Iron vs Creatine

for energy / fatigue

Stronger evidence: Iron

Stronger effect: Iron

Safety: No notable interactions recorded for either.

For energy / fatigue, Iron has the stronger evidence grade.

grade A high certainty

reliably reduces fatigue when iron deficiency / IDA is present; no benefit when iron-replete

18–65 mg/day, iron-deficient adults (esp. menstruating women)

grade C low certainty

may reduce mental fatigue, especially under sleep deprivation or stress

3–5 g/day, adults

sources: PMID:10000007 · PMID:20000106