l-Lys protects the femora from osteoporotic changes. Bone morphology is assessed by micro x-ray computed tomography. Transverse sections of the femoral diaphyses (A) and three-dimensional reconstructed images of the distal femora (B) from group LP (a), group Ade (b), group Gly (c), and group Lys (d) are shown. In addition to these morphologic changes, bone mineral density (C), porosity (D), and orientation of the biologic apatite (E) demonstrate the bone-protective effects of l-Lys (n=5 in each group in A and B and n=6–7 in each group in C–E). **P<0.01; *** P<0.001 (Dunnett’s test).