What affects psilocybin bioavailability: the science of absorption

The main variables affecting psilocybin absorption: gastric pH (fasting: lower pH, faster conversion and absorption); gut motility (stress slows motility, slowing absorption); body composition (volume of distribution affects peak concentration); gut microbiome (differences in conversion enzymes). These factors together can produce 2-3x variation in effective dose from the same amount ingested.

The CYP enzyme variation: some people rapidly metabolize psilocin and others slowly. The slow metabolizers get more intense and longer-lasting effects from the same dose. This is partly genetic and can't be easily changed. If you consistently find that doses affect you more intensely than others report, slow metabolism may be a factor.

Time of day matters somewhat: circadian variation in gastric pH and enzyme activity means the same dose in the morning can have slightly different character than evening. Not a dramatic effect, but one of several factors explaining day-to-day variation.