Whey Protein is a substance made from Whey. Whey Protein contains the Proteins from Whey.
Uses of Whey Protein
Whey Protein (or more specifically, flavored Whey Protein) is used by many people who exercise to help with muscle growth and to help keep existing muscle.
Note, Whey Protein by its self will NOT result in muscle growth!
One needs to regularly perform certain kinds of exercises while regularly consuming Whey Protein, to gain muscle growth. (I generally consume about 3 or 4 heaping table spoons of flavored Whey Protein, mixed into Milk or Water, after exercising. And sometimes consume it as a snack.)
Essentially, Whey Protein provides the body with an abundance of certain kinds of Proteins... the point of doing this is because people often do not get enough of these Proteins from the Food they eat... and thus, even if they regularly exercise, if they do not have those Proteins available to create muscle, they will NOT create the muscle.
How Whey Protein is Made
As I have been told... to make Whey Protein, one starts with Milk. (I imagine that this would probably be Cow Milk, since that is the most common form of Milk in use today, in the area where I live.)
The Milk is then turned into Curds and Whey.
The Whey is then separated from the Curds. (Because it is the Whey that we want from this. The Curds are NOT used for this. You can go make Cheese or something with them if you do not want to waste the Curds.)
This Whey that has been separated from the Curds is a liquid. This liquid is then dried to make Whey Powder. (Based on some things I have read, I believe it is important NOT to over heat the Whey to make Whey Powder, because this heating will change the structure of the Proteins. This changing is called denaturing or unfolding of the Proteins. And it is believed by some that denatured whey protein does NOT have the same properties as non-denatured whey protein... and thus denatured whey protein will NOT aid in muscle growth and maintenance.)
The Whey Protein is then separated from the Whey Powder through a process called Microfiltering... which uses Static Electricity to separate out the Proteins... which is what we want and what makes Whey Protein.
This Whey Protein is then usually flavored because pure Whey Protein tastes horrible.
Flavored Whey Protein
Whey Protein by itself tastes horrible. And I do not know of anyone who cosumes Whey Protein without flavoring of some kind. (At least, not on purpose. Sometimes containers with flavored Whey Protein will contain small amounts on non-flavored Whey Protein.)
Common flavorings of Whey Protein include: Chocolate, Vanilla, and Strawberry. Other flavors exist, but, to me, these seem to be the most popular.
Consuming Whey Protein
Flavored Whey Protein is usually consumed by turning it into a drink by mixing it with Milk or Water.
For those who exercise regularly, it is generally consumed after the workout -- after one finishes exercising... since it is believed that that is when the body will use the Proteins from the Whey Protein to build muscles. It is also believed that that is when the body will keep in most of the Proteins from the flavored whey protein drink, instead of just crapping or pissing it out without even using it (and essentially wasting it).
What Whey Protein is Made Up Of
As I have read, Whey Protein is primarily made up of: beta-lactoglobulins (BLG), alpha-lactalbumins, bovine serum albumin (BSA) and immunoglobulins (Ig). (Although there are other things in it, including other Proteins.)