However, since denaturing can affect the biologic activity of certain peptides, whey concentrate has a theoretical health advantage over isolate. That being said, depending on the process used, whey isolate may still have significant amounts of bioactive peptides. Ion-exchange is a purification process that, while producing the highest concentration of protein, essentially eliminates all bioactive compounds. Micro-filtration techniques, such as Cross Flow Micro filtration, are a more expensive procedure but yield a whey isolate with more intact bioactive peptides. Hydrolyzed whey isolate is whey isolate that has been further broken down, yielding small peptides that are rapidly absorbed into the blood stream. Again, though, this extra processing comes at the cost of destruction of health promoting substances.