ZMA is a trademarked compound containing zinc and magnesium. This compound is often included in other
"recovery" supplements, and it may be the best such bodybuilding aid since creatine and glutamine. ZMA
not only helps you recover from training, but may also help you sleep better, particularly when it's
combined with other supplements, such as theanine.
It is suggested that you take ZMA on an empty stomach primarily to avoid interactions with other nutrients. Receptors in your body preferentially choose one mineral over another. Typically, calcium is absorbed by your body ahead of zinc and magnesium. That isn't to say that if you take ZMA with food, or with calcium, your body won't absorb any of the ZMA. The label recommendation stems from the fact that research and experience indicate ZMA is more effective in the absence of these other nutrients. If you eat all day long and right before you go to bed, though, chances are that your stomach is never empty. In that case, it may be best to take ZMA between the last two meals of the day. Let's say you eat a solid food meal at 8 PM, then have a protein shake at 10 PM, and you go to bed shortly thereafter. Try taking ZMA at about 9:30, when your stomach is relatively empty. This will give your body a chance to absorb more of the ZMA than if you took it with your protein shakes, which often are high in calcium.
You could take recovery supplements, such as ZMA, at another time of day. However, many people say that ZMA makes them sleepy no matter what time of day they take it. For this reason, your best bet is to take it late at night, even though you may still have some food in your gut.
As mentioned before, ZMA is great for bodybuilders seeking enhanced recovery and muscle gains. In a 1999 study conducted by L. Brilla of Western Washington University, it was found that supplementing with ZMA on a nightly basis significantly increased free testosterone, growth factor (IGF-1) levels and muscle-strength gains in NCAA football players. Zinc also influences hormonal regulation of cell division, specifically with growth hormone and IGF-1.