The most studied performance supplement that actually works

Creatine

Creatine monohydrate is the most evidence-backed sports supplement in existence. It increases phosphocreatine stores in muscle, enhancing the rapid energy system (ATP-PCr) used in high-intensity, short-duration efforts. Benefits for strength, power and muscle mass are well-established across decades of research. Emerging evidence also suggests cognitive benefits.

Bottom line

Creatine monohydrate works. The evidence for strength and power output is among the strongest in sports nutrition. It is safe, cheap and effective — the main debate now is whether non-athletes can also benefit cognitively.

Verdict
Strong
Best-supported use
Strength, power output and lean mass in resistance training
Typical dose
3–5 g creatine monohydrate per day (no loading phase required)
Main upside
Exceptionally strong evidence, cheap, safe with decades of research
Main downside
Non-responders exist (~25–30%); may cause water retention (intramuscular, not cosmetic); vegetarians respond more strongly
Caution
People with pre-existing kidney disease — not because it causes kidney damage in healthy people, but as a precaution
What it may help with

Four buckets, no mystery.

Likely helpful
  • Maximal strength and power output
  • Lean muscle mass accrual with resistance training
  • High-intensity exercise performance (sprints, heavy sets)
  • Recovery between bouts of intense exercise
Possibly helpful
  • Cognitive performance, especially in sleep-deprived or vegetarian/vegan individuals
  • Depression symptoms (early evidence, not established)
  • Bone health in older adults combined with resistance training
Unclear / mixed
  • Aerobic endurance performance (weak, inconsistent signal)
  • Cognitive benefits in well-rested omnivores
  • Hair loss acceleration (weak anecdotal concern; DHT mechanism plausible but not confirmed in RCTs)
Probably overclaimed
  • Fat loss directly
  • Equivalent to anabolic steroids or SARMs
  • Kidney damage in healthy people
Evidence scoreboard

Every claimed effect, graded.

Each row grades the claimed effect by strength of human evidence, not mechanism or marketing.

Maximal strength (1RM, multi-rep strength)
Likely helpful
Strong
Hundreds of RCTs confirm consistent improvements in strength outcomes with resistance training.
Lean muscle mass
Likely helpful
Strong
Consistent across meta-analyses; effect partly from increased training volume, partly from cell hydration.
Sprint and power output
Likely helpful
Strong
ATP-PCr system is directly enhanced. One of the clearest performance applications.
Cognitive performance
Possibly helpful
Moderate–low
Strongest signal in vegetarians/vegans and sleep-deprived individuals who have lower baseline brain creatine.
Aerobic endurance
Unclear / mixed
Low
Mixed results; added body weight from creatine may offset marginal aerobic benefits.
Depression / mental health
Unclear / mixed
Early / speculative
Mechanistically interesting; a few small RCTs show signal. Not ready for clinical recommendation.
Consensus snapshot

What the science currently says.

Mainstream

One of very few sports supplements with near-universal endorsement from sports science bodies. International Society of Sports Nutrition rates it as safe and effective.

Enthusiasts claim

Widely used and generally accurately characterised — creatine is one of the few supplements where community understanding broadly aligns with evidence.

Where the gap is

The main areas of emerging debate are cognitive applications, mental health benefits, and optimal protocols for older adults. Hair loss concern exists anecdotally but lacks RCT confirmation.

  • Creatine monohydrate is the most-studied form and there is no replicated evidence that other forms (ethyl ester, HCl, buffered) outperform it.

  • Loading (20 g/day for 5–7 days) saturates stores faster but 3–5 g/day reaches the same endpoint in 3–4 weeks.

  • Vegetarians and vegans typically have lower baseline muscle creatine and see larger performance responses.

  • Creatine does not damage kidneys in healthy people — this myth stems from the fact that creatine metabolism raises creatinine, a kidney biomarker, but this is not the same as kidney damage.

  • The initial weight gain (1–3 kg) on creatine is intramuscular water retention — not fat, not oedema.

Mechanisms

Why it might work.

Mechanism is not outcome. Each mechanism is labelled by how far it has been validated in humans.

Supported in humans

Phosphocreatine resynthesis

Creatine increases the phosphocreatine pool in muscle, allowing faster resynthesis of ATP during high-intensity efforts lasting 1–30 seconds.

Supported in humans

Cell volumisation

Creatine draws water into muscle cells, increasing cell volume — a signal associated with anabolic processes and potentially contributing to muscle protein synthesis.

Supported in humans

Satellite cell activation and myosin synthesis

Creatine supplementation combined with resistance training enhances satellite cell activity and myosin heavy chain expression in muscle.

Supported in humans

Brain creatine and cognitive energy

The brain also uses the creatine-phosphocreatine system for energy buffering. Supplementation increases brain creatine, particularly in those with low baseline (vegetarians, sleep-deprived).

Dosage & timing

How it is used in studies.

Typical studied dose
3–5 g creatine monohydrate per day
Timing
Timing is not critical — consistency matters more. Post-workout timing has marginal evidence for slight advantage
With or without food
Fine with or without food; mixing in liquid (water, juice) is sufficient — no need for specific co-ingestion
Duration used in studies
Benefits begin appearing at 2–4 weeks; full saturation at 4–6 weeks without loading
Upper caution
Higher doses offer no additional benefit once stores are saturated. Very high doses (>10 g/day chronically) are not studied long-term
Beyond sleep
For older adults: some protocols use 5 g/day with resistance training for muscle and bone health. Cognitive protocols typically use 5–20 g/day in acute studies.
Safety

Side effects and interactions.

General

Decades of research in healthy adults show no clinically significant safety concerns at standard doses. One of the most studied and consistently safe supplements.

Possible side effects
  • Initial body weight increase of 1–3 kg (intramuscular water retention, not fat)
  • Gastrointestinal discomfort with large single doses — take smaller divided doses if this occurs
  • Occasional bloating in sensitive individuals
Interactions to watch
  • No established clinically significant drug interactions at standard doses
  • People with kidney disease should use with caution and medical supervision — not because creatine causes damage, but as a precaution given altered kidney function
  • May raise serum creatinine on blood tests — inform your doctor if tested, as this can be misread as kidney stress

This page is educational and not medical advice. If you have pre-existing kidney conditions or are on medication, discuss with a clinician before use.

Best use cases

Who it is actually for.

  • Anyone doing resistance training who wants to make more of it
  • Athletes in power and sprint sports
  • Vegetarians and vegans — who have lower baseline creatine and see the largest responses
  • Older adults combined with resistance training for muscle and functional strength maintenance
  • People who want maximum evidence-to-cost ratio — creatine monohydrate is cheap
Not worth it if...

When to skip it.

  • You are not training — without the training stimulus, creatine effects on muscle are minimal
  • You are paying for 'premium' forms like Kre-Alkalyn or creatine HCl — no replicated advantage over monohydrate
  • You have kidney disease without medical clearance
  • You expect fat loss — creatine does not directly burn fat
Key references

A compact study stack.

A small, curated set — not a literature dump. Each reference comes with a single-line takeaway.

  1. 01
    International Society of Sports Nutrition position stand: creatine supplementation and exercise
    Buford TW et al. · Journal of the International Society of Sports Nutrition · 2007

    Creatine is the most effective ergogenic nutritional supplement for athletes. Monohydrate is the most studied and effective form.

    review
  2. 02
    Effects of creatine supplementation and resistance training on muscle strength and weightlifting performance
    Rawson ES, Volek JS. · Journal of Strength and Conditioning Research · 2003

    Creatine supplementation consistently improves maximal strength and weightlifting performance across studies.

    meta analysis
  3. 03
    Creatine supplementation and brain function: a brief review
    Allen PJ. · Experimental Gerontology · 2012

    Reviews evidence that creatine increases brain phosphocreatine and may support cognitive performance, particularly under metabolic stress.

    review
  4. 04
    Long-term creatine supplementation does not significantly affect clinical markers of health in athletes
    Kreider RB et al. · Molecular and Cellular Biochemistry · 2003

    21 months of creatine supplementation did not adversely affect kidney function, liver enzymes or other clinical markers.

    rct