Stefan Toennes

Stefan W. Toennes is a psychopharmacologist whose recent work has focussed on human experimental studies of classic and novel psychoactive compounds. He has co‑authored and contributed to a range of clinical and laboratory investigations — from placebo‑controlled ayahuasca trials and neuroimaging studies of psilocybin to a phase‑1 dose‑ranging study of a vaporised 5‑MeO‑DMT formulation (GH001) and comparative acute‑effects work (e.g., 2C‑B versus psilocybin). His publications also address cognitive outcomes of serotonergic stimulants (including MDMA) and methodological issues in psychedelic research design and reporting.

Through interdisciplinary collaborations with clinical psychiatrists, neuroimagers and forensic/toxicology specialists, Toennes has emphasised rigorous safety assessment, adverse‑event characterisation and psychometric evaluation in psychedelic studies. His contributions span experimental human pharmacology, translational safety appraisal and the identification of persistent psychological and immune‑related effects after psychedelic exposure, informing both early‑phase clinical development and broader debates about risk, methodology and therapeutic promise in the field.