The invention relates to a method for incorporating alkali metals or alkaline earth metals in a metal oxide and a metal oxide product. Through contacting an aqueous solution comprising alkali metals or alkaline earth metals with a metal oxide body, drying said metal oxide body and heating the dried metal oxide body at temperature higher than 1000 °C a penetration of alkali metals or alkaline earth metals in the metal oxide body is achieved. Desired release profile of alkali metals or alkaline earth metals can therefore be obtained avoiding the drawback of the prior art.
