Psilocybe cubensis is a species of psychedelic mushroom whose principal active compounds are psilocybin and psilocin. Commonly called shrooms, magic mushrooms, golden tops, cubes, or gold caps, it belongs to the fungus family Hymenogastraceae and was previously known as Stropharia cubensis. It is the most well known psilocybin mushroom due to its wide distribution and ease of cultivation.
The concentrations of psilocin and psilocybin, as determined by high-performance liquid chromatography, are in the range of 0.14–0.42% and 0.37–1.30% (dry weight) in the whole mushroom, 0.17–0.78%, and 0.44–1.35% in the cap, and 0.09 and 0.30%/0.05–1.27% in the stem, respectively.
Individual brain chemistry and psychological predisposition play a significant role in determining appropriate doses. For a modest psychedelic effect, a minimum of one gram of dried Psilocybe cubensis mushrooms is ingested orally, 0.25–1 gram is usually sufficient to produce a mild effect, 1–2.5 grams usually provides a moderate effect, and 2.5 grams and higher usually produces strong effects. For most people, 3.5 dried grams (1/8 oz) would be considered a high dose and may produce an intense experience; this is, however, typically considered a standard dose among recreational users. For many individuals, doses above three grams may be overwhelming. For a few rare people, doses as small as 0.25 gram can produce full-blown effects normally associated with very high doses. For most people, however, that dose level would result in virtually no effects.