Work out. Be strong. Move forward. 50 g protein per serving derived from milk to help rebuild muscles after exercise. Vitamin D and calcium for strong bones. Notice: Use this product as a food supplement only. Do not use for weight reduction. The Power of Pro Series: Consuming both fast and slow release proteins like those found in muscle milk pro series protein powder supplement provides a more sustained delivery of protein, compared to whey alone. Protein helps support muscle rebuilding, muscle growth, and maintenance of muscle mass. Essential amino acids, including leucine, play role in muscle growth.