Speed on one task rose, errors rose with it, and recall did not
In 41 healthy adults aged 18 to 45, one 1.8 g dose sped a colour-word task and raised errors on it. Over 28 days, only the placebo group's word recall improved.
What the study found
One task got faster, and placebo won two other measures
Forty-one healthy adults aged 18 to 45 took 1.8g of lion's mane or placebo. An hour after one dose, the lion's mane group was faster on a colour-word naming task. On that same task they made more errors than placebo, and over 28 days only the placebo group's word recall improved.
The caveat · Capsule contents never disclosed
The 28-day stress result that gets quoted came in at p=0.051, just outside the usual cutoff for calling a result real. The authors call this a pilot too small to conclude from. What was in the capsule was described only as a proprietary mushroom complex.