A team of researchers located at Helmholtz Munich reports on a novel function of vitamin K, which is generally known for its importance in blood clotting. The researchers discovered that the fully reduced form of vitamin K acts as an antioxidant efficiently inhibiting ferroptotic cell death. Ferroptosis is a natural form of cell death in which cellular iron plays an important role and which is characterized by the oxidative destruction of cellular membranes. In addition, the team identified FSP1 as the warfarin-insensitive enzyme reducing vitamin K, the identity of which had been postulated but remained unknown for more than half a century.