The emerging research area of intra-body communication (IBC) will foster personalized medicine by enabling interconnection of implanted devices that ensure pervasive patient monitoring and characterization. Communication takes place through energy-efficient technologies such as the capacitive coupling (CC) and galvanic coupling (GC) techniques, which enable body-area communication without wiring; however, the relative novelty of such communication methods means their modeling is still incomplete. This paper focuses on channel characterization of the human body, directly comparing for the first time CC and GC techniques in both wearable and implantable configuration. Experimental data are considered to evaluate the measured impulse response in both ex-vivo chicken tissue and in-vivo human tissue in a frequency range up to 100 kHz. Pseudorandom noise (PN) sequences are transmitted in baseband and a correlative channel sounding system is implemented to evaluate the channel impulse and frequency response through real measurements. Experimental results demonstrate that the channel is relatively flat in the frequency range of interest, which simplifies the design of a transceiver suitable for intra-body networks (IBNs).