Psilocin-O-glucuronide is psilocin with a glucuronic acid group joined to its oxygen. A 2017 review names it the main urinary metabolite and notes that it matters for clinical and forensic testing (Dinis-Oliveira, 2017). The process that makes it is called glucuronidation.
It explains a detail in urine studies. In a 2002 controlled study, adding the enzyme beta-glucuronidase to urine samples roughly doubled the measured psilocin, showing that much of it leaves the body attached to glucuronic acid; the authors concluded this extends the time psilocin can be detected (Hasler et al., 200200278-9)). A 2017 study suggests that psilocin released again from its glucuronide may explain a longer elimination tail in some people (Brown et al., 2017).
These are research figures from small studies, not detection windows, and a 2025 systematic review notes that psilocybin’s pharmacokinetics vary with dose, route and species (Meshkat et al., 2025). How fast any one person forms and clears the glucuronide has not been mapped.
Sources
- Dinis-Oliveira, 2017, Drug Metabolism Reviews
- Hasler et al., 2002, Journal of Pharmaceutical and Biomedical Analysis: renal excretion of psilocin
- Brown et al., 2017, Clinical Pharmacokinetics
- Meshkat et al., 2025, Pharmaceutics
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