a) providing monofluorophosphate, a source of calcium ions, a source of phosphate ions, and a calcium phosphate stabilising agent, wherein the calcium phosphate stabilising agent comprises full length osteopontin and/or a long N-terminal fragment of osteopontin:

b) mixing said source of calcium ions and said source of phosphate ions together with the calcium phosphate stabilising agent in a liquid medium in order to form a stabilised amorphous calcium phosphate complex;

c) mixing the monofluorophosphate with the source of calcium ions, source of phophate ions, calcium phosphate stabilising agent and/or stabilised amorphous calcium phosphate complex in the liquid medium;

wherein the monofluorophosphate, the source of calcium ions, the source of phosphate ions, and the calcium phosphate stabilising agent are all mixed together in a single reaction where precipitation is prevented;

wherein the monofluorophosphate is mixed with the source of calcium ions, the source of phosphate ions, and the calcium phosphate stabilising agent before formation of the stabilised calcium phosphate complex has completed or has reached an equilibrium point, thereby producing a liquid composition comprising a soluble or at least a metastable stabilised amorphous calcium phosphate and fluoride; and

incorporating the liquid composition into an oral care product.