Creatine Statistics: Effects on Strength, Power & Health

Muscle total creatine rose about 20% after 6 days at 20 g a day, and by a similar 20% over 28 days at 3 g a day

31 men took creatine in different amounts and schedules. Loading is faster; a small daily dose gets to the same level in about four weeks.

After loading, 2 g a day kept muscle creatine elevated for a further 30 days; without it, levels were back to baseline 30 days after stopping

Same study. Urinary creatinine excretion rose correspondingly while stores declined.

In 3 of 8 men, 5 days at 20 g a day raised muscle total creatine by only 5-7%, against 15-32% in the other five

Muscle biopsy study. In the low responders phosphocreatine resynthesis after intense contraction did not improve; in the others it rose by 23-53%.

Creatine improved upper-limb strength over placebo: effect size 0.265 for the bench press and 0.317 for upper-limb strength overall

Meta-analysis of 53 randomized trials (563 people on creatine, 575 controls) using exercises under 3 minutes. Meta-regression found no link with age, sex, training status, dose or duration.

With resistance training, creatine added 1.10 kg of lean body mass over placebo; without exercise it added 0.03 kg

Meta-analysis of 35 randomized trials with 1,192 participants; across all studies the gain was 0.68 kg. Men gained 1.46 kg; the 0.29 kg gain in women was not significant.

In older adults doing resistance training, creatine added 1.37 kg of lean tissue mass over placebo

Meta-analysis of 22 trials with 721 men and women, mean age 57-70, training 2-3 days a week for 7-52 weeks. Chest press (SMD 0.35) and leg press (0.24) strength also improved more.

In 357 older adults, creatine plus resistance training increased fat-free mass, chest-press and leg-press 1RM, and 30-second chair-stand performance more than training alone

Meta-analysis of placebo-controlled trials; average age about 64, 12.6 weeks of training. Knee-extension and biceps-curl 1RM did not differ.

Creatine had small but significant effects on body composition (effect size 0.17) and on repeated high-intensity tasks of 30 seconds or less (0.24)

Meta-analysis of 100 placebo-controlled studies. Laboratory tasks (0.25) responded more than field tasks (0.14), and there were no differences between men and women or trained and untrained people.

Creatine does not appear to improve running or swimming performance

Same meta-analysis. The benefit concentrates in short, repeated, laboratory-style efforts such as isometric, isokinetic and isotonic resistance exercise.

Supplementation of up to 30 g a day for 5 years has been found safe and well tolerated in healthy people

ISSN position stand, covering patient populations from infants to the elderly as well. It also suggests a habitual low intake of about 3 g a day may benefit health across the lifespan.

Creatine raised serum creatinine by 0.13 mg/dL on average without changing urea or estimated glomerular filtration rate

Meta-analysis of 19 randomized trials and one crossover study. Creatinine is a breakdown product of creatine, so a higher blood level does not by itself mean kidney harm; the authors call for trials longer than a year.

Dihydrotestosterone rose 56% after 7 days of creatine loading and stayed 40% above baseline after 14 days of maintenance

Crossover trial in 20 college rugby players taking 25 g a day for 7 days, then 5 g a day. Testosterone did not change; the DHT-to-testosterone ratio rose 36%. One small study, not replicated as a hair-loss outcome.

In six randomized trials with 281 healthy people, creatine may have improved short-term memory and intelligence or reasoning; other cognitive results were conflicting

Systematic review. Performance stayed unchanged in young people, and vegetarians responded better than meat-eaters on memory tasks.

Adding creatine to resistance training produced no greater gain in whole-body, hip, femoral-neck or lumbar-spine bone density in adults over 50

Meta-analysis of five trials with 193 participants lasting at least three months. Two individual trials reported bone benefits; the authors call for trials longer than 12 months.

A buffered creatine at its recommended 1.5 g a day did not raise muscle creatine, strength or body composition more than standard creatine monohydrate

Double-blind trial in 36 resistance-trained people over 28 days. The buffered form also produced no fewer side effects.

Vegetarians obtain almost no creatine from their diet; the rest of the body's supply comes from its own synthesis

Creatine is continuously lost as creatinine, so it must be replaced by diet and synthesis; making it draws on glycine, arginine and methionine.

Research on creatine in adolescents is extremely limited, even though it is a popular supplement among adolescent athletes

Brief review of the few available studies. Evidence in adults shows a strong safety profile, but it has not been tested to the same standard in younger athletes.