amino acid · for chronic fatigue
Creatine
Keeps a reserve of quick energy in your cells, which is the basis for a claim about tiredness.
Say that in clinical terms
Maintains cellular energy reserves by replenishing ATP stores. May reduce perceived fatigue via improved mitochondrial function.
How strong is the research?
1 paper read.
Who was studied: Studied in 45 young vegetarians, who start with less creatine than people who eat meat.
The study measured memory and reasoning in vegetarians. Fatigue was never measured.
How much to take
daily
5 g
Benefits may take 4-6 weeks. Most studied for exercise-induced fatigue but shows promise for chronic conditions.
Before you take it
- No Tolerable Upper Intake Level (UL) has been established by NIH ODS for creatine; it is not classified as an essential nutrient. Doses of 3–5 g/day (maintenance) and up to 20 g/day (loading phase, 5–7 days) have been studied for periods up to 5 years in healthy adults without clinically significant adverse effects.
- Contraindicated with pre-existing kidney disease: creatine elevates serum creatinine, which can confound renal function monitoring and may add stress to already-compromised kidneys.
- Caution when co-administered with diuretics: creatine promotes intramyocellular water retention while diuretics increase fluid excretion; combined use raises the risk of dehydration and renal strain.
- Caution with nephrotoxic drugs (e.g., NSAIDs, aminoglycosides): no controlled interaction studies exist, but additive renal stress is mechanistically plausible.
- Contraindicated in pregnancy and lactation: no adequate safety data exist for these populations.
- Gastrointestinal side effects (bloating, cramping, loose stools) are reported at loading doses (≥10 g/day); occurrence at maintenance doses (3–5 g/day) is rare.
- This trial was conducted exclusively in vegetarians, who have lower baseline brain creatine; the effect size documented here likely overestimates what would be observed in an omnivore-majority user population with already-adequate creatine stores.
What we make of it
The study measured memory and reasoning in vegetarians. Fatigue was never measured.
The detail
The trial tested working memory and reasoning puzzles in vegetarian participants. It did not measure tiredness at any point, so it cannot support a claim about fatigue. For diagnosed chronic fatigue specifically, the evidence is thinner still.