Ginkgo vs L-Theanine

for cognition

Stronger evidence: tie

Stronger effect: L-Theanine

Safety: Ginkgo has the more serious interaction profile (serious vs minor).

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

Ginkgo

grade C low certainty

no reliable benefit for preventing cognitive decline in large trials

L-Theanine

grade C moderate certainty

improves attention and reduces distraction, especially combined with caffeine

100–200 mg, adults
sources: PMID:00000034 · PMID:20000107