CreatineAmino Acid

• Short-burst power and strength outputLikely helps

  Creatine monohydrate plus resistance training is among the most-studied ergogenic aids, and the ISSN's 2017 position stand finds it reliably supports short-duration, high-intensity capacity, strength, and power [1].
  
  This is the best-backed claim on the page. Note its scope: seconds-long maximal efforts, not endurance [1]. ^[1]

• Muscle size (hypertrophy)Possibly helps

  Here the picture breaks up. A 2023 meta-analysis of imaging-confirmed regional hypertrophy found a pooled effect of just SMD 0.11 (95% CrI −0.02 to 0.25) over training alone [7].
  
  A 2025 UNSW-led 12-week RCT in 54 people found no muscle-gain advantage from 5 g/day over resistance training with placebo [9].
  
  A 2022 narrative review likewise found trials where creatine added nothing to strength, hypertrophy, or sport performance beyond the training itself [6].
  
  The ISSN position stand and the older literature describe creatine as strongly ergogenic [1]. Both readings are in print, and neither side has conceded. ^[7]

• Memory, concentrated in older adultsPossibly helps

  A 2023 meta-analysis of memory in healthy people found an overall SMD 0.29 (95% CI 0.04–0.53) [10].
  
  Almost all of it sat in adults aged 66–76 (SMD 0.88). In people aged 11–31 the effect was 0.03 and not significant [10].
  
  A 2024 review of 16 RCTs (492 participants) found benefits for memory (SMD 0.31) and processing speed, but none for overall cognition or executive function [5].
  
  Both reviews ask for larger, more robust trials before anyone calls this settled [5][10]. ^[10]

• Fat lossNot shown to help

  Creatine is not a fat-burner and does not suppress appetite. The evidence does not support a direct weight-loss or fat-loss effect [8].
  
  Any indirect help during a diet would come from training harder and holding lean mass, not from creatine raising calorie expenditure [8]. ^[8]

• AGAT and GAMT deficiencyLikely helps

  These are two rare autosomal-recessive disorders that block the body's own creatine synthesis [12].
  
  High-dose oral creatine monohydrate, at reported case-series regimens of roughly 100–800 mg/kg/day, can largely restore brain creatine and improve myopathy and developmental outcomes [12].
  
  Starting in infancy matters. Two AGAT-deficient patients dosed from 4 and 16 months had normal cognitive and behavioural development at ages 10–11 [12].
  
  Those amounts are orders of magnitude above athletic maintenance dosing, and belong to specialist care rather than self-supplementation [12]. ^[12]

• Creatine transporter (SLC6A8) deficiencyNot shown to help

  The third cerebral creatine deficiency syndrome is X-linked and affects cellular uptake rather than synthesis [11].
  
  Oral creatine does not work here, because the defect is in getting creatine into the cell, not in making it [12][13].
  
  It is also the most common of the three syndromes overall, while GAMT deficiency is the most common synthesis disorder [11]. ^[12]

• Global developmental delay
• Intellectual disability
• Expressive speech and language delay
• Autism-like behaviour
• Epilepsy and seizures
• Movement disorders
• Proximal muscle weakness, reported particularly in AGAT deficiency^[11]

• Creatine monohydrateEverything the evidence on this page rests on.

  Elemental content

  The benchmark: best-studied, cheapest, and stable as a dry powder [14]

  Absorption

  A manufacturer analysis found no measurable degradation into creatinine after 3+ years at up to 40°C (104°F) [14].
  
  Dissolved, it is a different story. Days at room temperature are enough to lose potency [14].

  Best for

  Everything the evidence on this page rests on. Newer forms get compared against it, not the other way round [14].

• Creatine hydrochloride (HCl)People who dislike monohydrate's grit or the bloating.

  Elemental content

  Hydrochloride salt, considerably more soluble in water than monohydrate [14]

  Absorption

  A comparative review found a trend toward higher bioavailability and less intramuscular water retention [15].
  
  The same review concluded there is not yet enough evidence that this turns into better strength or performance [14][15].

  Best for

  People who dislike monohydrate's grit or the bloating. Not a performance upgrade on current evidence [14].

• Buffered creatine (Kre-Alkalyn)Nothing the evidence supports.

  Elemental content

  Alkaline creatine synthesized to a pH of about 12 [14][16]

  Absorption

  Marketed as up to 10 times more bioavailable, on the theory that the buffer stops conversion to creatinine before it reaches muscle [14].
  
  A randomized, double-blind head-to-head trial found no such advantage [16].

  Best for

  Nothing the evidence supports. At equal doses it matched plain monohydrate on muscle creatine, body composition, and strength [16].

• Pre-mixed liquid and ready-to-drinkConvenience, at the cost of potency you have no way to verify .

  Elemental content

  Creatine already in solution, so the clock is already running [14]

  Absorption

  In liquid, creatine degrades into inactive creatinine within days at room temperature, faster when warm or acidic [14].
  
  Refrigeration slows it down. Mixing a dose right before drinking sidesteps the problem entirely [14].

  Best for

  Convenience, at the cost of potency you have no way to verify [14].

• Bloating, mostly a loading-phase problem

  True stomach bloating tracks with loading-phase doses of 20–25 g/day, not with 3–5 g/day maintenance [36][3].
  
  The water creatine holds is mainly intracellular, inside muscle cells, rather than under the skin or in the gut [35].
  
  Skipping the loading phase and taking the smaller dose from day one is the usual way around it [3]. ^[36]

• Raised blood creatinine is not kidney damage

  Creatinine is creatine's waste breakdown product, and it is also the marker labs use to estimate kidney function [14][17].
  
  Supplementing creatine can raise measured blood or urine creatinine with no actual kidney injury behind it [17].
  
  If you are having renal bloodwork done, mention that you take creatine. Otherwise a normal kidney can produce an abnormal-looking result [17]. ^[17]

• Kidneys: trials clean, case reports not

  Controlled trials — a systematic review plus RCTs running from 5 days to several years — found no adverse effect at recommended doses on GFR, cystatin C, proteinuria, or albuminuria [20].
  
  Against that sit isolated case reports of acute kidney injury, one in a college-aged athlete on a standard dose [21]. Causality in those reports is disputed.
  
  A 2025 safety review calls creatine monohydrate safe for healthy people at recommended doses, while flagging reduced kidney function, diabetes, or hypertension as risk-raising [22].
  
  That review and Mayo Clinic both advise anyone with an existing kidney condition to speak to a clinician first and have renal function monitored [17][22]. ^[22]

• Parkinson's disease with high caffeine intake

  Mayo Clinic notes one observational study in people with Parkinson's disease who were taking creatine [17].
  
  Those also consuming more than 300 mg/day of caffeine showed faster disease progression [17]. That is a single population-specific finding, not a general safety signal. ^[17]

• Caffeine

  There is no pharmacokinetic interaction — neither substance changes the other's blood levels [18].
  
  Whether caffeine blunts creatine's ergogenic effect is mixed. Some studies found blunting during a loading phase, mainly around 5 mg/kg of caffeine, and the evidence is described as weak [18].
  
  Once loading is finished, pre-exercise caffeine did not blunt the benefit, and in some studies enhanced it [18].
  
  Early studies mixing creatine into hot coffee or tea found no inhibition. A normal cup carries far less caffeine than 5 mg/kg [18]. ^[18]

• Loop diuretics such as furosemide

  Creatine pulls water into muscle cells, while loop diuretics drive fluid and electrolyte loss the other way [37].
  
  A professional drug-interaction reference flags the pairing for dehydration and low potassium, advising monitoring plus adequate sodium and fluid [37].
  
  This is a monitoring caution, not a demonstrated finding. No dedicated creatine-plus-diuretic trial exists [37].
  
  Worth keeping separate from creatine alone: controlled studies in hot, humid conditions found no detrimental effect on hydration or thermoregulation, even starting dehydrated [22]. ^[37]

Creatine comes almost entirely from animal foods — red meat and fish. Plant foods contain essentially none [23][25].

Your body already supplies 1–2 g/day on its own, and an omnivorous diet adds another 1–2 g, for a turnover of roughly 2–4 g/day [17][25].

Raw beef, pork, and venison run about 0.35–0.5 g per 100 g; chicken sits a little lower at 0.35–0.4 g [23].

Fish is comparable or higher. Salmon, tuna, sardines, and cod land around 0.3–0.45 g per 100 g raw, and herring is often cited as the richest source of all [23][24].

Cooking costs you a lot of it. The roughly 1 g in an 8 oz (227 g) raw steak can fall to essentially nothing when cooked well-done [23].

Food is not a realistic route to a supplemental dose. Matching 5 g would take roughly 1–1.5 kg of raw red meat or fish in a single day [23][25].

These are approximate ranges rather than precise values — creatine isn't tracked in USDA FoodData Central, so beef alone is cited anywhere from 4.5 to 5.0 g/kg [23][24].

Vegetarians and vegans measure lower baseline muscle and blood creatine, and a systematic review found supplementation raises their levels at least as much as omnivores' [26].

Consistency beats clock time. Taking the 3–5 g maintenance dose every single day matters far more than which hour it lands in [30].

A 4-week trial in recreational bodybuilders compared 5 g immediately after training against 5 g immediately before [27].

Post-workout produced numerically greater gains in fat-free mass and bench-press strength, but the group-by-time interaction did not reach significance [27].

A separate study in elite female handball players found no meaningful difference between morning and evening dosing [29]. Creatine sits in muscle and is available whenever it's called on.

So pre- versus post-workout stays an open question. Somewhere within about an hour of training, and on rest days whenever you'll actually remember [29][30].