Creatine

Creatine is one of the best-studied and safest supplements available, and most adults get less of it from diet than their bodies could use. Best known for muscle and strength, it also supports brain energy under stress and cardiometabolic health — closer to a foundational nutrient for healthy aging than a sports supplement.

For decades creatine was filed under "sports nutrition" — a powder bodybuilders used to lift heavier. Modern evidence has reframed it as a conditionally essential nutrient with measurable benefits for muscle, brain bioenergetics, cognitive resilience under stress, and cardiometabolic health. The safety record is so extensive (over 685 trials in more than 12,800 participants, doses up to 30 g/day, durations up to 14 years) that it stands out even in a field with a high noise-to-signal ratio.

What creatine actually does

Cells run on adenosine triphosphate (ATP), and they burn through it fast — particularly muscle and brain tissue under load. Creatine works by buffering local energy supply through the phosphocreatine shuttle: it carries a high-energy phosphate group from the mitochondria (where ATP is generated) to the contractile machinery in muscle and the synaptic terminals in neurons (where ATP is consumed). Locally, that means a few extra seconds of full-power energy availability before the slower energy systems take over.^[1]

Recent work has expanded the picture. Beyond the energy buffer, sustained creatine availability appears to support mitochondrial proteostasis (quality control of mitochondrial proteins), reduce oxidative stress by sparing antioxidant cofactors like glutathione, and amplify the systemic release of muscle-derived signalling molecules (myokines) like brain-derived neurotrophic factor (BDNF) and insulin-like growth factor 1 (IGF-1) during exercise — the same molecules that support neurogenesis and synaptic plasticity in the brain.^[2]

The body makes about half of what it needs (roughly 1–2 g/day, synthesised in the liver and kidneys from arginine, glycine, and methionine). The other half comes from food — almost entirely red meat and fish. About 450 g (a pound) of beef or salmon delivers 1–2 g. 70% of adults over 65 consume less than 1 g of dietary creatine per day — well below requirement.^[3] Vegans and vegetarians get virtually none from diet.

What the evidence says

Strong — for muscle and strength when paired with resistance training; for cognitive resilience under metabolic stress (sleep loss, hypoxia, acute fatigue); for safety across all studied populations.

Moderate — for cognitive benefit in older adults and clinical populations; for glucose handling alongside exercise; for vegan/vegetarian cognitive baseline; for slowed bone loss and improved bone geometry in postmenopausal women with concurrent resistance training.

Weak / preliminary — for cognitive benefit in well-rested healthy young adults; for depression as an adjunct; for emerging fatigue indications (long COVID, fibromyalgia, myalgic encephalomyelitis/chronic fatigue syndrome, or ME/CFS); for pregnancy and perimenopause.

Caution — large randomised controlled trials (RCTs) in motor neurodegenerative disease (Parkinson's, Huntington's, amyotrophic lateral sclerosis) were null or stopped for futility despite a strong mechanistic rationale; creatine is not a disease-modifying therapy for these conditions.

Muscle and strength

The skeletal-muscle case is the most thoroughly validated. A 2025 systematic review and dose-response meta-analysis (61 trials) found that creatine combined with resistance training increased fat-free mass by ~1.4 kg and total body mass by ~0.9 kg over typical 8–12 week trial windows, without any meaningful gain in fat mass.^[4] A separate 2025 Nutrients meta-analysis (69 trials, ~1,900 participants) put numbers on the strength side: creatine plus training added ~5.6 kg to squat one-rep-max and ~1.4 kg to chest-press strength, while leg-press and handgrip gains were smaller and non-significant.^[5] One caveat worth keeping in view: that same analysis flagged significant publication bias for the chest-press result (Egger's test p = 0.0003), so the true average strength effect may be somewhat smaller than the literature suggests.

A useful 2025 methodological refinement: a University of New South Wales trial added a 7-day non-exercise "wash-in" period before starting training, then 12 weeks of resistance training.^[6] After the wash-in, the creatine group had gained ~0.5 kg of "lean mass" — but it was almost entirely intracellular water, not new contractile protein. After the 12-week training program, creatine and placebo groups had gained the same ~2 kg of lean mass. Translation: in beginners, much of creatine's apparent short-term effect on the scale is fluid retention; the strict hypertrophic advantage shows up later, once neurological "beginner gains" plateau and the hard work of breaking strength ceilings begins. That timing fits the dose-response meta-analysis above, in which experienced lifters gained more fat-free mass than novices (1.82 vs 1.23 kg) — a roughly 50% larger effect, though the between-group difference did not reach statistical significance.

The practical implication for resistance training: creatine reliably enables more total work — extra reps at the same load, faster bar velocity, lower perceived effort. A 2025 double-blind crossover trial showed short-term creatine loading enhanced strength, reduced fatigue, and accelerated recovery in resistance-trained athletes.^[7] That extra work, sustained over months and years, compounds into real hypertrophy.

See Resistance training for the broader programming context.

Brain and cognitive performance

The most interesting development in creatine science over the past five years: the brain story.

The brain runs on roughly 20% of resting metabolic energy despite being only ~2% of body mass. Phosphocreatine is critical to maintaining that energy supply, especially under demand. But the brain's barrier (the blood-brain barrier) is much more selective than muscle's blood supply, so cerebral creatine stores are harder to load. Standard 3–5 g/day muscle-maintenance doses raise brain creatine by only modest amounts; doses in the 10–20 g/day range, sustained for weeks, are needed to lift cerebral phosphocreatine measurably.

When does cognitive benefit show up?

The honest answer requires a statistical caveat. A 2023 critique in Nutrition Reviews showed that an influential creatine-and-memory meta-analysis had double-counted multiple cognitive subtests from the same participants as if they were independent — a "unit of analysis" error that inflates the apparent effect size.^[8] In well-rested, healthy young adults the effect is essentially absent: a dedicated dose-response trial found no cognitive benefit from either 10 or 20 g/day over six weeks in 30 young adults.^[9] The broader read is that the cognition evidence base is weaker than popular coverage implies — even the older-adult memory signal below rests partly on the meta-analysis that critique targeted. Keep cognition claims tightly bounded to older, stressed, or vegetarian populations.

What remains robust is more interesting: the cognitive benefit is concentrated in populations under metabolic stress, or with elevated baseline demand:

Older adults: a 2023 meta-analysis of memory trials found a small overall benefit (standardised mean difference ~0.29), larger in adults aged 66–76 but with wide uncertainty and high between-study variability — and it is the same analysis flagged above for statistical over-counting, so read it as suggestive rather than settled.^[10]
Vegans and vegetarians: lower baseline muscle and brain creatine stores; supplementation tends to produce more measurable cognitive lift than in omnivores.
Clinical populations: pilot work in early Alzheimer's and depression suggests improvements in working memory and executive function, plausibly driven by restoration of cellular energy supply.

Sleep deprivation: the strongest acute brain effect

The most striking recent finding is creatine's ability to defend brain bioenergetics under acute stress. A 2024 Scientific Reports trial (Forschungszentrum Jülich, Germany) tested a single high-dose bolus (0.35 g/kg of body weight — roughly 25–30 g for a typical adult) given to participants undergoing 21-hour sleep deprivation.^[11]

Using two forms of brain magnetic resonance spectroscopy, the researchers tracked cerebral pH, the phosphocreatine-to-inorganic-phosphate ratio, and total ATP in real time. Creatine completely prevented the sleep-deprivation-induced drop in cerebral pH, sustained the phosphocreatine ratio, and stabilised brain ATP. The cognitive consequences were equally striking: less deterioration on logical reasoning, faster reaction times, and significantly better psychomotor vigilance vs placebo. Onset was measurable at 3 hours post-dose; peak benefit at 4 hours; sustained through ~9 hours.

That makes acute high-dose creatine a serious tactical intervention for situations involving forced wakefulness — military operations, overnight medical shifts, long-haul flights, emergency response. It is almost certainly the best-evidenced acute neuroprotective intervention for sleep loss available without prescription.

For chronic sleep regulation, the underlying problem is night-time sleep itself, not creatine — see Sleep. Creatine is a rescue intervention, not a substitute.

Where creatine has failed: motor neurodegenerative disease

The bioenergetic rationale made creatine an obvious candidate for slowing neurodegeneration — and large, well-powered trials tested it directly and came up empty. The NET-PD LS-1 Parkinson's trial randomised 1,741 patients to creatine or placebo for up to five years and was stopped for futility, with no effect on clinical progression.^[12] The CREST-E Huntington's trial (553 patients, up to 40 g/day) was likewise halted for futility, with the decline trend if anything slightly favouring placebo.^[13] Multiple ALS RCTs were negative as well. The honest read: creatine has repeatedly failed in motor neurodegenerative disease despite strong mechanism. The genuine clinical wins are elsewhere — the inborn disorders that block the body's own creatine synthesis (AGAT and GAMT enzyme deficiencies) respond dramatically to oral creatine, whereas creatine transporter deficiency (from mutations that disable the transporter gene) does not, because the molecule can no longer be carried into the cell.

Creatine across the female lifespan

Most creatine research was done in men, and the female-specific picture has only recently been pulled together. Women synthesise less creatine (roughly 20% lower) and eat 30–40% less of it than men, which is the basis for the argument that they may be more responsive to supplementation.^[14] Endogenous synthesis, transport, and creatine-kinase expression also shift with estrogen across the menstrual cycle, pregnancy, and menopause.

The strongest case is the menopause transition and beyond, where creatine plus resistance training may support muscle, bone (see below), and possibly sleep, fatigue, and mood — moderate evidence for muscle/bone, preliminary for the rest. Pregnancy and perimenopause remain under-researched: human pregnancy work is still at the dose-finding/pharmacokinetic stage, with observational links between higher maternal creatine and birthweight but no completed efficacy RCTs. (Note: this review was funded by a creatine manufacturer and several authors are industry advisors; the methodology is sound but the framing leans favourable.)

Bone health

In a 12-month double-blind RCT, postmenopausal women on creatine (~0.1 g/kg/day) plus supervised resistance training three times a week lost less femoral-neck bone mineral density (BMD) than placebo (−1.2% vs −3.9%) and gained femoral-shaft subperiosteal width — a geometric predictor of bone bending strength.^[15]

The important nuance: the benefit is slowed loss plus improved bone geometry, not a BMD gain, and it depends on concurrent resistance training. A 2018 meta-analysis found creatine does not robustly raise bone mineral density at the spine, hip, or whole body^[16] — positive signals appeared only with relative (0.1 g/kg) dosing and higher training frequency. No trial has yet been powered on fracture outcomes, so the fracture-risk claim remains hypothetical pending the dedicated multi-year trial now underway.

Mood and depression

There is a real but oversold signal here. A landmark 8-week RCT in 52 women with major depression found that adding 5 g/day creatine to escitalopram roughly doubled remission (52% vs 26%) and produced a large extra drop in depression scores.^[17] But that is a single small, women-only trial. The most recent meta-analysis (11 trials, 1,093 participants) found the pooled effect was small — about 2.2 points on the 17-item Hamilton Depression Rating Scale (HAM-D), below the ~3-point threshold for clinical importance — with high heterogeneity, very low certainty under the GRADE evidence-grading framework, and evidence of publication bias favouring creatine; remission was more than three times as likely (odds ratio 3.6) but treatment response was no better than placebo.^[18] Treat creatine as a plausible, low-risk adjunct to standard antidepressant therapy — possibly needing higher doses (≥5–10 g/day) and longer trials to confirm — not a stand-alone treatment.

Emerging: fatigue and post-viral conditions

A newer line of work treats creatine as a bioenergetic support in chronic-fatigue states. Small RCTs report raised intramuscular phosphocreatine and improved muscle function in fibromyalgia, and reduced fatigue in post-COVID-19 fatigue syndrome.^[19] ME/CFS evidence is mostly feasibility/imaging work. Label all of this preliminary: samples are small and some trials carry industry framing. Note a dose tension — chronic-disease reviews propose 10–30 g/day, yet the clearest long-COVID signal came from the lower 4–6 g/day range.

Cardiometabolic health: resolving the diabetes paradox

For years, epidemiology data threw up a confusing signal: people with higher serum creatine levels had higher rates of type 2 diabetes. That association made some clinicians worry creatine supplementation might worsen glucose control.

A 2024 Science Translational Medicine paper from Anna Krook's group at the Karolinska Institutet decisively resolved the paradox.^[20] People with type 2 diabetes have down-regulated creatine kinase in skeletal muscle — meaning their muscle cells can't actually use the creatine they have. Unmetabolised creatine backs up into the bloodstream. The elevated serum creatine in diabetic patients is a consequence of impaired muscle bioenergetics, not a cause of diabetes.

In the other direction, in people with intact muscle metabolism, creatine combined with regular exercise reliably improves glucose handling — it upregulates GLUT4 (glucose transporter type 4) in muscle — the main route for insulin-independent glucose uptake, raises muscle glycogen capacity, and lowers fasting glucose and HbA1c (a marker of average blood sugar) when paired with multimodal exercise.^[21]

Translation: there's no signal that creatine causes or worsens type 2 diabetes. In active people, it modestly helps with the metabolic levers that matter. See Metabolic flexibility for the broader picture on glucose handling.

Form, dose, and timing

Form: stick with monohydrate

Multiple alternative forms exist — hydrochloride (HCl), nitrate, magnesium chelate, ethyl ester, buffered ("Kre-Alkalyn"), and others. They tend to dissolve better in water and feel less gritty, and the marketing emphasises "better absorption". The actual evidence:

Monohydrate is backed by 1,000+ trials over 50 years; bioavailability is essentially 100%.
The alternative forms have a handful of head-to-head trials, all of which show the same biological effect at equivalent doses — they don't beat monohydrate, they just match it.
Alternatives cost 2–5× more per gram.

There is no evidence-based reason to pay the premium. The International Society of Sports Nutrition position stand recommends monohydrate as the gold standard.^[22] Look for Creapure brand (German manufacturer, very high purity) or third-party tested generics.

Dose, by purpose

Goal	Dose	Notes
Muscle saturation, daily maintenance	3–5 g/day	Reaches full muscle saturation in ~28 days. No loading needed.
Optional fast-loading	20–25 g/day for 5–7 days, then 3–5 g/day	Saturates in ~1 week. May cause GI discomfort. Skip unless you have a specific deadline.
Brain saturation	10 g/day, sustained	Cerebral phosphocreatine rises measurably over weeks. Standard 3–5 g doses are insufficient for brain effects.
Acute cognitive rescue (sleep deprivation, hypoxia)	0.35 g/kg single dose (~25–30 g for typical adult)	Onset ~3 h; peak ~4 h; sustained ~9 h. Tactical use only.

Timing

The body's creatine stores are saturated rather than acutely sensitive — timing of the daily dose doesn't appear to matter much. Take it whenever is convenient. Take it with food, carbohydrate, or protein if you want a marginal absorption boost (insulin nudges muscle uptake). There is a mild lean toward post-exercise dosing in some trials, but follow-ups in older adults and athletes found timing immaterial; consistent daily intake matters far more than time-of-day. Caffeine does not meaningfully blunt creatine — the old concern rests on one unreplicated 1996 study, and co-ingestion (as in most pre-workouts) is fine.

Why some people respond less

Response varies between individuals. People with high baseline muscle creatine — habitual red-meat eaters, and those with type-II-fibre-dominant muscle — gain the least; vegetarians and low-baseline individuals gain the most. Part of this is genetic: the creatine transporter gene SLC6A8 governs cellular uptake, and common low-impact variants appear to create a continuum of transport efficiency that helps explain non-response.

Quality

Look for USP Verified, NSF Certified for Sport, Informed Sport, or Creapure branding. The supplement industry's quality variance is real; for most people, paying a small premium for a verified product is worth it.

Safety

This is where creatine's track record stands out even among well-tolerated supplements.

A 2025 systematic safety review across 685 trials and 12,839 participants covered every demographic imaginable — infants, pregnant women, the elderly, athletes, military personnel, clinical populations — at doses up to 30 g/day for durations up to 14 years.^[23] There were no clinically significant differences in serious adverse events vs placebo. Mild gastrointestinal discomfort and occasional muscle cramping were slightly more common with creatine but at very low absolute rates. An audit of 28.4 million adverse event reports over 50 years implicated creatine in 0.00072% — and most of those reports were confounded by multi-ingredient pre-workout blends, not pure monohydrate.

The kidney myth

The most persistent misconception: creatine damages kidneys. The mechanism people imagine: serum creatinine (a routine kidney lab) goes up after creatine supplementation. That's true — but it's because creatine metabolises non-enzymatically into creatinine, which is then filtered out by the kidneys. The bump is benign metabolic turnover, not damage.

The actual functional measure of kidney health — glomerular filtration rate (GFR) — is unaffected by creatine supplementation in healthy people. If you're getting blood work, mention you're taking creatine so the result isn't misread. The ISSN position stand and 2025 meta-analyses agree: no evidence of kidney damage in healthy populations from short- or long-term creatine use.^[24]

People with pre-existing advanced kidney disease should consult their nephrologist before supplementing — not because creatine is dangerous to them specifically, but because it complicates the standard kidney monitoring labs.

What about the GI side effects?

About 5% of supplementers report mild GI discomfort, mostly during loading phases or with very high single doses. Splitting the dose across the day, taking it with food, or skipping the loading phase usually resolves it. Cramping is rare and not consistently linked to creatine in controlled trials.

The hair-loss myth

The fear traces to a single 2009 study showing a transient rise in dihydrotestosterone (DHT) after creatine loading in rugby players — but DHT stayed within normal range and hair was never actually measured. A dedicated 12-week RCT has now tested the claim directly: 5 g/day in resistance-trained men, with dermatologist-assessed hair plus androgen panels. There was no effect on DHT, the DHT:testosterone ratio, or any hair parameter.^[25] The trial was men-only and 12 weeks, but it is strong evidence against the hair-loss claim.

Dehydration, cramping, cycling, and kidney stones

Dehydration and cramping. A systematic review of high-quality studies found no evidence that creatine impairs heat dissipation or fluid balance, and a dehydration trial found no extra cramping or thermoregulatory problems.^[26] Because creatine raises intracellular water, it may if anything aid thermoregulation.
No need to cycle. There is no physiological basis for "cycling" creatine. Stores stay saturated on 3–5 g/day, and years of continuous use show no transporter down-regulation requiring a washout.
Kidney stones. Creatine is not an oxalate, calcium, or uric-acid precursor, and there is no direct evidence it causes stones. Concentrated urine is the actual risk factor — so the practical advice is simply to stay well hydrated.

The conditionally essential argument

The strongest contemporary case for thinking of creatine as a near-essential nutrient (rather than an optional ergogenic aid) rests on three converging facts:

Endogenous synthesis declines with age. The liver and kidneys' creatine output decreases over the lifespan.
Dietary intake collapses in older adults. ~70% of people over 65 don't reach 1 g/day from food (and roughly 1 in 5 consume none). The U.S. average across all ages is only ~0.70 g/day. Even raw, meat is a modest source (beef/fish ~4.5–10 g/kg, chicken ~3.5 g/kg, plants ~0), and cooking destroys roughly 15–50% of it — so matching a 3–5 g dose would take on the order of ~1 kg of meat or fish a day, which is impractical and expensive. Red-meat consumption also tends to decline with age (digestion, finances, dental issues, behaviour).
The energy gap widens at the same time as cognitive and muscular reserves shrink. Sarcopenia, falls, frailty, and cognitive decline all share a bioenergetic component.

Beyond raw mass and strength, the functional payoff in older adults is concrete: creatine plus resistance training improves sit-to-stand and chair-rise performance in meta-analyses (though the evidence is low-quality and falls/fracture reduction is hypothesised, not demonstrated). The critical caveat: creatine alone, without resistance training, does little for muscle or function in older adults — the effect is conditional on training.

Sustained 3–5 g/day supplementation, paired with resistance training, appears to be one of the cheapest, lowest-risk, highest-ROI interventions available for older adults. It addresses muscle wasting and cognitive resilience simultaneously through the muscle-brain axis (myokines and shared bioenergetic mechanisms). At ~$0.05/g, that's a few dollars a month for a meaningful longevity-relevant input.

For vegetarians and vegans, the same argument applies more sharply, since dietary baseline is essentially zero. Supplementation here is closer to repletion than enhancement.

What to actually do

For most healthy adults: 3–5 g/day creatine monohydrate, taken whenever convenient, daily. No loading phase needed. Skip the alternative forms.

For older adults (65+) and people doing resistance training: Same protocol; the benefit-to-cost ratio is even more favourable.

For vegetarians or vegans: Same protocol; you're starting from a lower baseline, so the first weeks of supplementation may feel more noticeable.

For people targeting cognitive benefit: Consider 10 g/day sustained for ≥4 weeks. Brain saturation takes longer than muscle saturation.

For people facing acute sleep loss (shift work, long flights, emergency response): A 0.35 g/kg bolus (~25–30 g) before the demanding period; effect kicks in around 3–4 hours and lasts ~9 hours. This is a tactical use, not a daily one.

Before a routine kidney lab: Tell your clinician you take creatine so an elevated serum creatinine reading isn't misinterpreted.

What's overrated and what to know

Overrated:

Alternative forms (HCl, nitrate, ethyl ester, "buffered"). They match monohydrate, not beat it, at 2–5× the cost.
The loading phase. It just gets you to the same steady-state ~3 weeks faster, with more GI risk.
Marketing claims about "rapid hypertrophy" in beginners. Most of the early scale change is intracellular water, not new muscle.

Worth knowing:

Brain effects are dose-sensitive. A 3 g/day muscle dose probably won't move the needle on cognition; 10 g/day for several weeks is the threshold most cognitive trials clear.
Cognitive benefit shows up most clearly under stress. Sleep deprivation, hypoxia, mental fatigue, neurodegeneration, vegan/vegetarian diet — these are the conditions where the effect is reliably measurable. Well-rested young omnivores generally don't notice much.
Pair with training. Creatine without resistance training still has metabolic and cognitive benefits, but the muscle benefits — the strongest part of the evidence — only appear with structured loading.