Lion's Mane vs L-Theanine

for cognition

Stronger evidence: tie

Stronger effect: L-Theanine

Safety: L-Theanine carries a minor interaction; Lion's Mane has none recorded.

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

Lion's Mane

grade C low certainty

early, small studies suggest a modest cognitive effect

~1 g/day, adults

L-Theanine

grade C moderate certainty

improves attention and reduces distraction, especially combined with caffeine

100–200 mg, adults
sources: PMID:00000010 · PMID:20000107