Motivated by the recent experiment (Lopes et al. in Phys Rev Lett 119:190404, 2017) with a homogeneous Bose gas, we investigate a homogeneous dilute Bose gas to calculate the quantum depletion density. By means of the Cornwall–Jackiw–Tomboulis effective action approach within an improved Hartree–Fock approximation, the condensed fraction is recovered in an alternative theoretical approach and compared with corresponding findings in experimental data. A good agreement in the extremely small region of gas parameter is demonstrated. Furthermore, the ground state energy is also reattained and discussed.