Glossary map / Chemistry
Psilocybin, psilocin, baeocystin, aeruginascin, the 5-HT2A receptor, blueing and potency: what each chemistry term means and what has been measured.
Psilocybin is the compound magic mushrooms and truffles are known for, but it is psilocin that acts in the brain. The rest of the chemistry vocabulary follows from that pair: how one becomes the other, which related molecules sit alongside them, why the mushrooms turn blue, and why "strength" is so hard to pin down.
Figures on this page describe content measured in laboratories. They are not doses.
A tryptamine alkaloid, chemically the phosphate ester of psilocin. Albert Hofmann isolated it from Psilocybe mexicana in 1958 (Wikipedia). It is stable enough to survive drying, and in the body it is converted into psilocin. Psilocybin is on List I of the Dutch Opium Act, in Annex I of the German BtMG and in Schedule I of the US Controlled Substances Act (drug code 7437).
The active form: 4-hydroxy-N,N-dimethyltryptamine, listed in the Dutch Opium Act as 3-[2-(dimethylamino)ethyl]indol-4-ol. Psilocin is what binds to serotonin receptors and produces the effects. It is less stable than psilocybin and oxidises easily, which is the start of the blue colour in damaged mushrooms. US drug code 7438.
A compound that is inactive itself and becomes active after the body changes it. Psilocybin is the textbook example: phosphatase enzymes remove its phosphate group (dephosphorylation), and what remains is psilocin (Wikipedia).
A compound formed from an acid and an alcohol. Psilocybin is the phosphoric acid ester of psilocin. The word matters legally: UK law covers any "fungus (of any kind) which contains psilocin or an ester of psilocin", a wording that includes psilocybin.
A family of compounds built on the same indole skeleton as the neurotransmitter serotonin. Psilocybin, psilocin, baeocystin, norbaeocystin and aeruginascin are all tryptamines "structurally similar to the neurotransmitter serotonin" (Gotvaldová et al. 2021).
A tryptamine found in smaller amounts in many psilocybin mushrooms, with one methyl group fewer than psilocybin. It is thought to be a step in the biosynthesis of psilocybin (Wikipedia). Its own effects in people are not well studied.
The next step back in the same chain, with no methyl groups on the nitrogen. Like baeocystin, it occurs in low amounts and is regarded as a biosynthetic precursor.
A structural analogue of psilocybin with three methyl groups on the nitrogen (4-PO-TMT). It was one of the six compounds measured in a 2026 comparison of 14 P. cubensis strains (Sharchaton et al. 2026).
A serotonin receptor found on nerve cells, especially in the cortex. Activation of this receptor "is specifically responsible for the hallucinogenic effects of psilocin" (Wikipedia). LSD and mescaline act on the same receptor, which helps explain why their effects resemble each other.
The blue discolouration of psilocybin mushrooms where they are bruised or cut. A 2020 study identified the chemistry: the enzyme PsiP removes the phosphate from psilocybin to give psilocin, a second enzyme, PsiL, oxidises psilocin, and the oxidised units link into chains of 3 to 13 that look blue (Lenz et al. 2020). Blueing is no reliable sign of identity or strength. Dutch-Smart describes blue patches on stored truffles as oxidation.
The time it takes for the concentration of a substance in the blood to halve. For psilocybin, measured as psilocin, the elimination half-life averages 2.1 to 4.7 hours (Wikipedia). The felt effects last longer than one half-life, which is why people are not sober when the visual effects fade.
The breakdown of psilocybin and psilocin during storage and handling. In the 2021 P. cubensis study, the largest losses were in fresh mushrooms stored at minus 80 °C and the smallest in dried material kept in the dark at room temperature (Gotvaldová et al. 2021). Fresh truffles are perishable; Dutch-Smart advises keeping unopened packs in the fridge.
The amount of active compound per unit of material, usually given as milligrams per gram or as a percentage of dry weight. It varies more than labels suggest. In 2026, 14 strains of P. cubensis grown and dried under identical laboratory conditions ranged from 2.62 to 20.65 mg of total tryptamines per gram, a spread of more than 7.8 times, with clear differences between single mushrooms of the same strain too (Sharchaton et al. 2026). For truffles, one study measured 0.6 to 1.7 mg psilocybin per gram of fresh weight (Pellegrini et al. 2013).
A reagent test can tell you whether a sample reacts like psilocybin. It cannot measure how much is in it.
The effects these compounds produce, and the words people use for each phase, are in the experience terms.
For a stay in the Netherlands · adults only
Fresh truffles are legal in the Netherlands. Dutch-Smart, the publisher of this glossary, sells them with test kits and truffle grow kits.
