Dextrin - cornstarch. That is a filler. You want to stay away from any foot pads that have that in it... they can do over 50% "dextrin" and the pads end up not working. I tried a rip off brand in the beginning but my chiro gave me a sample of the other brand and there was a HUGE difference. I like them!! My health has been too poor for so many years that it is worth spending about $60 per month to feel energized and health again.