A pharmaceutical composition for
isotope-
selective modulation including at least one
isotope selected from the group consisting of 1H, 6Li, 12C, 10B, 14N, 16O, 17O, 24 Mg, 26 Mg, 28Si, 29Si, 32S, 33S, 39K, 35Cl, 40Ca, 42Ca, 43Ca, 50V, 50Cr, 52Cr, 54Fe, 56Fe, 58Ni, 60Ni, 61Ni, 63Cu, 64Zn, 66Zn, 92Mo, 94Mo, 95Mo, 96Mo, 74Se, 76Se, 77Se, 78Se, 70Ge, 72Ge, 73Ge, 79Br, 85Rb, 107 Ag, 130Ba, 132Ba, 134Ba, 135Ba, and 136Ba, wherein said at least one selected
isotope is enriched to exceed its relative
isotopic ratio found in a naturally occurring sample of the same
chemical element. Methods for its use include investigating the isotopic signatures, intervening with isotopic
fractionation in mammals.