To be honest, this protein did do a good job in maintaining muscle. It did what it was supposed to do, just as it says on the label. However, I can say too that Re-Grow does have a tendency to sit in your stomach. What I mean by this is when I ear breakfast and I have a protein shake it tends to make me feel a bit bloated and it somewhat makes me want to go to the bathroom, but that's just me. I can say that the double chocolate taste is probably the best tasting protein that I ever drank. as for its actual work, it does increase recovery time. If I benched 180lbs on Monday and take it right after my workout the muscle recovery is good enough that I can be able to do a triceps workout the next day without being too sore. In the long run this is a great tasting protein and it does do what it states and help rebuild and grow muscle.