The fluids administered are very effective in restoring hydration levels, but the fluids themselves will be passed through the body within several hours. However, the minerals, vitamins, and other nutrients that are included in IV hydration therapies will be able to provide their respective benefits for anywhere from days, weeks, to even months. The longevity of the treatments heavily depends on what your body needs and if those nutrients are included in the infusion, as those nutrients will provide much longer noticeable results as their levels are heightened.