Do caps or stems contain more psilocybin/psilocin?

The caps tend to contain more psilocybin and psilocin than stems.

From Morphological and chemical analysis of magic mushrooms in Japan :

..... The psilocin/psilocybin contents in P. cubensis were in the range of 0.17–0.78%/0.44–1.35% in the cap and 0.09–0.30%/0.05–1.27% in the stem. Hallucinogenic alkaloids (psilocin and psilocybin) have a tendency to be contained in the cap more than the stem. Our results are in agreement with the findings of Wurst et al. [8] who found lower concentrations of psilocybin in the stem than in the cap of the hallucinogenic fungus, Psilocybe bohemica. P. cubensis samples also had a tendency to contain larger amounts of psilocybin than psilocin. This tendency is consistent with results reported by Bigwood and Beug [4]......

When the data from the above study is  proecessed, it shows that in the samples of the above study, the caps were 30% more potent than stems.



Mushrooms though come with caps AND stems thus it would be a complete waste to only use the caps just because they are slightly more potent.