Casein is a good pre-sleep protein because its absorbed slowly, providing your muscles with a steady stream of amino acids throughout the night.
I liked Optimum Nutrition’s 100% Natural Casein Protein over the many others that I’ve tried because it didn’t bother my stomach (my stomach is a bit sensitive to dairy-based proteins), and it’s affordable.
I finally settled on Healthy ‘n Fit 100% Egg Protein as my pre-sleep protein, however, as egg is a slow-burning protein too and I try to stay away from dairy as much as possible.
If you’re fine with whey, however, you’ll be fine with casein. Whether you should use casein or egg protein for your pre-sleep snack is up to you. I recommend that you try both for a few weeks and see which you like most.