The term “casein” refers to a type of protein found in regular milk, which is rich in calcium, digests slowly, and has anti-catabolic effects. It is extremely popular in bodybuilding for muscle mass gain, as well as among those losing weight for fat loss.
In this article, we will discuss the special benefits of casein protein for muscle growth and weight loss, the products in which it is found, how to properly take casein, and its potential harm to health.
Main thoughts:
Casein protein is derived from milk. It is a “slow” protein with a complete amino acid profile
What is casein and how does it differ from protein?
Milk protein consists of two types of protein – casein (80%) and whey protein (20%).
Casein is classified as a “slow” protein because it digests and absorbs over several hours, compared to whey protein, which has an absorption time of about 30 minutes.
This is one of the most important differences between them, explaining the benefits of casein in bodybuilding (see below).
Like other animal proteins, casein is a complete protein, meaning it contains all the amino acids necessary for the body in optimal ratios 1.
It also contains many other biologically active compounds that are important for health and immunity in particular 2,3.
– How does casein differ from protein?
It doesn’t. It is indeed the protein that is part of milk protein and is digested slowly.
Casein protein is obtained from milk. It is a “slow” protein with a complete amino acid profile.
Types of Casein
Casein can be conditionally divided into two groups:
- casein from whole dairy products;
- sports or industrial casein.
Sports casein is available in two main forms:
- micellar casein – most commonly used in protein sports nutrition;
- casein hydrolysate – protein molecules are broken down into parts, which speeds up digestion and absorption compared to micellar casein; due to its rapid absorption, it is sometimes used as an alternative to whey protein.
Both micellar casein and casein hydrolysate are derived from milk protein.
Both types have a very high protein concentration, but there are significant differences between them.
Micellar Casein
Micellar casein is considered the best type of sports casein. It is obtained through cold filtration, which keeps the protein molecules intact and prevents contamination with chemicals.
This is important, as this whole protein digests slowly, providing the benefits of slow proteins for muscle growth, while also retaining beneficial properties for health.
Additionally, according to doctors’ reviews on the benefits of whole protein compared to free amino acids, the digestion of whole foods is accompanied by the release of a whole range of substances (enzymes and hormones, including growth hormone), which are important for health and muscle mass gain.
Casein Hydrolysate
Casein hydrolysate consists of casein molecules that have been broken down into parts, making it a “fast” protein: it digests as quickly as whey.
That is, in fact, this casein loses its advantage as a “slow” protein, which is why it is so beneficial for muscle mass gain.
But what is even worse is that it acquires a number of significant drawbacks.
In the production of hydrolysate, acids and thermal heating are used, which not only reduces its taste qualities (casein acquires a bitter aftertaste) but also significantly lowers the quality of the protein: a large percentage is damaged and becomes non-functional 19.
This protein becomes not only useless but can also increase the risk of cancer (see our material about the harm of sports casein).
Additionally, hydrolyzed casein is more expensive than micellar casein due to additional technological costs.
Micellar casein is the best type of sports casein; hydrolysate loses the properties of slow protein, has worse taste qualities, and is also more expensive.
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What products contain casein protein?
Sources of casein protein are dairy products and all derivatives from them.
In different types of dairy products, the ratio between whey protein and casein slightly varies. To estimate the quantitative content of casein in them, you need to multiply the amount of protein by 0.8 (80%).
For example.
– How much casein is in cottage cheese?
In 100 grams of cottage cheese, there are 16 grams of protein, so the share of casein is approximately 16 g * 0.8 = 13 g.
For comparison, a 33-gram serving of sports casein contains about 24 grams of protein (casein), 3 grams of carbohydrates, and 1 gram of fat.
| Casein content in products (per 100 g) | ||
|---|---|---|
| Product | Protein | Casein |
| Cottage cheese | 16 | 13 |
| Greek yogurt | 7 | 5.6 |
| Milk | 3.4 | 2.7 |
| Cheese | 24 | 24 |
| Sports casein | 72 | 72 |
A good source of casein protein is cottage cheese and cheese. All the protein in its composition is almost exclusively casein, as whey protein is separated during its production.
In cottage cheese, the relative share of whey protein is higher than in cheese, but its advantage is in significantly lower fat content.
Less obvious sources of casein protein can be other products that contain milk or its derivatives. For example, ice cream, baked goods, pizza, baby food. The quantitative content of casein in them is small.
The sources of casein protein are dairy products (milk, cottage cheese, cheese); it is also found in small amounts in other food products made using milk.
What is the purpose of casein in bodybuilding? Useful properties
In bodybuilding and other strength sports, casein has been used as sports nutrition for decades.
It all started with dairy products that were consumed in liters and kilograms, and then gradually sports casein appeared on the scene in powder form.
Today, casein is better known as a type of sports nutrition. It is one of the most popular types of protein. It is available in two main forms: the aforementioned micellar casein and hydrolysate.
– Which is better, sports casein or casein from natural products?
This is a controversial question, as is the more general one: “which is better: sports protein or natural protein products?“.
The answer to it largely depends on whom you ask.
Manufacturers and sellers of sports nutrition will undoubtedly try to convince you that without their products “it is impossible to gain muscle mass“.
Independent scientists and doctors will respond that “mass can be gained by eating exclusively natural products” (as bodybuilders did during the golden era of bodybuilding), and will also point to numerous facts about the harm of sports (technical) casein.
Want an example?
In the article What is better, soy or whey protein?, we discussed how the popular portal bodybuilding.com, describing the advantages of soy protein (obviously to stimulate its sales), relies on arguments from “scientists” who are clearly lacking objectivity and are collaborating with one of the soy protein manufacturers.
And here is a comparison of absolutely contradictory viewpoints from popular internet resources (represented by the well-known “guru” of sports nutrition Jimma Stoppani, who also writes for bodybuilding.com) and scientists regarding the benefits and effectiveness of another sports supplement – arginine.
Scientists warn that among sports caseins, there are many low-quality products, the protein of which is not only non-functional (useless for muscle growth) but can also increase the risk of cancer. Read our article about the harm of sports casein.
High-quality casein has amazing properties that explain its benefits.
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1 The benefits of casein for muscle mass gain
The effectiveness of any type of protein for muscle growth is determined by: the completeness of the amino acid profile and how well it is absorbed.
Casein has both.
Firstly, it has an ideal amino acid profile, which includes all essential and non-essential amino acids, including the most important for muscle growth – leucine, one of the three BCAAs 8-10.
Secondly, the benefits of casein are explained by its slow digestion and absorption time. This means that after consumption, it provides nutrition for muscle cells over an extended period.
In contrast, whey protein, as is known, is digested very quickly, causing a spike in amino acid concentration in the blood.
This is very good at times of high nutrient demand for muscle cells: immediately after or during prolonged training.
At the same time, if fast whey protein is consumed when the demand for amino acids is low, the sharp increase in their concentration in the blood can have the opposite effect: they do not have time to be “absorbed” by the muscles, and some of them are converted into fat or energy.
From the perspective of muscle growth and maintaining muscle definition, this is not very good.
Thanks to the slow gradual absorption, casein protein is beneficial for muscle synthesis (the creation of muscle cells and the recovery of existing ones) at times when the risk of catabolism is high, for example, at night during sleep 4,5 or when there is no opportunity to eat regularly. For this reason, it is called “anti-catabolic protein” 6.
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See how this is confirmed by scientific research.
Scientific research on the benefits of casein for muscle mass gain
In one of the experiments, scientists gave one group of subjects casein protein, another group whey protein, and then over the course of 7 hours checked the amino acid composition in the blood, particularly leucine – one of the most anabolic amino acids included in BCAA 7.
What they found:
- after consuming whey protein, there was a rapid spike in amino acid concentration in the blood, which also quickly decreased; whereas in the case of casein, there was no pronounced peak, but elevated amino acid levels were observed for a significantly longer time;
- in the case of casein, significantly fewer amino acids were “burned” as fuel for energy, meaning more remained available for muscle function 8.
For these reasons, casein protein is very often recommended to be taken before sleep to prevent muscle catabolism during the “forced” fasting period at night.
In another study, it was demonstrated that taking casein before sleep by young athletes led to an increase in muscle fiber size by 8.4 cm2 in cross-section, compared to 4.8 cm2 in those who took a “dummy” (placebo) 12. Also, in the casein group, muscle strength increased by 20% more.
The benefits of casein for muscle mass gain are explained by its slow absorption rate: it better protects muscle cells from catabolism and creates better conditions for muscle growth during periods of forced fasting (for example, at night).
2 The Benefits of Casein for Weight Loss
It is scientifically proven – protein is beneficial for weight loss. The same applies to the type of protein – casein.
In short, this is explained by the fact that protein provides better satiety, reducing feelings of hunger, and also requires more energy for its digestion.
It is important to understand that when we talk about the benefits of casein for weight loss, we do NOT mean specifically casein and even more so – specifically sports casein. No. We are talking about any protein.
More information about the benefits of protein for weight loss can be found in the link above, and here we will only present the results of one scientific experiment.
In this study, the effectiveness of a low-calorie diet for weight loss was tested on three groups of classic overweight police officers 11.
In the experiment:
- one group of subjects took casein protein (1.5 g per kg of body weight) + was on a low-calorie diet (80% of the required daily caloric intake) + engaged in strength training;
- another group took whey protein and was also on a low-calorie diet and trained;
- the third group was only switched to a low-carbohydrate diet.
The experiment lasted 12 weeks.
As a result, the researchers found that those who consumed casein gained twice as much muscle mass as those who consumed whey protein, lost ~3 kg more than those who consumed whey protein and 5 kg more than those who simply restricted calories.
The body fat percentage decreased twice as much in the casein group compared to the whey protein group.
Scientific studies confirm the benefits of casein protein for weight loss, but this is not solely due to casein itself and certainly not to the corresponding sports nutrition: any protein is beneficial for weight loss, especially whole (NON-hydrolyzed).
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3 Other health benefits of casein
A number of scientific studies confirm that the consumption of casein has several important health benefits:
- benefits for the immune system: studies indicate that casein has antibacterial effects, improving immune system function 13;
- control of triglyceride (fat) levels in the blood: in one experiment, the level of triglycerides fell by 22% when consuming casein 14;
- reduction of free radicals: the biologically active components of casein have antioxidant effects, preventing the formation of dangerous free radicals, which are one of the factors in cancer development 15.
Harm of casein
The question of the harm of casein is somewhat analogous to the question of whether protein is harmful.
Scientific studies indicate the relative safety of casein and other proteins in moderate doses.
Consuming protein in large doses is dangerous for health. This is especially true for those individuals whose kidney or liver function is already impaired 16-18, but is not limited to them.
Excessive protein consumption alters the acid-base balance in the body towards acidosis, which stimulates the leaching of calcium from bones, the formation of kidney stones, and creates conditions for the growth and development of cancerous tumors.
Animal proteins with high biological value pose particular danger from this perspective – the most popular in bodybuilding.
One reason is the high content of the amino acid methionine, which is also popular in bodybuilding as a separate supplement.
Sometimes such a recommendation is given: “If you take 1-2 doses of protein/casein per day, the likelihood of any side effects is low“.
But any such precise dosage guidelines do not hold up to scrutiny: what if two casein shakes are consumed along with 2 kg of meat, the same amount of cottage cheese, and fish?
The total amount of protein in the diet matters.
It is important to remember that even the most beneficial substance or product can turn into a poison in excessive amounts.
And for athletes, it is characteristic to consume a huge amount of protein and amino acids both from sports nutrition and natural products.
It is also worth mentioning that scientists warn about the low quality of most sports caseins, as the technological processing with heat and acid damages the protein molecules.
Therefore, it makes sense to prefer natural products containing casein protein or milk protein and its concentrate, which are made without harsh technological processing.
Finally, a quote from one of the researchers on the benefits and harms of casein and other dairy products regarding the harm of sports casein (the full material is here):
”The protein casein from whole milk is the most functional, as its protein molecules are gathered in clusters that include calcium, phosphate, and citrate ions, and it complements the body’s acidic composition without leading to excessive oxidation.
This cannot be said about most other types of casein, which have very strong oxidative properties” 20.
Casein, like other types of protein, does not pose a health risk when consumed in moderate doses, but it can cause allergies and digestive issues in the case of lactose intolerance. Excessive consumption of casein, like other animal proteins, can be very dangerous to health.
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Allergy to casein and lactose intolerance
There are some side effects that are specific only to casein.
A fairly common problem is allergy to casein and lactose intolerance, which will prevent you from enjoying the benefits of this supplement.
There is nothing terrible about this, as there are many other non-dairy types of protein (egg, soy, combinations of plant-based proteins), which are no less (or slightly less) effective for gaining muscle mass and losing weight.
The process of technological processing of milk protein usually removes lactose (in hydrolysates and isolates, it is less than in concentrates), but trace concentrations may remain. Lactose intolerance in casein can lead to bloating and other unpleasant digestive issues.
Casein allergy manifests with symptoms characteristic of other types of allergies: swelling of the lips, mouth, face, throat (which can make breathing difficult), skin redness and rashes, runny nose, tearing, sneezing, etc.
Allergy can manifest within minutes after ingestion and requires prompt medical attention.
How to take casein for weight loss and muscle gain
The general rule for protein intake for muscle gain is as follows: fast types immediately after training, during, or before, slow types – before sleep or when there is no opportunity to eat frequently.
See in detail How to take protein for muscle growth?.
Casein protein is most often recommended to be taken before sleep, 1-2 scoops (25-50 g).
If you are using sports casein, you can simply prepare a shake in a shaker with water. Alternatively, for variety, blend it with a mixer and place it in the freezer: in 5-10 minutes, you will have protein ice cream (especially delicious with chocolate or vanilla flavor powder).
When losing weight, it is important to increase the total amount of protein throughout the day; the exact timing of intake is not particularly significant. Nor is the type of protein: whether it is casein, eggs, or cottage cheese.
By the way, some recent studies suggest that the exact timing of protein intake in bodybuilding for muscle mass gain is not of great importance 21.
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– What is better at night: cottage cheese or casein?
There is no difference, except for the volume of the portion of cottage cheese and powder that needs to be consumed to obtain the same dose of protein.
Always remember that there is no magic in sports proteins and casein in particular: you can gain muscle mass by eating exclusively natural protein products. The only significant advantage of sports proteins is that they are simply more convenient to use.
– Which is better, casein or whey protein?
Both are good, but at their own time. Both proteins are high quality in terms of amino acid profile and are very well absorbed.
The difference in the speed of digestion and absorption. Whey protein is a “fast” protein, and it is ideal to take it right after a workout when the muscles are “starving” and need building material for “repair” and recovery. The advantages of the “slow” properties of casein were mentioned a bit earlier.
For gaining muscle mass, it is better to take casein before bed or when you have to skip a full meal. For weight loss, casein can be taken at any time: what matters is not the exact timing, but the overall protein content in the diet.
We recommend: How to properly take protein for muscle growth
Conclusion
Casein protein is a type of complete protein, the benefit of which for muscle growth lies in its slow digestion rate, providing a steady supply of building material (amino acids) to the muscles over a long period.
Casein is also beneficial for weight loss. However, it is important to remember that this is a general property characteristic of any protein, not just casein.
Casein protein does not pose serious harm to health when the total protein dosage is adhered to throughout the day, but it can cause allergies or digestive issues in people with lactose intolerance.
If your goal is to gain muscle mass, make it a rule to take 1-2 scoops of casein or 250 grams of cottage cheese before bed.
If you aim to lose weight, simply increase the amount of protein in your diet throughout the day and reduce the unnecessary, yet beloved empty carbohydrates (buns, cookies, and candies).
