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What Is Whey Protein And How Is It Made?

Bruce Kneller

Perhaps you’re wondering a little bit about protein powders and how they are made. In this article, I’ll briefly discuss the process for producing commercial quantities of protein powders that you see for sale in brick and mortar stores as well as online. Please remember, this is a brief overview of protein powders and how they’re made and not a comprehensive “be all, end all” commentary. There will be exceptions to some of the information described below.


Essentially, protein powders are a highly processed and dehydrated form of protein that can be reconstituted (mixed) with water and other beverages to form something you can drink (e.g., a shake). They’re used for various purposes outside of bodybuilding, but within the sport, protein drinks are used primarily to help build muscle mass and to increase overall caloric intake. Generally speaking, the shake is supposed to give you all the benefits of a protein-rich food source with added convenience and portability.

The Whey Protein Institute (www.wheyoflife.org) notes that the most common forms of protein found in sports nutrition products are whey proteins and caseinates, which are all bovine sourced (derived from cow milk). In case you’re wondering what the difference is between milk and whey proteins, milk proteins generally consist of 70 to 80 percent casein and 20 to 30 percent whey protein. We’ll talk a little more about this in a moment.

In addition to milk, whey, and caseinates, you may see some protein powders that contain non-dairy forms of protein such as soy, egg, and rice proteins. These proteins absolutely do have their places as dietary supplements and as foodstuffs, but generally speaking, they’re grossly inferior to milk, whey, and casein as sources for use in bodybuilding, fitness, athletics, etc. Unless you have a reason for not wanting to use a milk-, whey-, or casein-based product (e.g., you have an allergy to milk proteins or are a vegetarian), I would avoid any and all products that contain egg-, soy-, or wheat-based proteins as they tend to be less “complete” in their amino acid profiles than dairy-derived proteins. In fact, the National Dairy Council websites (www.nationaldairycouncil.org) has a nice FAQ about whey proteins and clearly takes the position that all “…protein found in most plants, including legumes, seeds, nuts, vegetables, and grain products, are considered ’incomplete’ proteins because they lack some of the essential amino acids needed daily.” So why use them if you don’t have to?

Please note: As most people reading this are likely to be interested primarily in whey proteins, I will focus much more on this topic than caseinates.


Whey protein is a high-quality protein naturally found in milk products. It is a “complete” protein containing all of the essential amino acids required of the human body and is easy to digest. Whey protein is also one of the best sources of branched-chain amino acids (BCAAs) including leucine, which has been shown to stimulate muscle synthesis. Interestingly, even a small amount of whey protein has been shown to be very beneficial, with as little as 10 grams of whey protein (combined with carbohydrates) shown to stimulate the rebuilding of muscle when consumed immediately after exercise.

All whey protein originates at dairy farms, as it’s naturally present in cow’s milk. Two or three times per day, cows are brought into a specialized area called a milking parlor, where the milk is collected from them. The milk collected from the cows is usually transported from the dairy farm to a manufacturing and processing center. Large liquid tankers that store up to 50,000 gallons of milk are generally employed for this purpose. Upon arrival at the manufacturing and processing center, the milk is tested to ensure it is safe. Whey protein is one of two major proteins found in cow’s milk, with about 20 percent of the protein found in raw milk being whey protein. Raw milk itself is made up of hundreds of constituent parts. Some of these parts exist in suspension and some in solution. Whey protein is produced during the process of making cheese, which starts when certain enzymes are added to milk, causing it to separate out into these constituent parts. One of the parts is called curds. The curds are used to make cheese, leaving behind whey protein in the liquid portion. This liquid whey is then pasteurized and dried into a powder for various uses. Some examples of processing methods you may have heard about include microfiltration and ion exchange.

This method uses fine specialty filters to strain the protein. The filters are called micro-filters or ultra-filters because the size of the holes/pores of the filters is microscopic. This is a physical means of removing the contents from the protein.

This is another method utilized to concentrate and purify whey protein. The protein is placed into an ion exchange tower and undergoes a chemical purification process. Typically, two chemicals are used in this process: hydrochloric acid and sodium hydroxide. Ion exchange is usually less expensive than microfiltration, but it also denatures—in other words, causes damage to—some of the amino acids. Some of the affected molecules can include immunoglobulins and glycomacropeptides (which may improve calcium absorption and boost immune function). However, most of the contents are left intact, and I would speculate that this process will not affect most people who consume products containing whey protein one way or another. Once the protein has been concentrated, it is then placed into a drying tower to remove the remaining water. The final step is to package the protein powder into various-sized containers (e.g., 25, 50, or even up to 1000 kilograms) and ship them to distribution centers.

There are essentially three types of whey protein; whey protein concentrate, whey protein isolate, and hydrolyzed whey protein are the highest quality sources.

Many whey protein powder supplements that you find for sale often list whey protein concentrate on the label as the first ingredient, so let’s start with this one. The amount of protein in whey protein concentrate can vary from a low of 25 percent to a high of 89 percent. In sports nutrition, the most common type of whey protein is 80 percent protein (abbreviated WPC or WPC80). The rest of the product consists of lactose (4 to 8 percent), fat, minerals, and moisture.

Whey protein isolate (most typically abbreviated WPI or WPI90) is the “purest” form of whey protein used for commercial applications, containing 90 to 95 percent protein. It is an excellent source of protein for people who are lactose intolerant, as it contains little or no lactose. WPI is also very low in fat. The price of WPI products is usually significantly higher than WPC due to the purity and higher protein content of the product. 

Often abbreviated as WPH, this product is made when the relatively large protein polypeptides in the whey protein have been broken down into much shorter chains (e.g., di- and tripeptides). This allows the whey protein to be digested and absorbed much faster in the intestines and may reduce the potential for allergic reactions. Hydrolyzed whey protein is very expensive, has a bitter or acidic taste, and must be specially treated to allow it to be soluble/mixable in water and other beverages. This type of protein is most often found in baby formulas and specialized medical nutrition products. 

The table below is taken from information found in 21 CFR Section 184.1979, which defines the parameters for these three types of whey proteins for sale in the United States.

WPC 25%-89% 4%-52% 1%-9% Most common protein found in protein powder and protein bars; used in sports nutrition, weight gainers, etc.
WPI 90%-95% 0.5%-1.0% 0.5%-1.0% Highest percentage of protein of all commercial whey products. Note: All proteins including WPI contain some lactose/ carbohydrates, but FDA labeling laws may allow some WPI products to claim “zero carbohydrate” status.
WPH 80%-90% 0.5%-10% 0.5%-8.0% Used in infant formulas and specialized medical nutrition products; very bitter or acidic taste; fast acting and fast digesting.

All whey proteins tend to be faster digesting than milk proteins (which are generally 70 to 80 percent casein and 20 to 30 percent whey protein) and pure caseinates. This makes whey proteins ideally suited for post-workout recovery and perhaps less well suited as a pre-workout product, as a general snack, or as a “before bed” type of product.


Casein is the principal protein found in cow’s milk, from which it has been extracted commercially for close to 100 years. It is responsible for the white, opaque appearance of milk, in which it is combined with calcium and phosphorus as clusters of casein molecules called micelles. Caseins make up 80 percent of the proteins in cow milk and between 20 and 45 percent of the proteins in human milk. Casein has a wide variety of uses outside of sports nutrition: It’s a major component of cheese, it’s used as a food additive, and it’s also used as a binder for safety matches. When used in foods and protein powders, caseins supply amino acids, small amounts of carbohydrates, as well as calcium and phosphorous.

An interesting property of caseins is their ability to form gels or “clots” when exposed to acid (e.g., in your stomach), something that makes caseins very efficient in supplying amino acids. The gel is able to provide a sustained or slow release of amino acids into the plasma pool, which can last for several hours. This usually provides superior nitrogen retention and use by the body. Also, there is some evidence that caseins lead to higher IGF-1 levels in mammals than other forms of proteins. Thus, due to their slower digesting properties, casein-based products are probably better suited as in-between meal snacks and before bed to help bodybuilders keep their muscle in a prolonged anabolic state.

Caseins are produced by means of large centrifuges that produce cream (for the manufacture of butter or other milk fat products) and skim milk. Skim milk can thus be considered as the raw material from which caseins are made. The skim milk is then acidified to produce acid casein, which is then separated from the whey. It is then washed and dried. Water-soluble derivatives of acid caseins, produced by reaction with alkalis, are called caseinates. Most caseinates (we will use calcium caseinate for our example here) will contain over 90 percent protein and almost no lactose or fat. They are around 95 to 98 percent soluble in water (sodium caseinate is virtually 100 percent soluble in water) and are usually less expensive than whey proteins. Caseinates, especially calcium caseinates, tend to have a chalky appearance and taste. As they are low in lactose, caseinates are also well suited for people who are lactose intolerant.

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