GNC Pro Performance Zinc Magnesium Amino ZMA Complex – For Restful Sleep & Relaxation. Adequate sleep plays a large role in health. Not getting enough sleep has been linked to developing diabetes, heart disease, obesity, lower immunity levels, and depression. Adults need about seven to eight hours of sleep per night. Let’s make the necessary changes to ensure an adequate amount of sleep. on a regular basis. GNC Zinc Magnesium Amino Complex contains hops flower extract, L-Theanine, L-Tryptophan, Vitamin B6, Zinc, and Magnesium as the major ingredients. Magnesium is necessary for nerve function and zinc has a calming and anti-depressant effect. Hops Flower Extract is an age-old traditional remedy to help with sleep problems. L-Tryptophan, L-Theanine & Vitamin B-6 are considered to be sleep supporting amino acids.