USN Protein Fuel 50 is a delicious ready to drink protein shake.Each serving provides up to 50g of Premium Protein. Protein supports muscle growth and maintenance. Increasing protein intake may be of use to those training to build muscle mass. Adding a shake such as Fuel 50 to your nutritional plan can be a simple and effective way to increase protein intake.USN Protein Fuel 50 are perfect for taking to the gym and consuming after your training programme. It is also a healthy protein snack suitable for anytime of the day or night.