Lion's Mane

Lion's Mane is an edible mushroom, yamabushitake in Japanese, and the reason it appears in nootropic stacks is a body of cell and animal work showing neurite growth and neuroprotective effects. That work is preclinical. The human side is two small studies and a lot of extrapolation: 30 Japanese adults aged 50 to 80 took 3g a day of dried powder for 16 weeks and scored better on a cognitive scale, with the gains fading within four weeks of stopping, and a 2023 pilot in 41 healthy adults aged 18 to 45 found faster Stroop performance an hour after a single 1.8g dose and no clear effect on stress at 28 days. Neither has been replicated at scale. Safety looks unremarkable, with normal laboratory results across the trials, and the caution worth naming is mushroom allergy rather than anything dose-related.

Stack Almanac records the extract and dose you are actually taking, since 1.8g of fruiting-body powder and 500mg of an eight-to-one extract are different products wearing the same name on a label.