Purpose: Evaluate whether daily intake of Hericium erinaceus (lion’s mane) improves cognitive functions in older adults after 12 weeks.

Methods: In this randomized, double‑blind, placebo‑controlled parallel‑group study, 34 participants over 50 years were assigned to consume 0.8 g capsules of powdered H. erinaceus fruiting body or placebo four times daily for 12 weeks; 31 completed the study. Cognitive performance was assessed at baseline, mid‑point (6 weeks) and end using the Mini Mental State Examination (MMSE), Benton visual retention test, and standard verbal paired‑associate learning test.

Results: Only the MMSE showed a significant improvement in the H. erinaceus group compared with the placebo group across the 12‑week period (interaction P = 0.029). The Benton and paired‑associate tests showed no significant changes between groups. Participants maintained high compliance, and there were no reports of adverse events.

Conclusion: A 12‑week course of lion’s mane mushroom capsules enhanced global cognitive scores and prevented deterioration in older adults, supporting its potential as a safe nutritional strategy for preserving brain health. The authors suggest that hericenones and other compounds in the fruiting body stimulate nerve growth factor and immune pathways, contributing to the observed benefits.