Psilocybe cubensis is probably the most widely known of the psilocybin containing mushrooms used. Its major psychoactive compounds are:
The concentrations of psilocin and psilocybin, determined by high-performance liquid chromatography, were determined to be in the range of 0.14–0.42%/0.37–1.30% (dry weight) in the whole mushroom, 0.17–0.78%/0.44–1.35% in the cap and 0.09–0.30%/0.05–1.27% in the stem.
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. 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. For many individuals doses above 3 grams may be overwhelming. For a few rare people, doses as small as 0.25 grams can produce full-blown effects normally associated with very high doses. For most people, however, that dose level would result in virtually no effects. Due to factors such as age and storage method, the psilocybin content of a given sample of mushrooms will vary. Effects usually start after approximately 20–60 minutes (depending on method of ingestion and stomach contents) and may last from four to ten hours, depending on dosage. Visual distortions often occur, including walls that seem to breathe, a vivid enhancement of colors and the animation of organic shapes. At higher doses, experiences tend to be less social and more entheogenic, often intense and spiritual in nature.
The effects of very high doses can be overwhelming depending on the particular phenotype of cubensis, growth method, and the individual. Psilocybe cubensis mushrooms can come in rather different sizes. It is recommended that one weigh the actual mushrooms, as opposed to simply counting them. People taking MAOIs need to be careful, as psilocybin and psilocin are metabolized by the enzyme monoamine oxidase. A monoamine oxidase inhibitor reduces the body's ability to metabolize psilocin and psilocybin, greatly increasing the intensity of the experience. This can sometimes produce uncomfortable or undesirably intense experiences.
Personal-scale cultivation of Psilocybe cubensis mushrooms ranges from the relatively simple and small-scale PF Tek and other "cake" methods, that produce a limited amount of mushrooms, to advanced techniques utilizing methods of professional mushroom cultivators. These advanced methods require a greater investment of time, money, and knowledge, but reward the diligent cultivator with far larger and much more consistent harvests.
Terence McKenna and his brother Dennis made Psilocybe cubensis particularly famous when they published Psilocybin: The Magic Mushroom Grower's Guide in the 1970s upon their return from the Amazon rainforest, having deduced new methods (based on pre-existing techniques) for growing psilocybin mushrooms and assuring their audience that Psilocybe cubensis were amongst the easiest psilocybin-containing mushrooms to cultivate.