In recent years we witnessed several experiments measuring a large set of observables related
to Cosmic-ray physics with an unprecedented level of precision. In order to be able to fully
exploit this great amount of new data we must act to refine our theoretical predictions. This
can be achieved by building more realistic models of Cosmic-ray Galactic transport. The
DRAGON project has been pursued in order to model Cosmic-rays propagation under realistic
conditions and to allow a comparison with a wide set of experimental data. Studies brought forth
with DRAGON showed how a treatment of Cosmic rays energy losses as realistic as possible is
pivotal. In DRAGON2, the new version of the code, a more accurate, second order scheme for
Cosmic Rays energy losses is implemented. In addition, the new version of the code allows us
to investigate the impact of different models for Interstellar Radiation Field or galactic magnetic
field. We present comparison between the previous energy losses approach and the new one, as
well as validation test by comparing our numerical results with a set of analytical solutions. We
study in particular the interplay of diffusion, reacceleration, and energy losses in a realistic case,
and their impact on leptonic spectrum.