There are many ways to describe the experience of using magic mushrooms. Mind-altering. Spiritual. Psychedelic. Visual. Reality-bending. Before you reach this point of nirvana, how long do you wait for magic shrooms to kick in? It depends on the dosage. One dose of magic shrooms is equal to 1 gram but may be more for experienced users. When you take magic mushrooms on an empty stomach, it will take 10-60 minutes to onset.