P.S. I just tried doing a pendulum for testing supplements/products... was suprised at how well it worked. since i didn't trust it i tested it a bit and it seems to work. its cheaper than going to a person that does kinesiology... i just used a wooden one, they cost about $15 bucks. just thought i'd pass that on.
the only trick is that in order for it to work, your body has to try the supplement first. then it works by saying 'supplement x is good for my body' and there will either be no energy to move the pendulum, or it'll move back and forth, (which is a no answer). for the statements that are true, a yes answer, the pendulum will go around in a circle.