A method of time delayed reduction in the molecular weight of polymers in a viscosified fluid and a method of time delayed breaking of viscosified fluids through treatment of the viscosified fluid with a viscosity breaking composition. The viscosity breaking composition is formed from a peroxygen compound, a peroxygen inhibiting agent and a peroxygen catalyzing agent, where the relative concentration of the components determines the duration of the a time interval require for breaking the viscosified fluid.