In the simulation below, you can see that when a wireless headphone antenna is close to the human head, its efficiency drops dramatically. This happens mainly because the human body absorbs and reflects the signals, as it consists primarily of water.

There is nothing to do with the loss itself, but thoughtful choice of antenna type and optimization in the final environment is what can help to work with it. Carefully chosen antenna types can give a radiation pattern that performs best close to very lossy dielectric.