Zinc
That zinc is important to the bodybuilder, most in our sport have known for ages, almost instinctively. The science behind the itch is that strenuous exercise tends to deplete body levels of zinc. So bodybuilders have considered zinc one of their most important supplements for a long time. Unfortunately, as those who read my article on milk know, the body prioritizes calcium over zinc and when the two enter the bloodstream simultaneously the zinc is just not absorbed. So why didn't they take it without calcium? The pharmaceutical industry is why. These guys will do anything to make a buck. They are worse than the worst supplement companies. They find a cure for a disease, but hold it back (supposedly for in-house testing) to create hype, so that when it hits the market they can charge outrageous prices (make you think of any supplement company in particular?). But at the same time they try to cut costs on everything. When making pills and caps the cheapest thing to hold the whole thing together is ... calcium!
Check the ingredients on any kind of pill or tab, and you will find that most contain at least some form of calcium (could be dicalcium or something of the sort). That's why no one ever managed to take it without calcium. Even in 50 or 100 mg pills, it never exerted the effect that 30 mg of calcium-free zinc did. The only other way to bind the stuff was a costly procedure called chelation. Chelation fuses a mineral to an amino acid, in this case methionine, but just as easily aspartic acid or aspartame (to form the magnesium aspartate and some ZMAs even contain amounts of zinc aspartate as well, next to the actual ZMA). And voila, one of the most potent supplements is born. I wonder why no one ever thought of this before? I guess they had their eyes closed. Or was it their wallet?