Iron vs Creatine
for cognition
Stronger evidence: Creatine
Stronger effect: Creatine
Safety: No notable interactions recorded for either.
For cognition, Creatine has the stronger evidence grade.
Iron
grade C low certainty
improves attention/cognition when iron deficiency is present; no benefit if replete
18–65 mg/day, iron-deficient adults
Creatine
grade B moderate certainty
Meta-analysis of 16 RCTs (n≈492 adults): improved memory, attention, and processing speed; no significant effect on overall or executive function.
5 g/day
sources: PMID:20000115 · PMID:39070254