Whey Concentrate vs. Isolate vs. Casein: What’s The Difference?


Protein powders are among the most popular fitness supplements today.

Thanks to their affordability and versatility, countless people today swear by protein powders as a means of elevating their health and fitness.

But there is a problem:

With the number of available options, it can be challenging to choose. Whey alone comes in different forms, and this doesn’t even account for casein and the many non-dairy options.

To make it easier for you, we’ve put together this post. In it, we’ll take a brief look at some of the most common protein powders and what makes them unique. Let’s go.


Whey Concentrate vs. Isolate vs. Casein: What’s The Difference?


Whey is a type of protein found in dairy. Specifically, this is the liquid part that separates during cheese production. Back in the day, people would throw it out or feed it to livestock because they didn’t know of its commercial value. Today, whey is one of the most widely consumed proteins on the market.

The two most popular forms of whey are concentrate and isolate. Once collected, whey protein undergoes processes to boost its protein content. The protein is then dried and consists of around 80 percent protein (1). A 100 grams of whey concentrate offer around 80 grams of protein.

Whey isolate goes through similar processes, but the goal is to further reduce carb and fat content and result in 90 percent protein or more (1). So, 100 grams of whey isolate typically offers 90 or more grams of protein.

Now, it’s worth noting that both types of protein have similar amino acid profiles because they are derived from the same source - whey.

Casein is also a protein found in dairy. The primary difference is that casein tends to digest more slowly, allowing for a steadier release of amino acids into the bloodstream (2). When casein enters the stomach, it forms into a gel, which prevents stomach acid from breaking it up quickly. 

In contrast, whey typically digests more rapidly, releases many amino acids, and levels go back to normal more quickly (2).

There is also a hydrolysate form of casein that is said to digests more quickly, but research doesn’t find this to be the case (3).

All three types of protein deliver similar outcomes. Whey and casein are complete proteins and behave similarly in the body. The primary difference between them is the rate of digestion. Since casein digests more slowly, it helps maintain higher levels of amino acids in the blood for longer, which can prevent muscle protein breakdown, and aid with recovery and growth.

Still, research is developing, and it seems that the total daily protein dose is the most important factor (4).


But What About Bio-Availability And Digestibility?


Bio-availability is a measure of how well the body can absorb and use the nutrients of a given food or supplement (5). Digestibility measures how much nutrition a food offers in a given amount. According to researchers (6): 

“..protein digestibility is an important factor to estimate the protein availability for intestinal absorption after digestion reflecting on the efficiency of protein utilization on diet.” 

For instance, cooked egg protein has a bio-availability score of roughly 90 percent (7). Whey and casein also score highly on the scale, and it seems that whey isolate has the highest rating of all.

The question is, would they make a significant difference in the grand scheme of things? We don’t know so far. It might, and it might not. The best thing you can do for the moment is making sure to get enough protein each day (around 0.8 grams per pound of body weight) from mixed sources (8).