Source Naturals uses extremely high quality potassium and magnesium aspartate. Source Naturals K-Mag™ Aspartate is an excellent source of energizing nutrition for athletic activity or fast-paced daily living. Potassium is essential for nerve function, muscle strength, and glycogen formation, among other biochemical processes. Magnesium plays a key role in over 300 enzymatic reactions, including those involved in the Krebs cycle (the body's main energy production process), the relaxation of muscle tissue, neurotransmitter activity, and hormone regulation. L-Aspartic acid also plays a vital role in energy production and is a major excitatory neurotransmitter.