The Power Repair Shake is based on the powerful combination of grass-fed whey concentrate, collagen and l-glutamine which not only builds muscle but also looks after the gut. Athletes for many years have used whey protein to build muscle. Many whey proteins on the market are over-processed and can be damaging to the digestive system leading to ulcers and discomfort. A good quality grass-fed whey is much gentler on the system.