Arjen Koppen obtained his master in Chemistry, with a specialization in Biochemistry, at the faculty of Chemistry of the University of Amsterdam. He obtained is PhD at the faculty of Medicine of the University of Amsterdam. His PhD research focused on the transcriptional regulation of potential oncogenes and tumor suppressor genes by the oncogene N-MYC in neuroblastoma. Following his PhD, he became a postdoctoral researcher in the department of Metabolic Diseases in the UMC Utrecht, investigating gene regulation by the nuclear receptor PPAR-γ in adipocytes. During this period, he secured a permanent research position.

In 2013, Arjen transitioned to clinical toxicology and joined the Dutch Poisons Information Center (DPIC). In 2021, he became a European Registered Toxicologist, and in 2026 he qualified as an Health Advisor for Hazardous Substances (GAGS, East Netherlands region). Within the DPIC, Arjen is an expert in (1) the toxicology of industrial and household products, (2) paracetamol toxicology, and (3) deliberate self-poisonings.