Power-over-Skin: Full-Body Wearables Powered by Intra-Body RF Energy (2024)

I don’t know if taking energy from the body is a good idea. The laws of thermodynamics will require you to compensate. Also playing with very complex systems like a human body, neglecting what the side effects might be, is unwise on a good day.

Did you read even the first paragraph of the link? This is about using skin as a medium of power distribution to devices, not harvesting power from the human body. No hand-wringing required.