodic memory (memory for events you have lived through), or attention, and did not clearly change prefrontal cortex activation, which is activity in a brain region involved in planning and attention [2]. This fits the review finding that young people often show little or no change in thinking [1].

Older or metabolically stressed groups may be more relevant. In overweight women over 60, a higher creatine intake from food went with better performance on a task measuring selective attention and the ability to ignore distractions [3]. This was an observational study, one that watches people without changing what they do, so it cannot prove creatine caused the difference.

One double-blind placebo-controlled study - neither the participants nor the researchers knew who was taking the supplement and who was taking a dummy pill - tested creatine ethyl ester, a chemical variant of ordinary creatine sold on the claim that the body absorbs it more easily. It reported improvements on several measures of thinking, but the authors said the findings need repeating with better checks on whether people actually took their doses [4].

Animal and cell studies also suggest creatine can protect brain function under stress from inflammation, from ischaemia (a blood supply too poor to deliver the oxygen the tissue needs), or from toxins, but those findings do not directly prove benefits in healthy humans [8], [12], [15].

Creatine helps cells buffer and move energy. The brain has high and changing energy demands, and creatine is transported through the blood to tissues including the brain [9]. That is why researchers think it might matter more when brain energy supply is under pressure - such as ageing, stress, disease, inflammation, or low dietary intake [1], [3].

In cell and animal models, creatine and phosphocreatine - the stored form the body parks creatine in so it can release energy quickly - appear to protect neurons partly by supporting high-energy phosphate stores, molecules cells use to rapidly maintain energy availability [12].

In a rat model of mild cognitive impairment, creatine improved learning and recognition-memory deficits caused by LPS, a bacterial toxin researchers use to trigger inflammation in animal studies, and increased markers linked to synaptic plasticity, meaning the brain's ability to strengthen or remodel connections between neurons [15].

Other mechanistic work points toward mitochondria, the cell structures that produce usable energy. In a model of cerebral ischaemia - reduced blood flow to the brain, as happens in a stroke - creatine was linked to reduced mitochondrial damage and neuronal apoptosis, which is programmed cell death [8].

Reviews also connect creatine with brain energy metabolism, mitochondrial function, neuroprotection (shielding nerve cells from damage), and possibly hippocampal neurogenesis, the formation of new neurons in a memory-related brain region [7], [13].

The human evidence on thinking is still limited. The main systematic review included only six randomised trials and 281 people [1]. Some studies tested healthy young adults, who may already have enough brain creatine, or enough energy capacity, to see little benefit [1], [2].

Several included papers are not direct evidence that creatine supplementation improves thinking in healthy humans. Some are observational, some are reviews, and several use animal, cell, or disease models [3], [8], [12], [13], [15]. The results should not be stretched into a claim that creatine prevents dementia or broadly boosts brain performance.

The evidence also does not settle who benefits most. Vegetarians responded better than meat-eaters on memory tasks in the systematic review, but not across other areas of thinking [1]. Older adults, people under mental strain, and people with low dietary creatine are plausible groups to study, but the abstracts do not provide enough proof for firm guidance.

A practical way to read the evidence: a healthy 22-year-old looking for sharper focus should not expect much based on current trials, while an older adult, a vegetarian, or someone under high cognitive strain may be closer to the groups where creatine looks biologically plausible. The honest takeaway is to track outcomes that matter, such as memory-heavy work or attention under fatigue, rather than assume a broad brain boost.