Place · Level 3 · Supplement
Creatine monohydrate
被研究最透 · 证据 A 级 · 也是少有的安全冷门 — 营养补剂界的太干净到不像补剂
Story path
Chapter 1
What is it
What is it
Creatine (methylguanidinoacetic acid) is a small derivative of three amino acids — arginine, glycine, and methionine — synthesized in the liver, kidney, and pancreas.
It isn't an essential nutrient (you'd live fine without it), but endogenous synthesis only covers basal turnover (~1 g/day); the rest comes from red meat and fish (1–2 g/day).
Total body pool is ~120–140 g, 95% in skeletal muscle — about 2/3 stored as phosphocreatine (PCr) and 1/3 as free creatine.
It isn't an essential nutrient (you'd live fine without it), but endogenous synthesis only covers basal turnover (~1 g/day); the rest comes from red meat and fish (1–2 g/day).
Total body pool is ~120–140 g, 95% in skeletal muscle — about 2/3 stored as phosphocreatine (PCr) and 1/3 as free creatine.
Why supplementation works
The key asymmetry: a normal diet (1–2 g/day) only fills muscle stores to 60–80% saturation, leaving 20–40% headroom.That headroom is the physical reason supplementation works — not 'fixing a deficiency' but topping up because the tank can hold more.
A few common scenarios:
5 g/day × 4 weeks raises muscle PCr by ~20–30%, near the saturation ceilingStrict vegetarians start ~10–15% lower at baseline, so the gain is more obviousBeyond 5 g/day the excess is urinated out — it does not accumulate indefinitely
This 'saturation model' dictates every aspect of creatine use — you're filling a tank, not taking a daily nutrient. Once full, 3–5 g/day maintains it.
Chapter 2
Mechanism · ATP buffer
Mechanism · ATP buffer
adenosine triphosphate: The cell's universal energy currency — almost everything that costs energy spends it. is the cell's direct energy currency, but muscle stores only enough ATP for ~2 seconds of maximal output.
PCr (phosphocreatine) is ATP's fast backup — its phosphate bond carries slightly more energy than ATP's:
PCr + ADP → ATP + Cr (catalyzed by creatine kinase / CK, millisecond-fast)
PCr stores cover 8–12 seconds of maximal output — the 'phosphocreatine system', the first of three energy systems alongside glycolysis (~30 s to 2 min) and oxidative (sustained).
PCr (phosphocreatine) is ATP's fast backup — its phosphate bond carries slightly more energy than ATP's:
PCr + ADP → ATP + Cr (catalyzed by creatine kinase / CK, millisecond-fast)
PCr stores cover 8–12 seconds of maximal output — the 'phosphocreatine system', the first of three energy systems alongside glycolysis (~30 s to 2 min) and oxidative (sustained).
Downstream gains
After muscle PCr rises ~20%, several things improve at once:1. High-intensity output lasts longer: short bursts (lifting, sprinting, jumping) hold pace through seconds 6–12; rep capacity rises ~14% (Branch 2003 meta)
2. Faster between-set recovery: PCr is replenished oxidatively during rest — bigger stores refill faster, so the next set holds form
3. Indirect hypertrophy: creatine itself doesn't synthesize protein, but the extra 1–2 reps or extra weight accumulate into a hypertrophic stimulus over 8–12 weeks
4. Cellular water influx: creatine pulls water into muscle cells, total body water rises 1–2 kg; cells swell — part is cell-water hypertrophy, but studies confirm real fiber cross-section also grows
5. Anti-oxidant and anti-inflammatory side-effects: weak signal but repeatedly observed, correlating with modest reductions in post-training inflammation markers
6. Brain PCr stores also rise: this is the molecular starting point for the cognitive evidence later (the brain also uses PCr to buffer adenosine triphosphate: The cell's universal energy currency — almost everything that costs energy spends it.)
Chapter 3
Evidence tiers
Evidence tiers
Creatine is one of the few supplements where nearly every application has been validated by independent RCTs. But evidence strength varies sharply across applications — this is where our 'strict evidence' stance demands precision.
A-tier (multiple metas + ISSN position): high-intensity short-burst performance, strength-training hypertrophy, inter-set recoveryB-tier (single meta or several RCTs): sarcopenia + resistance training synergy, mild concussion recovery, postpartum fatigueC-tier (small RCTs or mechanism): long-duration cognitive tasks, depression adjunct, muscular dystrophy, ALSEssentially no evidence: fat loss, anti-wrinkle, longevity
A-tier (multiple metas + ISSN position): high-intensity short-burst performance, strength-training hypertrophy, inter-set recoveryB-tier (single meta or several RCTs): sarcopenia + resistance training synergy, mild concussion recovery, postpartum fatigueC-tier (small RCTs or mechanism): long-duration cognitive tasks, depression adjunct, muscular dystrophy, ALSEssentially no evidence: fat loss, anti-wrinkle, longevity
ISSN position
The International Society of Sports Nutrition (ISSN) 2017 position stand (Kreider et al., JISSN) is the most authoritative current creatine review, covering 700+ studies.The five core ISSN conclusions (paraphrased):
> 1. Creatine monohydrate is the most effective legal sports-nutrition supplement currently available for increasing high-intensity exercise capacity and lean body mass
> 2. Available evidence does not support any negative health effect from creatine, including (a) standard doses in healthy adults, (b) short-term high doses, or (c) long-term use up to 30 years
> 3. With appropriate precautions and supervision, creatine can serve as a 'nutritional aid' for youth athletes to reduce injury and boost performance
> 4. There is no scientific basis for banning creatine use by professional sports teams / leagues
> 5. Creatine monohydrate remains the most-studied, most clinically effective form — cheaper, more effective, and safer than all other forms (HCl, ethyl ester, kre-alkalyn, buffered, etc.)
This level of endorsement from a major society is rare in the supplement world. Note: the ISSN position doesn't open the door to broad 'health claims' — it's very specific, validating only 1–2 application domains.
Chapter 4
Creatine · the brain story
Creatine · the brain story
'Creatine is only for muscle' is 20th-century thinking. Over the past 20 years, neuroscience has steadily pushed it into the brain — and for learners and chronic mental workers this is the most frequently missed piece of real evidence.
Why it's chemically plausible:
Brain tissue also runs a PCr → ATP buffering system, using the same enzyme set (CK) as muscle, just with a different supply curveAbout 5% of body creatine sits in the brain — small in absolute terms (~6–8 g) but densely packed in neurons and astrocytesThe brain is metabolically sensitive: 2% of body mass but 20% of energy use — any ATP shortfall immediately translates into cognitive symptoms (attention drop / longer reaction times / more working-memory errors)
Several physiological states with depressed brain energy reserves show creatine's benefits most clearly:
Sleep deprivation: acute drop in brain ATP storesStrict vegetarianism: almost no dietary creatine, low baseline brain PCrAging: declining mitochondrial efficiency reduces brain PCr synthesisAcute cognitive stress (exam crunch, long coding sessions, clinical call shifts): short-term high cognitive load
This isn't a 'brain pill' — it's an extra reserve when brain adenosine triphosphate: The cell's universal energy currency — almost everything that costs energy spends it. is under pressure, the same logic as muscle.
Why it's chemically plausible:
Brain tissue also runs a PCr → ATP buffering system, using the same enzyme set (CK) as muscle, just with a different supply curveAbout 5% of body creatine sits in the brain — small in absolute terms (~6–8 g) but densely packed in neurons and astrocytesThe brain is metabolically sensitive: 2% of body mass but 20% of energy use — any ATP shortfall immediately translates into cognitive symptoms (attention drop / longer reaction times / more working-memory errors)
Several physiological states with depressed brain energy reserves show creatine's benefits most clearly:
Sleep deprivation: acute drop in brain ATP storesStrict vegetarianism: almost no dietary creatine, low baseline brain PCrAging: declining mitochondrial efficiency reduces brain PCr synthesisAcute cognitive stress (exam crunch, long coding sessions, clinical call shifts): short-term high cognitive load
This isn't a 'brain pill' — it's an extra reserve when brain adenosine triphosphate: The cell's universal energy currency — almost everything that costs energy spends it. is under pressure, the same logic as muscle.
Evidence tiers · who responds
Sandkühler 2023 BMC Nutrition systematic review (16 RCTs) and Avgerinos 2018 Exp Gerontol meta (281 healthy adults) are the two most authoritative brain-creatine reviews. Conclusions tiered by effect strength:B-tier evidence (multiple consistent RCTs):
Strict vegetarians / vegans — Rae 2003 (Proc R Soc B, 45-person crossover): 5 g creatine × 6 weeks significantly improved working memory and intelligence tests (Raven matrices); the lower the baseline, the bigger the improvement. The classic brain-creatine RCT.Sleep-deprived states — McMorris 2006 (*Physiology & Behavior*, 36 h sleep deprivation + mild exercise): creatine preserved situational awareness, complex reaction time, and mood. The follow-up McMorris 2007 (*Psychopharmacology*) showed smaller and less consistent effects on random number generation / central-executive subtests (these are *two different papers* — don't conflate); Cook 2011 (*NRF*) partially replicated in rugby players.Acute cognitive stress — Watanabe 2002 et al.: during long mental tasks, creatine groups showed shorter reaction times and lower error rates.
C-tier evidence (single RCT or small samples):
Elderly cognition — Roschel 2021 (Nutrients review): several small studies show short-term memory and reaction-time gains in 65+ adults, more pronounced when paired with resistance training; meta-level evidence is still softMild concussion and traumatic brain injury (TBI) recovery — Sakellaris 2006 and follow-on pediatric TBI studies show faster recoveryDepression adjunct — a single RCT (Lyoo 2012, JAMA Psychiatry) showed faster and larger improvement in women with MDD on SSRI + creatine 5 g/d
Healthy young omnivores with adequate sleep: weak but not zero. Avgerinos 2018 (*Exp Gerontol*, systematic review of 6 RCTs in healthy adults) concluded that **creatine *may improve* short-term memory + intelligence / reasoning**; effects on attention, executive function, and reaction time were inconsistent. This is not an overall-neutral finding — it is a positive signal on memory + reasoning, with evidence thin elsewhere. Honest conclusion: if you eat enough meat/fish, sleep 7–8 h, and aren't training, supplementing creatine purely for brain ROI is poor.
Daily learners — should you?
This is the question users care about most, so let's give the honest answer plainly. Short version: it depends on which bucket you fall in.Strongly consider supplementing (5 g/day):
Vegetarian / flexitarian / almost no red meat or fish — brain creatine baseline really is lower; Rae 2003 is the gold-standard RCT, with a noticeable and perceptible effect (medium gain on Raven matrices)Chronic sleep deprivation (< 6 h on 4+ days/week) — acute tests show a real protective effect, but it's not a substitute for sleep; it's a buffer that softens the collapse40+ years old + heavy cognitive load + concurrent resistance training — multiple studies show synergy in older adults; you'd benefit from training anyway, the brain effect is a free bonusPregnancy / chronic postpartum fatigue + dietitian sign-off — weak evidence but safeMDD on SSRI treatment + psychiatrist sign-off — supported by Lyoo 2012 and follow-on single RCTs
Worth supplementing but the brain benefit is weak (you're buying it for muscle; the brain is bonus): strength / power training + healthy young omnivore — the main gain is in muscle; the brain gets a barely perceptible working-memory bump.
Truly not necessary (save your money):
Healthy young adult + omnivore with plenty of meat/fish + 7–8 h sleep + no training plan — brain PCr is already near saturation, no stressor reveals the creatine effect; 5 g/d will likely produce no subjective change, and objective effect sizes are near 0'Loading up the week before the gaokao / exam' — that's not how it works. Creatine takes ~4 weeks to saturate; pre-exam loading is pointless and it isn't a stimulant (that's caffeine's job)
Practical guide for learners:
1. Get the basics right first: sleep ≥ 7 h, 30 min of moderate exercise daily, ≥ 0.8 g/kg protein, 5 servings of fruits/vegetables. These have 10× the ROI of any supplement
2. If you've done all that and still want to try: 5 g/day for 4 weeks, then journal your subjective focus and reaction-time changes
3. Don't pay extra for 'brain creatine / nootropic versions' — chemically identical to plain monohydrate, just marketing language
4. No buzz / no excitement is normal — creatine isn't a stimulant; the 'I feel smarter' rush you might expect basically won't happen; the real change (if any) is silent — shorter reaction times and fewer test errors
Chapter 5
Who benefits
Who benefits
The 'who should use it' question is more useful to subdivide than 'does it work':
Strongly benefit:
Strength / power athletes: weightlifting, sprinting, soccer, basketball, climbing, CrossFitStrict vegetarians / vegans: low baseline PCr, very pronounced responseElderly + resistance training: creatine alone is weak, but 'creatine + strength training ≥ 2×/week' is one of the rare B-evidence combinations for sarcopenia (Chilibeck 2017 meta)
May benefit but evidence is weak:
Cognition + sleep deprivation: Rae 2003 RCT shows cognitive gains in vegetarians, smaller in omnivoresConcussion / TBI recoveryPostpartum fatigue / postpartum depression
No reason to bother:
Endurance specialists (marathon, distance running, long-distance cycling): creatine mainly affects short bursts; neutral to slightly negative for endurance (due to added weight)People focused on fat loss: creatine doesn't burn fat and adds 1–2 kg of water weight initiallyHealthy sedentary adults with no training plan: without a training trigger, supplementing creatine alone is near zero effect
Strongly benefit:
Strength / power athletes: weightlifting, sprinting, soccer, basketball, climbing, CrossFitStrict vegetarians / vegans: low baseline PCr, very pronounced responseElderly + resistance training: creatine alone is weak, but 'creatine + strength training ≥ 2×/week' is one of the rare B-evidence combinations for sarcopenia (Chilibeck 2017 meta)
May benefit but evidence is weak:
Cognition + sleep deprivation: Rae 2003 RCT shows cognitive gains in vegetarians, smaller in omnivoresConcussion / TBI recoveryPostpartum fatigue / postpartum depression
No reason to bother:
Endurance specialists (marathon, distance running, long-distance cycling): creatine mainly affects short bursts; neutral to slightly negative for endurance (due to added weight)People focused on fat loss: creatine doesn't burn fat and adds 1–2 kg of water weight initiallyHealthy sedentary adults with no training plan: without a training trigger, supplementing creatine alone is near zero effect
Sex, age, disease
Women respond as well as men: yes — equivalent gains under matched training (Antonio 2021). 'Creatine is a male supplement' is a market myth.Elderly (65+) use the same doses as younger adults, but the relative benefit may be larger — baseline PCr is lower and the synergy with resistance training is more pronounced. Chilibeck 2017 meta (357 elderly, 10 RCTs) showed creatine + resistance training added 1.4 kg lean mass and 6.6 kg upper-body strength over resistance training alone.
Children / adolescents: ISSN considers it safe, but conservative recommendations limit use to elite youth athletes rather than healthy children. Parents shouldn't treat it as a 'growth supplement' — there is no evidence for height effects.
Diabetics: standard doses are safe; creatine doesn't affect HbA1c and requires no adjustment.
Kidney disease / chronic renal failure: not recommended. Research shows creatine doesn't damage healthy kidneys, but people with existing CKD are hard to monitor — serum creatinine is a creatine metabolite, so supplementation makes eGFR appear to fall artifactually and confounds clinical judgment.
Pregnancy / lactation: limited data — use cautiously. Not a contraindication, but no safety RCTs.
On anticoagulants / antiplatelets: very limited research on co-use with certain NSAIDs; caution at high doses.
Chapter 6
Dose, timing, form
Dose, timing, form
Creatine is the rare supplement whose dosing is boringly clear.
Form: creatine monohydrate — ISSN explicitly notes it is cheaper, more effective, and safer than every other form (HCl / ethyl ester / kre-alkalyn / buffered). 80% of 'next-generation creatines' on the market are marketing, not innovation.
Two loading paths:
Path A · Fast loading: saturation in 7–10 days — Days 1–5 at 20 g/day in 4 doses (5 g × 4), then 3–5 g/day maintenance from Day 6Path B · Slow loading: no rush, saturation in 28 days — 5 g/day from the start, maintained
Both paths reach the same total muscle creatine level after 4 weeks. Fast loading may cause mild GI upset (bloating / loose stool); slow loading does not. Most people choose B.
Timing: post-meal with carbs + protein is absorbed best — insulin helps move creatine into muscle. Post-workout is theoretically slightly better but the difference is trivial. Fasted, morning, or pre-bed all work — long-term saturation is what matters, single-dose timing is a small detail.
Form: creatine monohydrate — ISSN explicitly notes it is cheaper, more effective, and safer than every other form (HCl / ethyl ester / kre-alkalyn / buffered). 80% of 'next-generation creatines' on the market are marketing, not innovation.
Two loading paths:
Path A · Fast loading: saturation in 7–10 days — Days 1–5 at 20 g/day in 4 doses (5 g × 4), then 3–5 g/day maintenance from Day 6Path B · Slow loading: no rush, saturation in 28 days — 5 g/day from the start, maintained
Both paths reach the same total muscle creatine level after 4 weeks. Fast loading may cause mild GI upset (bloating / loose stool); slow loading does not. Most people choose B.
Timing: post-meal with carbs + protein is absorbed best — insulin helps move creatine into muscle. Post-workout is theoretically slightly better but the difference is trivial. Fasted, morning, or pre-bed all work — long-term saturation is what matters, single-dose timing is a small detail.
Cycling myth
'Creatine should be cycled — 4 weeks on, 4 weeks off' is a 1990s gym myth with no scientific basis:After stopping, PCr stores gradually fall back to baseline over 4–6 weeksThere is no risk of 'shutting down endogenous synthesis' (internal synthesis is not suppressed)Cycling delivers zero health benefit — it just wastes 4 weeks of saturation
The right approach is continuous 3–5 g/day, no breaks. The ISSN position explicitly states long-term use up to 5 years (and 30 years for some) shows no safety signals.
Common myths, point-by-point against the data:
'Creatine damages kidneys': it doesn't damage healthy kidneys — 30 years of research found no evidence. Not recommended in existing CKD (eGFR monitoring interference, not direct kidney damage)'Hair loss / balding': sourced from a small 2009 rugby-team study showing DHT rose ~56% short-term, but 12 follow-up studies failed to replicate it, and there's no follicle-level evidence. Current consensus is a very weak association; people worried about hair loss can choose other supplements to avoid the mental load'Water retention / bloating': it's intracellular water rise (good — into muscle cells), not subcutaneous edema. A 1–2 kg water-weight gain short-term is expected'Causes dehydration / cramps': meta-analysis shows the opposite — creatine improves heat tolerance and reduces cramping'Muscles shrink when you stop': half true. The 1–2 kg of water gained from creatine disappears when you stop. Real hypertrophy (from training) does not disappear the moment you stop
Chapter 7
Why it's the rare 'clean' supplement
Why it's the rare 'clean' supplement
Creatine sits in an unusual position in the supplement world — it doesn't behave like a supplement:
The drug-like parts:
Single, well-defined molecular structure (not a 'mixed extract')Mechanism clear at biochem-textbook depthDosing studied to the point of boredomISSN / IOC / WADA all explicitly accept it (zero sport-ban risk)Safety: 30+ years of human follow-up with no signals
The not-like-a-drug parts:
No prescription needed, cheap (< ¥300 per year)Naturally present in food (red meat / fish)Effect is mild rather than dramatic
That's why creatine is often called 'the cheap drug' or 'the least supplement-like supplement' — its existence throws light on the rest of the supplement market: most other supplements have evidence far weaker than creatine, yet sell for more and market more aggressively.
The drug-like parts:
Single, well-defined molecular structure (not a 'mixed extract')Mechanism clear at biochem-textbook depthDosing studied to the point of boredomISSN / IOC / WADA all explicitly accept it (zero sport-ban risk)Safety: 30+ years of human follow-up with no signals
The not-like-a-drug parts:
No prescription needed, cheap (< ¥300 per year)Naturally present in food (red meat / fish)Effect is mild rather than dramatic
That's why creatine is often called 'the cheap drug' or 'the least supplement-like supplement' — its existence throws light on the rest of the supplement market: most other supplements have evidence far weaker than creatine, yet sell for more and market more aggressively.
Buying guide · China
Only buy:Creatine monohydrate: ingredient list shows only this, optionally with a small amount of carbs or flavoringReputable brands: Optimum Nutrition (ON Gold Standard), MyProtein, Bulk, BulkSupplements; domestic brands like MuscleTech and Combit also fineCreapure® certification (Germany's AlzChem high-purity ~99.99%) is worth the small premium
Don't buy:
'Micronized creatine': marketing word — standard monohydrate powder is already fine enough'Kre-Alkalyn / buffered / HCl / ethyl ester / nitrate': all cost 2–5× more with no advantage over monohydrate (multiple head-to-head RCTs)'Creatine + 1000 other ingredients pre-workout powder': you don't know the dose; ingredient lists are watery
Price reference:
¥150–300 / kg is a fair range1 kg = 200 days at 5 g/dayAnnual cost < ¥300 — cheaper than any 'brain' or 'anti-aging' supplement, and the evidence is the strongest
Storage: dry, dark, used within 6 months of opening. Don't mix with hot water — creatine slowly degrades to creatinine above 60°C (harmless but wasted). Cold water, warm water, milk, or juice are all fine.