Inositol-tripyrophosphate is an allosteric effector of hemoglobin due to its ability to cross the plasma membrane of red blood cells and deliver oxygen to solid tumors, by lowering the oxygen affinity of the hemoglobin of red blood cells. The present invention is directed to the use of inositol-tripyrophosphate to reduce hemoglobin's affinity for oxygen in circulating red blood cells. The present invention is further directed to the use of inositol-tripyrophosphate to inhibit angiogenesis and enhance radiation sensitivity of hypoxic tumors. The present invention is further directed to the use of inositol-tripyrophosphate for the treatment of various types of cancers, Alzheimer's disease, stroke and osteoporosis.