should also mention that if you get a lot of zinc in your diet, be careful with how much you supplement. Daily recommended dose for men is only 15mg....the ZMA dosage is 30mg zinc (three pills) plus the magnesium and B6.
I get 15mg zinc in my liquid multi, so when i take the ZMA, i usually just do two pills, which would be 20mg. So that puts me at 35mg a day via supplementation, and then whatever else is in diet.
i guess the problem would be copper depletion if you take too much zinc.