When it comes to building lean muscle, protein is important. But that doesn’t mean you’re restricted to one kind of protein. Instead you could choose a protein blend or complex. These products feature either two kinds of protein (such as whey and casein blends) or non-dairy/animal, non-soy, amino acid complex. In either scenario you still get the benefits like increased muscle protein synthesis and muscle repair, with the combination of fast-slow digesting protein or a complete amino acid complex.