Iron vs Lion's Mane

for cognition

Stronger evidence: tie

Stronger effect: Iron

Safety: No notable interactions recorded for either.

For cognition, the two are evidence-matched; the difference is in effect and safety.

Iron

grade C low certainty

improves attention/cognition when iron deficiency is present; no benefit if replete

18–65 mg/day, iron-deficient adults

Lion's Mane

grade C low certainty

early, small studies suggest a modest cognitive effect

~1 g/day, adults
sources: PMID:20000115 · PMID:00000010