What it is
Lion's mane is Hericium erinaceus; fruiting-body and mycelium products differ in erinacines, hericenones, and beta-glucans.
Core function and why it is studied
Its composition or proposed mechanism makes cognitive function, mood and stress response logical research areas. Studies therefore examine cognitive, mood, and nerve-growth-related measures. That biological connection explains why it is studied; it does not by itself establish a meaningful benefit.
What the evidence means
Human evidence is limited by small samples, short studies, inconsistent preparations, or reliance on surrogate outcomes. The biochemical rationale is stronger than the clinical certainty.
How to compare products
Compare species, fruiting body versus mycelium, extraction method, beta-glucan specification, serving amount, and contaminant testing.