On: Study finds no detrimental effects of psilocybin i...

[yboris]

I suspect you're thinking of 3.5g amount - which is a typical amount of magic mushrooms to consume. The study is using psilocybin directly.

Wikipedia states "The concentrations of psilocin and psilocybin ... [is] 0.37–1.30% (dry weight) in the whole mushroom".

Assuming about 0.5% concentration, 3.5g of dry mushrooms is about 18mg of psilocybin/psilocin.