Protein draws a lot of discussion, understandably, so my goal with this post is something of an informal and uncomplicated FAQ. Most guys don't seem to know that all of the whey protein in the country first comes from one of five major dairy manufacturing plants, and that most of the familiar manufacturers (Optimum, Pinnacle, etc.) merely package this protein, mark it up, and ship it to distributers like GNC. Some of them further process the protein, isolating it, but most do not (for their basic line, anyway). So in the fewest words possible, here's a breakdown of the various TYPES of whey and other proteins available to you: TYPES OF PROTEIN Whey Protein Concentrate: The lowest grade. Think of it like crude oil. I make this metaphor because- like crude oil- the isolates and hydrolysates are derived from WPC. They all start as concentrate. It has the lowest % of protein per gram, so it's more difficult to increase your protein ratio by supplementing WPC as compared to isolates. Whey Protein Isolate: Refined concentrate. There are varying degrees of refinement. Think of it like gas- there is a range from basic to premium. Hydrolyzed Protein: Usually from whey, this is processed to break up the protein chains (of amino acids) into shorter chains. The shorter the chain, the more readily it can be absorbed by your body, making this the ideal post-workout protein. Warning: hydrolyzed protein is notorious for its bad taste. Casein Protein: The primary protein found in milk (whey is secondary). Casein clots in the stomach meaning it is digested over a longer period of time. For this reason it is touted for its anti-catabolic effect, so it is usually recommended as part of a nighttime formula. Milk Protein Isolate: MPI is simply an isolate of milk protein, so it mirrors the ratio of casein to whey (80:20) found in milk. You will read below that membrane micellar casein is the premium type of casein, but you should know that the casein in MPI's are this type. For this reason, it's far more economical to buy MPI's than membrane micellar casein, and still get the same quality. PROTEIN TIMING CHART Whey: 30 min to 1 hour Eggs: 2-3 Hours Meat: 3-4 Hours Casein: 7+ Hours Of course there are many other kinds of protein powders: soy, milk, egg, hell, even dried concentrated cow's blood. I believe in consuming these proteins as much as possible from their whole food sources; since the recommended amount of protein coming from powders and supplements is already restricted, I use an MPI as my anytime protein. I use whey proteins PWO. This is in accordance with Berardi's Precision Nutrition system, although of his many ideas, this one is less controversial. Soy has earned a horrible reputation lately, and although I think people are becoming perhaps a bit nazistic on soy-containing products (like marinades with soy oil in them), soy proteins are the worst offenders for raising estrogen. My updated advice is to avoid them. A good rule of thumb with protein- as with all foods- is to vary your sources. It's healthier. If you'd like to read more on that, here is something of an EAS primer on proteins as well: Protein Primer by Dr. Jose Antonio of EAS I customize my protein. Two retailers: 1) Protein Factory 2) True Protein Here's a basic breakdown, in order, of better sources to lesser sources, in each category, without explanation (trust me or research...I might be wrong, after all): WHEY PROTEIN CONCENTRATE No grades. Check the label of ingredients on the protein canister you want to buy. Under whey, does it list concentrate, isolate, hydrolyzed, or a combination of all three? Which does it list first? Almost without exception you will see concentrate, if you see the others at all. So in comparing these proteins, assuming that's all that's packaged, your only criteria should be cost and taste. WHEY PROTEIN ISOLATE (Best to Worst) Cross Microfiltration Whey Isolate Ion Exchange Whey Isolate Cold Filtration Whey Isolate HYDROLYZED PROTEIN Grade is determined by lowest weight average molecular weight*. For example, Protein Factory has three grades of hydrolyzed whey: 1) Hydrolyzed 360, 2) Hydrolyzed 520, 3) Hydrolyzed 1400. The number indicates the average molecular weight of each protein molecule; the lower the number the shorter the chain, the shorter the chain the quicker your digestion, the more "anabolic" its effect. CASEIN (Best to Worst) Milk Protein Isolate Membrane Micellar Casein Calcium Casein *Not molecular weight (aka molecular mass). These are different terms in chemistry. The lowest weight average molecular weight tells you the average weight of each polymer (a molecule made up of many smaller molecules), and protein chains are just that. Molecular weight will tell you only the average weight of a molecule of a particular substance (so it tells you only about the size of a single molecule, nothing about the length of a protein chain that molecule contributes to build).