Lion’s Mane mushroom (Hericium erinaceus) is the most important neuroplasticity compound available through supplementation—its dual hericenone and erinacine mechanism stimulates NGF and BDNF, supporting the structural health of the cholinergic neurons that every other cognitive enhancement compound depends on. This complete guide covers the mechanism, the Mori 2009 RCT (including its striking withdrawal reversal), the Docherty 2023 acute effects trial in healthy adults, the fruiting body vs mycelium quality debate, and the dosing protocol with honest onset timeline expectations.