Creatine monohydrate is one of the most-studied supplements in the pharmacopeia. Not one of the most-studied sports supplements — one of the most-studied supplements, period. Thousands of human trials. A safety profile arguably better than ibuprofen.
And most people who take it have no idea what it does past making them a little bigger in the gym.
This piece is the rest of the story. Cognition under sleep deprivation. Older adults losing muscle. Women, where the myths run deepest. And why the fancy forms are wrong.
What creatine actually is
Creatine is a nitrogen-containing organic acid. Your body makes about half of what it uses (roughly 1 gram per day) from amino acid precursors in the liver, kidney, and pancreas. The rest comes from diet — primarily red meat, poultry, and fish. A pound of beef contains roughly 2 grams of creatine.
Once absorbed, creatine is stored in tissue as phosphocreatine. When cells need rapid energy — the first few seconds of maximal effort, or the sudden burst a neuron makes to fire a signal — phosphocreatine donates a phosphate to ADP to regenerate ATP. It is the fastest ATP resynthesis pathway your body has.
Skeletal muscle stores the majority. The brain stores less but uses it constantly. When you supplement creatine, both compartments load up over about three to four weeks.
The muscle data everyone knows
Fine, briefly. Creatine monohydrate at 3 to 5 grams per day increases lean body mass by 1 to 2 kg over 4 to 12 weeks in resistance-trained subjects. It increases strength on major lifts by roughly 5 to 15 percent. It reduces perceived exertion at fixed loads. All well-established. Kreider et al.'s ISSN position stand summarizes the evidence in comprehensive detail.
Some of that lean-mass gain in the first two weeks is intracellular water. That is not bloat — it is intramuscular hydration, which is a positive adaptation, not a cosmetic problem. It does not show up as puffiness on the skin.
The cognition data most people never hear
The brain uses ATP at extraordinary rates. Under normal well-rested conditions, phosphocreatine buffers handle the peaks. Under stress — sleep deprivation, high altitude, hypoxia, extended cognitive load — the buffer runs low. This is where creatine supplementation shows its cleanest neurological signal.
Sleep deprivation. The Gordji-Nejad et al. 2024 trial is the recent one worth reading. Single high-dose creatine (0.35 g per kg — roughly 25 grams for an average adult) given to sleep-deprived subjects produced measurable improvements in cognitive testing and detectable increases in brain phosphocreatine on MRS imaging within a few hours. This is not the standard maintenance protocol, and the effect required a big single dose. It demonstrated that creatine can improve cognitive performance under acute cognitive stress.
Vegetarian populations. Vegetarians and vegans start with lower muscle and brain creatine stores because they get none from diet. Rae et al. 2003 gave vegetarians 5 g per day for six weeks and measured a modest but statistically significant improvement on Raven's Progressive Matrices and working memory tasks. Omnivores in the same protocol showed smaller gains. Benton and Donohoe 2011 replicated the vegetarian-benefit pattern.
General memory and processing speed. McMorris et al. published a series of trials in the mid-2000s in sleep-restricted young adults showing 20 g per day for one week (a loading protocol) improved several cognitive endpoints — random movement generation, choice reaction time, spatial recall. Effect sizes were modest but consistent.
Older adults and cognitive function. A growing meta-analytic literature (Prokopidis et al. 2023, Xu et al. 2024) suggests short-term memory and reasoning tasks improve modestly in older adults on creatine. Not dementia therapy — modest cognitive support, in a population with lower endogenous creatine stores.
Depression. Small trials suggest creatine may accelerate response to SSRIs in some patients, particularly women. Lyoo et al. 2012 showed creatine added to escitalopram improved response versus SSRI alone in women with major depression. Effect signal, small sample. Not established therapy.
Older adults: sarcopenia is the big use case
Sarcopenia — the age-related loss of skeletal muscle — begins around age 30 and accelerates after 60. By 80, an average person has lost 30 to 40 percent of the muscle they carried at 30. This is why grandparents fall and cannot get up.
The Chilibeck meta-analyses (2017, updated 2021) pooled multiple trials of creatine plus resistance training in older adults. Combined therapy produced meaningfully larger gains in lean mass and strength than resistance training alone. Effect sizes in this population are among the largest in the creatine literature — because these subjects had the most room to move.
Dose is standard 3 to 5 grams per day. The intervention that must accompany it is resistance training. Creatine without a stimulus does very little. Creatine on top of two weekly strength sessions is one of the highest-leverage interventions available for someone over 60.
Women and creatine: the myths and the data
Three claims persist in the women's fitness space, all wrong.
Claim 1: creatine causes bloating and puffiness. No. Creatine draws water into muscle cells (intracellular), not into the subcutaneous space (extracellular). The scale may move up 1 to 2 pounds in the first two weeks — that is water inside your muscles, not water under your skin. It does not cause a puffy face or ankles.
Claim 2: creatine masculinizes. No. Creatine has no hormonal activity. It does not raise testosterone, does not aromatize, and does not alter menstrual cycles. Multiple RCTs in women show strength and lean-mass gains without changes to hormonal profiles or secondary sex characteristics.
Claim 3: women do not benefit as much as men. Complicated. Women start with lower endogenous creatine stores (about 70 to 80 percent of male levels). Some studies suggest women may respond less to loading protocols, though maintenance-dose response is comparable. The larger point: female creatine research has been under-resourced for decades. Recent reviews (Smith-Ryan et al. 2021) have argued that women may benefit more than men from chronic use during periods of hormonal transition — perimenopause and menopause, when muscle and cognitive function decline accelerate.
The practical statement: creatine is well-supported for women in resistance training, in aging, and in cognitive-support contexts. The myths do not survive contact with the literature.
Dose and loading: forget the loading phase
Standard maintenance dose is 3 to 5 grams per day, every day. That is the number the trial literature uses. Higher doses in the 10 to 20 gram range are used in specific research contexts (loading, acute cognition studies, some clinical populations) but offer no long-term advantage over 5 g maintenance.
The classic loading protocol — 20 grams per day for five to seven days, then 3 to 5 grams maintenance — was popular in the 1990s because it saturates muscle stores faster (about one week versus about four weeks). This is useful for athletes trying to peak by a specific date. For everyone else, skip loading. It causes more GI upset and no better long-term result.
Timing does not much matter. Morning, evening, pre-workout, post-workout — the meta-analytic effect of timing is small. Take it when you will remember to take it. Consistency beats timing.
Monohydrate versus HCl versus buffered versus "nano"
The supplement industry keeps trying to reinvent creatine because monohydrate is out of patent and sells for pennies per gram. None of the reinventions have beaten monohydrate on head-to-head trials.
- Creatine monohydrate. The form used in nearly every published RCT. Cheapest. Best-evidenced. What to buy.
- Creatine HCl. Marketed as more soluble and needing less water. True on solubility. Not clinically different at equivalent effective doses. Costs more.
- Buffered creatine (Kre-Alkalyn). Marketed as more stable at high pH. Head-to-head trials show equivalence to monohydrate. Costs more.
- Creatine ethyl ester. Marketed as better absorbed. Actually inferior to monohydrate on measured muscle creatine uptake. Skip.
- "Nano" or micronized creatine gummies. Marketing gimmicks built on the observation that smaller particles dissolve faster. Muscle uptake is not particle-size limited. Convenience form for people who dislike powder — pay the premium if that is you, but understand you are paying for convenience, not efficacy.
Creapure and purity: the one certification that matters
Creapure is the trademark for creatine monohydrate manufactured by AlzChem in Germany. It is not a nutritional advantage over cleanly-made monohydrate from other sources — it is a purity guarantee. Creapure batches are tested for creatinine, dicyandiamide, thiourea, dihydrotriazines, and heavy metals. The rest of the industry, particularly cheap Chinese-sourced monohydrate, has been documented to contain measurable contaminants.
Look for "Creapure" on the label. If not, look for a published third-party certificate of analysis. If neither, the brand is asking you to trust them without any independent evidence.
The kidney safety concern is unfounded
The one persistent worry about creatine is kidney safety, because creatine raises serum creatinine — a marker doctors use to estimate kidney function. But the elevated creatinine on creatine supplementation is not a sign of kidney damage. It is a downstream measurement effect. Muscle creatine is metabolized to creatinine at a fixed rate; more muscle creatine means slightly more creatinine in the blood, without any change in actual glomerular filtration.
Multi-year studies in healthy adults have shown no adverse renal effects at standard doses. A 2019 Antonio et al. review compiled long-term safety data across trials extending to five years and found no signal for kidney injury, liver injury, or cardiovascular harm.
Two caveats. If you already have chronic kidney disease, talk to your nephrologist before starting anything — including creatine. And if you take creatine and get a blood test, tell the doctor, so they do not misinterpret the elevated creatinine as a kidney signal.
Who should take creatine
The honest list is long.
- Anyone doing resistance training who wants better outcomes from the same work. This is the classical use case.
- Older adults doing strength training (or being convinced to start). The sarcopenia data is one of the most important applied uses of creatine.
- Vegetarians and vegans. Diet contributes zero creatine, so supplemental effects on both muscle and brain are larger than in omnivores.
- Adults with cognitively demanding jobs who periodically get short sleep. The cognitive support signal under sleep deprivation is one of the more interesting non-athletic uses.
- Women navigating perimenopause and menopause. The lean-mass, strength, and possibly cognitive benefits fit exactly the physiology that becomes vulnerable at that transition.
A 30-day creatine trial
Creatine is one of the few supplements where a 30-day trial is enough to see functional change if training is present.
- Buy monohydrate. Ideally Creapure-branded. Bulk powder is cheapest. A one-pound bag lasts three to six months at 5 g per day.
- Take 5 grams per day, every day. Mix into water, coffee, or a shake. Skip the loading phase.
- Also train. Two to three resistance sessions per week is the biological substrate for creatine to act on. Without training, creatine mostly just increases intramuscular water.
- Track one strength benchmark. Pick a compound lift or a pushup rep test. Measure it on day 1 and day 30.
- Compare. A 5 to 10 percent improvement in reps at the same weight, or 5 to 10 percent more weight at the same reps, is a real signal above what training alone would produce in a month.
The honest summary
Creatine monohydrate is boring, well-evidenced, and useful across a broader population than the fitness industry has publicized. It is not just for gym bros — it is for older adults trying to preserve muscle, vegetarians missing dietary intake, cognitively-demanding professionals dealing with periodic short sleep, and women whose research literature has been underrepresented for decades.
Buy monohydrate. Take 3 to 5 grams a day. Ignore the fancy forms and the gummies. Look for Creapure. Do not worry about the creatinine number on your labs — tell your doctor you take it. And pair it with actual training or actual cognitive demand. The supplement is a multiplier on what you were going to do anyway.