The present disclosure relates to a pharmaceutical composition for providing phosphorus to an adult or pediatric patient, wherein the composition is an aqueous solution of sodium glycerophosphate which by virtue of an improved process for producing the active pharmaceutical ingredient and the pharmaceutical composition is characterized by a low amount of free phosphate, a low amount of SGP-related substances and by a low amount of aluminum. The pharmaceutical composition is used in clinical nutrition, preferably in the preparation of nutritional formulations by compounding. The compositions can further be used for preventing or correcting phosphorus deficiency (hyperphosphatemia) in said adult or pediatric patients.