Creatine

Creatine

Creatine is stored in muscle cells as phosphocreatine — a rapid ATP resynthesis buffer. When a muscle fires, ATP is consumed in milliseconds; phosphocreatine rebuilds it instantly, before slower metabolic pathways can respond. Saturating this pool through supplementation extends the window of high-intensity output before fatigue sets in. For the broader role of muscle as an organ and training principles, see the muscle module. For the full energy system context, see the ATP metabolism module.

The most studied supplement in sports science — over 500 human RCTs. Safe across the full tested dose range. Only form worth using: creatine monohydrate.

Key takeaways

• 3–5g/day creatine monohydrate — no loading required; saturation in ~4 weeks. Monohydrate has 500+ RCTs; no other form has demonstrated superior outcomes
• Strength +5–15% consistently replicated across compound lifts; power output, muscle volume, and recovery all improved
• Brain benefits are real but population-specific — strong in older adults (66–76 years), sleep-deprived, and vegetarians; small positive effect in the largest young-adult RCT (n=123); no reliable large effect in healthy young adults at rest
• Women have 70–80% lower creatine stores than men — supplementation may be particularly important during menses, pregnancy, post-menopause, and for mood support
• Hair loss is a myth — the single 2009 study (n=20) showing DHT increase has never been replicated in 15+ years; a 2025 RCT directly measuring hair density found no effect
• Safe at all studied doses — side effects limited to water weight gain (1–2kg), GI discomfort only at >10g/dose, and expected creatinine elevation on bloodwork (not kidney damage)
• Source matters — only buy Creapure or Creavitalis certified; some bulk sources contain toxic manufacturing byproducts (DCD, DHT)

Creatine Calculator→

---

How creatine works

Your body uses creatine through a simple, fast reaction:

PCr + ADP → ATP + Creatine (catalysed by creatine kinase)

Phosphocreatine donates its phosphate group directly to ADP, regenerating ATP in milliseconds — no oxygen needed, no glucose needed. This is the fastest energy system in your body, but the smallest reservoir.

Endogenous synthesis

Your body makes ~1–2g of creatine per day in the liver and kidneys from three amino acids: glycine, arginine, and methionine. This endogenous production is supplemented by dietary intake — omnivores get an additional ~1–2g/day from food (primarily red meat and fish). Vegetarians and vegans get near-zero dietary creatine, relying entirely on endogenous synthesis.

Total body creatine pool: ~120–140g in a 70kg person (~95% stored in skeletal muscle). Supplementation increases this pool by ~20%, extending the high-power window before fatigue.

The PCr shuttle

Creatine doesn’t just serve as a buffer at the point of contraction. The phosphocreatine shuttle (also called the creatine kinase shuttle) transports high-energy phosphate groups from mitochondria (where ATP is produced) to myofibrils (where ATP is consumed). This spatial energy transport system is particularly important in large muscle cells where diffusion distance between mitochondria and contraction sites is significant.

---

Muscle & performance

• Strength — consistent +5–15% increase in 1RM across compound lifts in the majority of studies
• Power output — faster peak force production; measurable in sprint, jump, and explosive effort tests
• Muscle volume — increased intracellular water retention (cell volumisation) and real lean mass gain over training cycles
• Recovery — lower muscle damage biomarkers (CK, LDH) after hard sessions; faster return to full output
• Endurance buffer — less benefit for pure aerobic work, but helps in high-intensity intervals and repeated sprint protocols

---

Brain

• Cognitive performance under stress — measurable improvements in reaction time, working memory, and mental fatigue resistance, especially during sleep deprivation or hypoxia; benefit is consistent and replicated
• Sleep support — emerging RCT evidence: improved total sleep duration on training days and improved subjective sleep quality during loading; brain phosphocreatine supports ATP recycling during sleep-dependent restorative processes
• Older adults — strong effect (SMD ~0.88) in adults 66–76; brain phosphocreatine declines with age and supplementation partially restores it
• Healthy young adults at rest — evidence is weak; the largest RCT to date (n=123, Sandkühler 2024) found Bayesian evidence for a small beneficial effect on working memory, but this falls below the threshold for a practically meaningful cognitive enhancement in unstressed young adults
• Vegetarians — lower brain creatine baseline means larger cognitive response to supplementation
• Neuroprotection — early evidence for reduced damage markers after mild TBI; preliminary
• Mood and depression — several trials showing benefit as an SSRI adjunct, especially in women; linked to brain energy metabolism

---

Creatine and women

The post previously noted creatine is “equally effective in women” but didn’t expand. Recent evidence (2025) warrants a dedicated section.

Women have inherently lower creatine stores: 70–80% lower endogenous muscle creatine than men, ~20% lower creatine synthesis rate, and 30–40% lower dietary intake (especially in women who eat less red meat). This means the relative benefit of supplementation may be proportionally larger.

Life-stage considerations:

• Menstrual cycle — hormonal fluctuations affect creatine kinetics. Estrogen influences creatine transporter expression. Earlier studies that showed weak results in women often failed to control for cycle phase.
• Pregnancy — early open-label safety trials (2025) are underway. Animal models show creatine protects fetal brain and organs during birth complications (hypoxia). Human safety and efficacy data are still preliminary — not yet a recommendation, but an area to watch.
• Post-menopause — loss of estrogen-mediated creatine support coincides with accelerated sarcopenia and bone loss. Higher-dose creatine supplementation (0.3 g/kg/day) combined with resistance training has shown favourable effects on muscle size, function, and bone markers in post-menopausal women.
• Mood — meta-analyses of creatine as an SSRI adjunct show stronger effects in women, likely linked to sex-specific differences in brain energy metabolism.

---

Doses

Creatine Calculator — muscle, brain, vegan, and sleep-deprived protocols→

• 3–5g/day — muscle, performance, and general health; no loading required, steady-state saturation in ~4 weeks; ~0.1g/kg/day is a more precise estimate
• 5–10g/day — used in cognitive trials showing benefit in older adults, sleep-deprived individuals, and vegetarians; higher dose does not produce large cognitive gains in healthy young adults at rest
• Sleep deprivation context — brain creatine uptake is less efficient than muscle; sleep deprivation trials used loading doses (20g/day × 7 days) or a single high dose (0.35g/kg, ~25g for 70kg); both improved cognitive performance under sleep loss and increased cerebral phosphocreatine; daily doses above the standard 3–5g may provide more brain support when sleep is compromised
• Loading protocol (optional): 20g/day split into 4 × 5g doses for 5–7 days to saturate faster, then drop to maintenance — reaches the same endpoint as gradual dosing ~3 weeks sooner
• Timing: post-workout may have a slight edge over pre-workout for muscle creatine uptake (likely due to increased blood flow and insulin-mediated transport), but consistency matters far more than timing — take it whenever you’ll remember daily
• Absorption is enhanced when taken with carbohydrates or electrolytes (insulin-mediated creatine uptake via the SLC6A8 transporter)

---

Food sources

Food (per 100g raw)	Creatine content	Notes
Herring	~0.7–1.0g	Highest food source
Beef	~0.4–0.5g	Most common dietary source
Salmon	~0.4–0.5g	Also provides omega-3
Pork	~0.4–0.5g	Similar to beef
Chicken breast	~0.3–0.4g	Lower than red meat
Cod	~0.3g	Lean fish
Milk	~0.01g	Negligible
Vegetables / grains	0g	Zero creatine content

A typical omnivore diet provides ~1–2g/day. Vegetarians and vegans get near-zero from food — they rely entirely on endogenous synthesis (~1–2g/day), which means their total body creatine stores are consistently lower. This is why vegetarians show the largest response to supplementation, both for muscle and brain outcomes.

Cooking degrades some creatine (heat converts it to creatinine), so raw/rare preparations retain more — though the practical difference is small.

---

Creatine forms comparison

Form	RCTs	Bioavailability	GI tolerance	Cost	Verdict
Monohydrate	500+	~95%+ (micronised)	Good at ≤5g/dose	~$0.08–0.15/dose	Gold standard
HCl	<20	Higher solubility, but no proven superior absorption	Potentially fewer GI issues at high doses	~$1.00–2.00/dose	No performance advantage over mono
Ethyl ester	<10	Converts to creatinine in stomach; inferior	Poor	Higher	Inferior; avoid
Buffered (Kre-Alkalyn)	<5	No superior uptake demonstrated	No advantage	Higher	No evidence of benefit over mono
Creatine nitrate	<5	Theoretical; unproven	Unknown	Higher	Insufficient evidence

Bottom line: Creatine monohydrate has 500+ RCTs establishing its safety and efficacy. A 2024 head-to-head study found HCl “showed no benefit over monohydrate” for strength, hypertrophy, or hormonal responses. Higher solubility ≠ higher bioavailability in the human GI tract — micronised monohydrate is already ~95% absorbed.

---

Side effects and common concerns

Confirmed side effects

• Water retention — 1–2kg bodyweight increase from intracellular volumisation (water drawn into muscle cells), not fat or subcutaneous bloating. Normalises if supplementation stops.
• GI discomfort — only at high single doses (>10g at once); split doses eliminate this almost entirely. HCl may cause fewer GI issues at high doses due to solubility, but this doesn’t justify its cost premium for standard dosing.
• Creatinine elevation in bloodwork — expected finding in anyone supplementing creatine. Creatine is non-enzymatically converted to creatinine (a waste product filtered by kidneys). This raises serum creatinine, which falsely lowers estimated GFR (eGFR) on standard blood panels. If your doctor sees a low eGFR while you’re on creatine, inform them — cystatin C–based GFR estimation is unaffected and should be used instead.

Hair loss (DHT myth)

This is the single most common concern about creatine. The evidence:

• Origin: one small 2009 RCT (van der Merwe et al., n=20 rugby players) found DHT increased 56% during loading. DHT is linked to male pattern baldness.
• The study did NOT measure hair loss — only hormone levels. DHT remained within normal physiological range.
• Never replicated: a 2021 systematic review of 12 clinical trials found only that one study showed significant DHT changes; all others found no effect on testosterone or DHT.
• Directly refuted: a 2025 RCT measuring actual hair density, follicle health, and hormone levels found no differences between creatine and placebo groups.
• ISSN position stand does not list hair loss as a side effect.

Verdict: there is no credible evidence that creatine causes hair loss. The concern originates from a single unreplicated study that measured hormones, not hair.

Kidney concerns

No adverse renal effects have been found in healthy individuals at any studied dose (up to 30g/day for 5 years). Pre-existing kidney disease is a contraindication — consult a doctor. The ISSN position stand explicitly states creatine is safe for kidneys in healthy populations.

---

Creatine and aging

Beyond brain benefits, creatine has emerging relevance for healthy aging:

• Sarcopenia — creatine combined with resistance training produces greater gains in lean mass and strength in older adults compared to resistance training alone. Given that muscle is the largest predictor of all-cause mortality (see muscle module), this combination is one of the most evidence-supported anti-aging strategies available.
• Bone health — preliminary evidence suggests creatine + resistance training may improve bone mineral density markers in post-menopausal women. Mechanism: cell volumisation in osteoblasts may stimulate bone formation.
• Mitochondrial function — creatine supports the PCr shuttle, which becomes increasingly important as mitochondrial efficiency declines with age. See the ATP metabolism module for full mitochondrial context.

---

Sources

⚠️ Only use ultra-clean certified creatine. Raw material source matters — contaminated creatine exists and is widely sold. Two certified manufacturers: Creapure (Germany, AlzChem) and Creavitalis (Netherlands). Any brand is fine as long as they explicitly state one of these as their raw material source.

• China-sourced raw material contains high levels of dicyandiamide (DCD) and dihydrotriazine (DHT) — ☠️ byproducts of cheap synthesis
• most brands just repack bulk raw material — they do not manufacture it themselves; the raw material source is what matters
• check klatiCHECK for approved sources links

---

Research