Calculations of the energy loss rates from the unified theory are compared with those of other theories (e.g., binary collision theory and the wave theory) to study the accuracy and validity of each theory under various plasma regimes. The unified theory combines the binary collision theory and the collective wave theory, and is more accurate for wide ranges of plasma parameters and for entire interaction ranges (0 ≤ r ≤ ∞). Moreover, the present unified slowing down formalism is not any more complicated than the widely used binary collisional treatment and, consequently, it provides a usable expression in the study of energetic charged fusion product transport in both magnetic and inertial fusion plasmas.