The present invention relates to a drug delivery device for administering a medicinal product to a patient comprising at least one component (2, 8, 10, 12, 14, 15, 16, 17, 18, 20, 22, 24, 26, 28) comprising a material having an additive embedded in the bulk of said component, wherein the additive is adapted to provide a visually perceptible signal when exposed to electromagnetic radiation.