Evaluating the Neurotrophic Mechanisms of Hericium erinaceus in Mood Regulation: Emerging Evidence and Translational Barriers

Background: The limitations of current monoaminergic antidepressants in treating major depressive disorder (MDD) have driven exploratory interest in neurotrophic compounds. Hericium erinaceus (Lion’s Mane), a macrofungus containing cyathane diterpenoids, has demonstrated putative neurogenic properties in preclinical models. Aims: This narrative review critically evaluates the evidence regarding the neurobiological mechanisms of H. erinaceus and its translational viability in clinical mood regulation. Methods: A targeted review of peer-reviewed literature (January 2010–February 2024) evaluated evidence across a hierarchy from in vitro cell cultures to human pilot trials. Inclusion logic prioritized studies utilizing chemically characterized extracts and validated psychiatric instruments. Results: Preclinical murine data suggest that H. erinaceus upregulates nerve growth factor (NGF) and promotes hippocampal neurogenesis. However, clinical translation remains premature. Existing human trials report exploratory improvements in mood scores but are constrained by small sample sizes, lack of robust blinding, and heterogeneous clinical profiles. Furthermore, clinical human pharmacokinetics, long-term safety profiles, and extract standardization remain poorly characterized. Conclusion: H. erinaceus represents a biologically plausible target for investigation. However, clinical recommendations are currently unsubstantiated. Rigorous, large-scale randomized controlled trials (RCTs) are required to establish causal therapeutic efficacy and isolate specific neurotrophic mechanisms from epiphenomenal psychological effects.