GNC Zinc Magnesium Amino (ZMA) Complex is one of the best supplements that help reduce tiredness & fatigue and boosts immunity. Include GNC Zinc Magnesium Amino Complex and get the goodness of zinc, magnesium, vitamin B6, amino acids, and Hops flower extract in a single capsule. It is helpful in reducing stress . Lack of sleep is associated with weakened immune system, lower metabolism, diabetes, heart disease and obesity. It supports the immune system, and hence including this supplement can be really helpful in today’s time.