sorry to hear about your plight with the zapper.it seems hard to believe that 15 hz could do that to you,21x3 session.don clarks terminator zapper is 15 hz and they say you use it 40 minutes non stop at first minimum,and after that pretty much around the clock,their must of been thousands of people that have done this with no side effects other than a little die off reaction.maybe the 15 hz with the Z4eX handhelds copper tubes are different from the two little copper circles of the terminator zapper.well i hope you get better soon,best wishes...