Nerve and Muscle Nourishment Promotes Relaxation Fizzy, Lemonade Flavor NOW Magnesium Inositol Relax Powder combines magnesium and inositol, two nutrients that support relaxation and a normal mood. Magnesium is a mineral that is critical for metabolism, energy production, nerve impulse transmission and more. Inositol is a member of the B-complex family that’s found in all cell membranes, especially in the brain and central nervous system, where it plays an important role in neurotransmitter signaling.