/b/sixpacksmackdown/posts/what-is-casein-protein-an-in-depth-look-at-casein-whey-proteins-forgotten-brother When someone says they take or drink protein shakes, 99% of the time they're talking about whey protein. Whey is a great, fast absorbing protein, and probably the most popular protein supplement. This brings me to Whey's long lost brother: Ca...en-USTelligent Community 11 Non-Production