This paper proposes a novel modulo loss suppression scheme employing a theoretical BER formula for multi-user multiple-input multiple-output (MU-MIMO) Tomlinson-Harashima Precoding (THP) systems. The main feature of the proposed approach is to control the constellation distance by using the simple theoretical bit error rate (BER) formula in order to overcome the modulo loss. Behind this proposal, there is an interesting fact that the BER performance is dependent on the influence of both the thermal noise and the modulo loss and that its influence is determined by the constellation distance. In the proposed approach, we newly derive a theoretical simple BER formula for MU-MIMO THP and then find out the optimal constellation distance to suppress the modulo loss. The effectiveness of the proposed scheme is demonstrated in comparison to the traditional MU-MIMO THP with fixed distance by means of computer simulations.