not true, well for me not true. i used to make my protein shakes at night then take ZMA 1 hr after and it worked fine.
Calcium blocks the absorption of ZMA! If I could post some links I would show some information about ZMA to prove it to you. It may be working for you but is not near as effective as it could.
Wikipedia; The proportion of ingredients generally used in products is 20-30 mg zinc, 400-500 mg magnesium and ~10mg B6. According to the label directions, ZMA should be taken before bed on an empty stomach (2 hours after eating your last meal and at least 30 minutes prior to any other supplements). The product should not be taken with calcium (cheese,milk,etc.), the reason being that calcium blocks the absorption of zinc.
From Interhealth Neutraceuticals;
ZMA; ZMA
a unique, powerful non-steroidal vitamin-mineral support formula to help promote testosterone and insulin-like growth factor levels formulated to enhance muscle strength, endurance, healing, recovery and growth
The recommended daily dose of ZMA® is three capsules (808 milligrams ZMA® per capsule) for men and two capsules for women taken on an empty stomach 30-60 minutes before bedtime. The reason for this is that healing, recovery, tissue repair and muscle growth are maximized during sleep.
Additional Recommendations
Since calcium interferes with the absorption of zinc and magnesium, it is recommended that ZMA® not be formulated with calcium-based excipients nor taken with dairy products or other calcium-containing foods or supplements. For additional information on dosing, follow manufacturer's recommended use printed on the label and/or talk to your healthcare professional.
I've thought of trying ZMA but being I take casein protein at night it would be a waste and I don't see any benefit from this product to take this instead of protein at bedtime. I suppose if you are taking a fast acting protein that is fully digested within an hour then ZMA would be fine. Other than that ZMA seems stupid to take on a workout day when protein is needed during the night.