The first Born approximation is used to obtain an analytic expression for the energy loss rate of an energetic charged fusion product, which slows down in dense fusion plasmas, by including the nuclear potential into the stopping power. The analytic expression is used for a comparison with the contributions by Coulomb forces and also with the numerical results obtained from both a Monte-Carlo method and experimental observations. It is found that the difference between the analytic results and the experimental values is not significant while the analytic solution agrees remarkably well with the Monte-Carlo simulations on the ion heating effect.