Originally Posted by BendtheBar
Most whey companies get whey from the same limited number of suppliers. From my understanding it arrives as a raw product, and not a product that the protein companies must hit with the ion exchange process themselves.
This is very true to a point. In the main suplier making the raw product it just like any other manufacuring plant. You have diffrent quality product at the end depending on how close to a clean up or after a clean up of there equipment. Then you have anything small amount that are in the fine print on the FDA lable or small enough they don't need to list it, then the sup company adding any fillers and flaverings, this all effect the pureity of the end product. .
IF you looking at protein BV values heres a chart.