The science behind it
Psilocybin, the active ingredient in psychedelic mushrooms is around 100 times less potent than LSD. It would take a dose of about 0.2-0.5 grams for you to start feeling its effects, but this generally varies person to person. A dose of around 1-2.5 grams is considered moderate, and if taken orally, normally produces effects that last anywhere from 3-6 hours.
When you ingest psilocybin, it gets metabolized by your body into psilocin, which are both responsible for the psychedelic effects of shrooms. Both psilocybin and psilocin bind to special receptors in the brain called serotonin receptors. Serotonin is called the happy chemical of the body because when bound to these receptors, it triggers a feeling of well-being and happiness. In mice, psilocybin has a strong effect in brain receptors in areas that are responsible for sensory experiences. This is a possible explanation for the psychedelic effects of mushrooms such as “hearing colors” and “tasting sounds” as well as other altered sensory experiences.

Dosages and effects
Note: Everyone has a different tolerance to substances and effects might vary from person to person. The following data is by no means comprehensive, and might change as more reliable information becomes available.

Benefits and Risks of Shrooms