Multi-component protein refers to protein powders that combine several protein sources in one blend instead of using a single source. These can be, for example, different milk proteins such as whey and casein, or several plant sources such as pea and rice.
In practice, the combination usually pursues one of two aims: either a more balanced digestion speed through fast and slowly available fractions, or a more complete amino acid pattern through complementary plant sources. How strongly the individual components are actually represented is best seen from the list of ingredients, since the name alone says little about the exact ratio.
How to read a list of ingredients sensibly is explained in the guide Reading the ingredients list of protein powder, and the entries Whey protein and Casein offer more on the individual components.
