I use many of them (cheap one) with success and a great impact on sound quality ( an aura given to the chords making them more 3-D).
But i never felt any physiological negative effect.
Many people are electro-sensible...
Perhaps this negative effect can fade away with time ?
I dont know... you will know if you keep them for more ...
Anyone get a physiological reaction from them?
Schumann resonators give me a headache and nausea.
I also tried the Nordost Qpoint, and it had a very similar effect on me.