In this paper we present the finite element method (FEM) study of a capacitive intrabody communication (IBC) system. We analyze current density distribution at the frequencies of 100 kHz, 1 MHz, and 10 MHz. We investigate the ratio between the capacitive and resistive current density component inside the human body and the influence of skin humidity, as well as the electrode size on the total current density distribution. We showed that the highest total current density is achieved inside the muscle tissue, and that the total current density increases with frequency, skin humidity and the size of the excitation electrodes. The surface potential shows the same trend and is in order of microvolts. At the frequency of 100 kHz the safety limits on the total current density are exceeded for wet skin and for larger electrodes. At the higher frequencies (1 MHz and 10 MHz) maximum allowed current density is not exceeded.