A 12-Week, Randomized, Double-Blind, Placebo-Controlled Clinical Trial of Gastrodia elata Extract for Memory Support in Adults with Subjective Memory Complaints

Background/Objectives: Subjective memory complaints (SMCs) represent an early window for cognitive intervention; however, no approved pharmacological treatment exists at this stage. Gastrodia elata is a traditional medicinal plant, and preclinical studies suggest that it may influence synaptic plasticity, neurotrophic signaling, and neuroinflammatory pathways involved in memory; however, human evidence remains limited. Methods: This study was a randomized, participant- and assessor-blinded, placebo-controlled clinical trial in which the Clinical Research Coordinator, statistician, physician, and participants remained unaware of group assignment throughout the study period. Eighty adults with normal objective cognitive function and subjective memory complaints were randomized; 76 participants were included in the full analysis set (36 G. elata, 40 placebo) and all 80 in the safety set. Results: The prespecified primary outcome showed a small between-group difference in MoCA-K total score change: G. elata 0.72 ± 1.34 vs. placebo 0.13 ± 1.07 (between-group p = 0.034). Exploratory secondary analyses showed significant differences in MoCA-K delayed recall, K-MMSE total, K-MMSE memory recall and BDNF, whereas Digit Span and IL-6 did not differ significantly between groups. No serious adverse events occurred. The trial was retrospectively registered in CRIS (KCT0011966) on 12 May 2026. Conclusions: These findings provide preliminary evidence that G. elata supplementation may support selected cognitive outcomes in adults with SMCs, although the clinical relevance requires confirmation in larger, prospectively registered trials. Further studies incorporating neuroimaging and prespecified biomarker analyses are warranted to determine whether the observed cognitive findings are accompanied by objective changes in brain function or circulating biomarkers.