Ferritin is an ubiqutous iron storage protein that can contain up to 2500 iron atoms per ferritin as an iron oxy-hydroxide with varying amounts of phosphate. Constructed of 24 subunits; all or some of the subunits depending on the type of ferritin, can catalyse the ferroxidase reaction. The ferroxidase reaction is the oxidation of ferrous iron by dioxygen at a specific iron binding site. Depending on the amount of iron, dioxygen can be reduced to hydrogen peroxide or water. Stopped flow spectroscopy combined with multivariant analysis allowed us to dissect the mechanism of oxygen activation and iron oxidation providing component spectra of all the species, rate constants and rate laws. We now have a more nuanced mechanism of the ferroxidase reaction than previously proposed and a better understanding of ferroxidase site recovery as more iron is provided. Our latest results will be presented.