FDTD simulations and experimental B1 mapping at 3T and 7T demonstrate that multi-loop coils (MLCs), i.e. coils made of small loops in series, provide a significant transmit efficiency boost over conventional loop coils at close distance in sample noise dominated settings. Further away, the performance of MLCs is comparable to single loop coils. The MLC principle brings additional degrees of freedom for coil design and optimization and appears advantageous for single coils as well as individual elements of arrays, especially for applications with large target area and shallow target depth, e.g. skin imaging or high resolution MRI of brain slices.