What the research actually says.

Memory, attention, processing speed.

A 2024 systematic review and meta-analysis in Nutrition Reviews (Xu et al., 2024) pooled 16 randomised trials and reported small but consistent improvements in memory, attention time, and information-processing speed across healthy adults. Effects were larger in older adults and people under cognitive stress.

Vegetarians get the biggest jump.

People with low baseline brain creatine vegetarians and vegans tend to gain the most. In Rae et al. (2003), six weeks of 5g/day creatine improved working memory and Raven's progressive matrices scores in vegetarian adults versus placebo.

Cognitively demanding tasks.

An early controlled trial by Watanabe et al. (2002) using 8g/day for five days found improved performance on a serial-calculation task and reduced mental fatigue during the test. Doses were higher than ours; the mechanism supporting brain ATP regeneration under load is the same.

Mental Stack delivers 5g/day of Creapure®. The studies above used 5–8g/day, well within the everyday supplementation range.

Meta-analysis: 11 trials, 1,093 participants.

A 2025 systematic review and meta-analysis in the British Journal of Nutrition (Juneja et al., 2025) pooled 11 trials of creatine supplementation for depressive symptoms. The pooled effect favoured creatine over control, with the strongest signal when creatine was used alongside standard antidepressant treatment, not as a replacement.

Adolescent females with treatment-resistant depression.

In Kondo et al. (2011), adding 4g/day creatine monohydrate to SSRI therapy in adolescent females with SSRI-resistant major depression produced clinically meaningful reductions in depression scores after eight weeks versus placebo.

Adult females + escitalopram.

An eight-week RCT by Lyoo et al. (2012) added 5g/day creatine to escitalopram in women with major depressive disorder and reported faster, larger improvement than escitalopram alone. The effect was specific to women, consistent with sex differences in brain energetics.

Mechanism review.

A 2025 review in PMC (Smith-Ryan et al., 2025) summarises the brain-energetics rationale: depression and anxiety are associated with disturbances in cerebral phosphocreatine and ATP turnover, and creatine supplementation appears to partially correct these.

Honest framing. Creatine is not an antidepressant. The evidence supports it as a low-cost adjunct, something that may help when added to proper care. If you are struggling, please talk to a clinician.

Seven days of 5g, four times daily.

McMorris et al. (2006) tested young adults during 24 hours of sleep deprivation. Creatine supplementation preserved random number generation, balance, and mood relative to placebo, three things that fall apart fast when you're tired.

A single high dose, one night without sleep.

In Gordji-Nejad et al. (2024, Scientific Reports), a single oral dose of creatine (~0.35 g/kg, taken in the evening) measurably improved cognitive performance and increased brain phosphocreatine during a night of sleep deprivation, with effects detectable for hours.

For everyday wear-and-tear bad nights, long flights, broken sleep consistent 5g daily dosing is the supported pattern. The single-dose study is striking, but the dose is far above ours and not a routine recommendation.

Paediatric TBI, six-month creatine.

In Sakellaris et al. (2006), 39 children and adolescents with traumatic brain injury were randomised to oral creatine (0.4g/kg/day) or standard care for six months. The creatine group showed faster improvement in headache, dizziness, fatigue, and post-traumatic amnesia. A 2008 follow-up reported sustained advantages in cognition and behaviour.

These are clinical trials in children with diagnosed brain injury. They are not a license to dose around a concussion. They are why researchers think brain creatine matters.

Alzheimer's pilot trial: 20g/day for eight weeks.

Taylor et al. (2025, University of Kansas) ran an open-label pilot in 20 patients with Alzheimer's disease. Eight weeks of 20g/day creatine monohydrate raised brain creatine by ~11% (measured by magnetic resonance spectroscopy) and improved several cognitive measures. The trial is small, has no placebo arm, and is a pilot, not proof. It earns a citation, not a headline.

Mental Stack is a 5g/day capsule. We do not market our product as a treatment for Alzheimer's or any disease.

The position stand.

The International Society of Sports Nutrition position stand (Kreider et al., 2017; updated 2021) concludes that creatine monohydrate is the most effective ergogenic nutritional supplement currently available for athletes. Expected gains: ~5–15% improvement in maximal strength, sprint, and high-intensity work over weeks of daily 3–5g intake.

Recovery and lean tissue.

Reviews collected in the Nutrients special issue on creatine (2022) show consistent gains in lean mass, recovery between sets, and time-to-fatigue when creatine is paired with resistance training.

Bone & older adults.

An analysis of creatine + resistance training in postmenopausal women (Candow et al., 2022) reported small protective effects on lean mass and indicators of bone metabolism. The story for bone is suggestive, not closed.

Kidneys, hydration, hair.

Reviews of long-term creatine use in healthy adults, including the ISSN 2017 position stand and follow-ups, find no consistent evidence that creatine harms kidney function, causes dehydration, or accelerates hair loss. The hair-loss story comes from a single 2009 rugby study showing a DHT change; it has not been replicated and there is no measured hair-loss endpoint anywhere in the literature. We're not telling you it's impossible, we're telling you the evidence is thin.

Water weight is real, and small.

Creatine pulls a small amount of water into muscle cells. Most people see ~0.5–1 kg of intracellular water in the first weeks. It is not bloat.

What creatine is not.

It is not a stimulant. It is not a nootropic in the caffeine sense. It will not replace sleep, training, therapy, or medication. It is a slow, steady substrate, a bigger fuel tank, not a faster engine.

If you have kidney disease, are pregnant, or take prescription medication, talk to your doctor before starting any supplement, including ours.