What is casein? How to properly take the protein casein?

What is casein? How to properly take the protein casein?

What is casein? How to properly take the protein casein?
What is casein? How to properly take the protein casein?

What is casein?

What is casein

Casein is a complex protein that naturally exists in milk and is actually the main raw material for the production of cheese and various cheeses. Even the name casein comes from the Latin caseus-cheese. Casein protein represents about 70-90% of the spectrum of pure milk proteins, while whey protein no more than 2-5%.

Casein can be used as a sports diet for weight gain. Unlike whey protein, "fast" protein is considered to be highly digestible and is called "slow". Most recommendations suggest that casein supplements should be taken at bedtime and during chronic malnutrition.

However, the evidence base for casein is contradictory. Studies show that even the division of proteins into "fast" and "slow" is very arbitrary. In addition, compared to other types of sports nutrition, the experiment does not reveal the main advantages of casein. However, the price of casein is usually significantly higher than the price of the isolate

Casein and gluten: twin brothers

The behavior of casein in the stomach is similar to gluten, which is also a complex protein (the main difference is that gluten is a vegetable protein, while casein is an animal protein). Both form a clot, sticking to the stomach contents and slowing down digestion.

Traditionally, casein and gluten are the raw materials for making technical glue. Many nutritionists believe that gluten is the main enemy of health. It is associated with obesity, weakening of the immune system and leads to the development of inflammatory diseases in the gastrointestinal tract. Natural casein (cottage cheese, cheese) rarely causes food allergies, but processed casein used in sports nutrition is increasingly seen as a potential health hazard.

Is casein a slow protein?

Is casein a slow protein?

The general perception of the slow rate of casein absorption is based on research conducted 25 years ago. In this study, sixteen people were divided into two groups and they ate different types of milk protein on an empty stomach. The main indicator is the level of the amino acid leucine in the blood, twice an hour.

The picture on the left is the final result of the aforementioned casein study, and the picture on the right is their explanation in advertising material. For "clarity", casein ads do not use the average value, but the maximum value, which creates an inaccurate impression of huge differences. Interestingly, the study did not examine the effect of casein on weight loss or muscle growth at all.

Effect of casein on muscle growth

When whey protein is used, the level of leucine tested first increases, reaching a maximum of 30-60 minutes, then gradually decreases. In the case of casein, the level of the amino acid also initially peaked (about 60% of the maximum for whey protein), then decreased, but more gradually than in the case of whey protein - while the total amount of protein absorbed was the same.

Separately, we note that there is no scientific evidence that a slower rate of casein absorption is in any way beneficial to athletes' metabolism. Recommendations for taking casein at night, as well as all other recommendations for the use of casein protein for muscle growth or weight loss, are based solely on the recommendations of manufacturers and advertising.

Amino acids in casein protein

Another fact highlighted in the advertising of casein protein is the increased content of essential amino acids (especially  BCAA amino acids  ). Sports nutrition manufacturers then like to list the benefits of these amino acids for muscle growth - including speeding up recovery time, activating anabolic processes, and more.

In part, this statement is true - the content of important amino acids in casein is 15-30% higher than in whey protein. However, since both are made from cow's milk, the differences are far from fundamental. In addition, as Fitseven has already noted, casein protein costs at least 30% more than a regular isolate.

How to take casein properly?

The mechanics of the aforementioned scientific study of casein protein intake are also far from real life. Subjects did not eat anything 10 hours before the start of the study and 7 hours after taking casein or whey protein. In fact, it is completely incomprehensible how the real conditions (ie the presence of such in the food in the stomach) will affect the final rate of casein absorption.

It is likely that the presence of fat or complex carbohydrates (especially starch and  fiber  ) in the stomach will slow down the absorption of ordinary whey protein, which makes it look like casein. In other words, casein protein does not have a scientifically recommended dosing regimen, and advice on taking it at bedtime is based solely on the manufacturer's opinion and not on scientific evidence.

Casein Protein Potential Harm

In addition to studies that have failed to demonstrate that casein has any significant benefits over whey protein, there are some preliminary studies that show a link between processed casein consumption and cancer. It has also been found that, like gluten and lactose, some people may be allergic to casein.

Once again, we noticed individually that although it is easy to produce (remember that milk protein is 80% casein), its price as a form of sports nutrition is higher than that of high-quality whey isolate (given this point) Only 2% -5% of the milk protein content). However, if you are still unsure about the need and importance of casein intake, remember that casein is already included in cheese and cheese.


Called "slow-release protein" in sports nutrition ads, casein has been known for hundreds of years as a raw material for cheese and cottage cheese. There is no scientific evidence of its benefits for muscle gain or weight loss, but there are studies that suggest the potential harm of processed casein protein, which is essentially the twin brother of gluten.

Scientific sources:

  1. Nutritional evaluation of caseins and whey proteins and their hydrolysates,  source
  2. Slow and fast dietary proteins differently modulate postprandial protein growth,  source