The paper compares the compressibility of two directly compressible isomalts, galenIQ 720 and galenIQ721, using the energy evaluation of the compaction process by means of the force--displacement profiles. It evaluates the energies for friction, energies accumulated by the tablet, energy of decompression, energy of compaction and plasticity in pure dry binders, in dry binders with lubricants (0.5 and 1% of magnesium stearate and sodium stearyl fumarate) and further in the tableting materials containing the model ingredients acetylsalicylic acid and ascorbic acid. The results of the study have revealed that lower values of the energy for friction and compaction with the identical compression force are found by the substance galenIQ 720, which is therefore better compressible than the substance galenIQ 721.