Casein Protein Benefits and Side Effects

Casein protein is the purest form of animal protein, and it has been used as a source of food for over 8,000 years. This type of milk-derived supplement can be found in many popular products like cereal bars, shakes, or vegan cheeses. The benefits include promoting muscle growth and aiding digestion by breaking down proteins before entering the bloodstream.


Whey protein is the most common dairy protein powder globally, and it’s popular among athletes and people wanting to lose or gain weight. For decades, whey protein has been the go-to muscle-building supplement, but casein protein is a beneficial dairy protein supplement.

Casein protein, sometimes known as “the other protein powder,” is one of the best sources of long-lasting amino acids. It delivers easy-to-digest protein in a similar way to whey.

What distinguishes casein protein from whey, pea protein powder, and even complete eggs and chicken breast meals? The timing of how casein is absorbed and how long it stays in the body are two of its biggest benefits. It is advantageous for growing muscle quickly while still keeping the body’s lean muscle tissue due to both of these aspects.

The kind of protein matters when it comes to nutritional timing.

What are some of the advantages of casein protein? First, it immediately enters your circulation, and its amino acids remain where they need to be in order to help grow muscle tissue for many hours, rather than being flushed from the body.

So, who isn’t interested in increasing lean muscle mass, curbing appetite, and reaping even more advantages from their workout (and who isn’t)? Then you should probably start utilizing casein protein. Or is it preferable to consume this protein in its natural state rather than in the shape of a problematic protein powder? Answers are on their way.

Casein Protein and How It Works

Casein protein, like whey protein, is derived from milk and is a naturally more plentiful source of branched-chain amino acids. Casein makes up around 80% of the protein in cow’s milk, which is why it’s frequently simply referred to as “milk protein.”

Casein is the “curd” in milk that can produce gels. Human breast milk contains 20% to 40% of this substance. Raw sheep cheese, a pure source of casein, is likewise high in it.

Like whey and other protein sources, casein is made up of necessary and non-essential amino acids, which serve as “building blocks.” Because the human body can generate certain amino acids on its own (non-essential) but not others (essential), essential amino acids are required to obtain via the meals you consume.

Animal meals — and even handy protein powders — are one method individuals make sure they meet their protein bases since plant foods don’t always compliment the necessary amino acids we need.

What is a casein protein powder, and how does it work? It’s a powder made in a lab by dehydrating milk components.

The difficulty is that many of the forms are denatured and isolated, leading to health problems. If possible, look for casein protein made from A2 beta-casein rather than A1 casein.

It’s normally available at most health food shops, and there are several tastes to choose from. You’ll undoubtedly note that there are around five different whey protein powders available for every brand of casein protein powder.

Whey Protein vs. Casein Protein

When it comes to muscle rehabilitation, regeneration, and development, protein is a critical component for athletes and everyone who is physically active. While most individuals in industrialized countries don’t have a protein deficit, bear in mind that protein needs rise as you get more active. They’re particularly high if you lift weights or engage in other forms of long-term training.

While you may believe that protein powders are just for serious lifters, hefty guys, or professional athletes, practically everyone may benefit from supplementing their exercises with the appropriate balance of nutrients, and protein powders simply make this simpler.

Which protein is superior, casein or whey?

  • Whey protein and casein protein have different bioavailability and muscle-building effects. Casein is a kind of milk protein that takes a long time to digest. Although whey protein has many of the same advantages as casein, it is thought to generate a faster “amino acid surge.”
  • Whey is a rapid protein source compared to casein, which means it produces amino acids immediately after consumption – but they also leave the body faster than casein. When the body receives more protein than it can utilize at one time, part of it may be flushed out via urine, oxidized, or otherwise squandered. However, this isn’t necessarily a negative thing; all forms of proteins have advantages and disadvantages, so don’t dismiss whey protein just yet. There are advantages to ingesting both quicker and slower-releasing proteins; it depends on your objectives and timetable.
  • Various amino acids are branched together at the molecular level inside a protein source like casein. Casein protein contains a smaller amount of branched-chain amino acids than whey protein, which is one of the reasons it digests more slowly and lasts longer. Casein is thought to stimulate protein synthesis slightly less than whey due to its use and timing. On the bright side, it helps prevent the body from breaking down amino acids already stored in the muscles. Intestinal motility has also been demonstrated to be slowed by casein.
  • Whey protein has a higher sulfur content than casein, affecting how the body utilizes it.
  • In principle, the two should impact body composition differently, but this hasn’t been shown in every research. Short-term consumption of both whey and casein after exercise, for example, resulted in identical improvements in muscle protein net balance, according to researchers from the University of Texas Medical Branch’s Metabolism Unit. Despite distinct patterns of blood amino acid reactions, they did not result in changes in muscle protein synthesis.

If all of this chemistry sounds a little perplexing, consider the following casein vs. whey comparison: Both casein and whey protein may be used to complement your workouts and provide all of the necessary amino acids you need, but whey has more branched-chain amino acids and, as a result, may be somewhat more effective in promoting muscle protein synthesis.

The good news is that when researchers from the University of South Florida’s Exercise and Performance Nutrition Laboratory compared the effects of both proteins on body composition and performance in female athletes, they discovered that whey and casein had identical favorable impacts. In addition, both supplements were shown to provide advantages for females, including improving performance indicators following resistance exercise and reducing body fat composition.


Health Advantages

When taken at the correct time, high-quality casein protein may provide a variety of health advantages. Let’s take a closer look at some of its most important features and applications:

1. Assists in the development of muscle mass

Casein aids in developing new muscle tissue and the increase of lean muscle mass. It is often referred to as an “anti-catabolic” protein.

So, what does this imply? First, to acquire the amino acids that are held within muscle protein, your body catabolizes or simply rips down muscle tissue. Then, it utilizes the amino acids stored for energy and aid in numerous processes, including growth and development.

The more you exercise, the more your body will look for protein to keep it running smoothly.

Is it true that casein causes weight gain? Anti-catabolic supplements include amino acids that assist limit the breakdown of muscle, saving your hard-earned muscle mass, and resulting in a healthier body composition.

2. Keeps you fuller for longer than other protein sources

Despite its fast absorption, casein is classified as a “slow-digesting” protein due to the length of time in which its amino acids remain in circulation. Protein meals, like slower-releasing carbs, may occasionally operate in the same way fast-acting carbohydrates can quickly elevate blood sugar.

Because casein protein is slowly digested, muscle tissues have a longer window of opportunity to utilize amino acids for repair and development. The timing of casein has its benefits, as you’ll see below, but depending on your objectives, there are occasions when you want to forgo it and utilize a faster-acting protein instead.

3. Makes an Excellent Meal Substitute or Pre-Bedtime Snack

Did you know that one of the essential periods for gaining muscle mass and reaping the benefits of your hard work and exercise throughout the day is when you sleep? This is because your body attempts to mend regions that have been too stressed throughout the day while you sleep.

Using casein protein to give your muscles an additional boost is one approach to take advantage of this biological process.

Casein protein is thought to last up to seven hours in circulation, which is why bodybuilders like to eat it immediately before bed. As a result, casein protein has a reputation in the fitness scene as an “excellent bedtime snack.”

A research done by NUTRIM School for Nutrition’s Department of Human Movement Sciences discovered that casein protein consumed just before bedtime is efficiently digested and absorbed, aiding muscle protein synthesis and boosting “whole-body protein balance” after exercise. In addition, amino acids function to rebuild muscle fibers during the night while someone is asleep.

Casein is a fantastic shake/snack to consume between meals if you’ve gone many hours or more without eating.

4. Can Help You Lose Weight and Curb Your Appetite

Even if you merely exercise in a “moderate” manner and aren’t trying to gain muscle mass, protein supplements may help you control your appetite and cravings. Many individuals choose protein powders because of their convenience and the fact that they may help reduce hunger to some degree.

Have you ever noticed how quickly you seek anything else to eat after eating a carb- or sugar-heavy breakfast but skipping protein? Protein is incredibly filling, and it may help you go from one meal to the next without feeling hungry or needing sweets.

Most individuals who consume a protein source with every meal (and even snacks) find that they can better control their appetite and food choices. While the results vary by individual, some individuals find that mixing protein powders in smoothies with other nutrient-dense ingredients works well as a simple breakfast, a high-protein snack, or even a meal replacement.

How effective is casein protein in controlling hunger? According to a research published in the British Journal of Nutrition, both operate similarly.

In 24 overweight adult men and women, researchers examined the hunger-reducing benefits of hydrolyzed casein protein, intact casein, and intact whey protein. They intended to see how these various protein supplements affected total energy expenditure (EE) and appetite management, or how much “calories in vs. calories out.”

Over 24 hours, both forms of casein and one type of whey protein had equal impacts on EE and hunger. At the same time, certain data revealed that whey protein worked somewhat better when it came to improving the individuals’ resting metabolic rates favorably.

How to Make Use of

When is the best time to ingest casein protein? Casein protein has long been advised as a meal replacement/snack between spaced-out meals (if your objective is to develop muscle and maybe gain weight).

Remember that casein is slowly digested, so it may take longer for it to reach your muscles after an exercise than other forms of protein (such as whey).

However, data from a 2018 research comparing the effects of casein supplementation (54 grams) in the morning vs. the evening (90 minutes or less before sleep) on measures of body composition and exercise performance in trained men and women indicated that time might not be as important. There were no significant alterations in body composition when the individuals did not modify their training program. The addition of 54 grams of casein protein in the morning or evening had no significant impact on body composition when they did not change their training regimen.

While some other studies have found evidence that taking casein before bed can help untrained individuals who begin strength training increase their metabolic rate and strength, it’s now widely accepted that you should concentrate on “the strategy of achieving specific daily protein levels versus specific timing of protein ingestion for increasing muscle mass and performance.” In other words, it’s more important to have enough protein throughout the day than it is to get it at the right time.

Because you want to provide nutrition to your injured muscle tissue as soon as possible after exercise, choosing casein over faster-acting protein sources won’t provide you with the advantages of an instant surge of amino acids. Whey protein is the superior option after a workout since it is readily absorbed and digested.

After you exercise, your muscles are looking for a quick supply of nutrients to carry out muscle synthesis, therefore avoid casein to help speed up this process.

Nutritional Information

Are you unsure how much casein protein to utilize at a certain moment or how much protein you need in general? Protein requirements vary from person to person and are influenced by a variety of circumstances; however, the following are some basic suggestions for utilizing casein protein:

  • If you’re an athlete or a really active individual, you’ll need roughly 0.68–1 gram of protein per pound of body weight.
  • If you want to reduce weight and tone up, aim for 0.45–0.68 grams per pound of body weight.
  • To keep your health and weight in check, aim for 0.36 grams per pound of body weight.

The calories and protein content of casein protein powder vary depending on the brand. Look for a brand that’s low in sugar or sweetened naturally with organic stevia extract and natural sweeteners like cocoa powder or vanilla extract to get the maximum advantages.

A serving of casein powder contains approximately:

  • Calorie Count: 120
  • Protein content: 23 g
  • Fat: 1 gram
  • Sugar: 1 gram
  • Calcium: 450 milligrams (45 percent)

To put this in perspective, a 140-pound woman who is active and wants to improve her diet may aim for 63–95 grams of protein per day, which means a serving of casein protein might cover one of her three major meals.


Casein A1 vs. Casein A2

Milk is mostly made up of water, with a small percentage of sugar (lactose), protein, fat, and minerals. There are many different types of protein molecules in milk.

A2 beta-casein is the kind that animals have been producing naturally for thousands of years, even before being domesticated around 10,000 years ago. It’s thought to be simpler to digest, and studies show it has fewer negative health impacts than the other form, A1 casein.

A1 is a “newer form of casein” that emerged after the domestication of animals a few thousand years ago. It developed when some genes drove proteins to alter, converting proline amino acids to histidine.

A1 beta-casein is becoming increasingly common in dairy cows, which provide most milk in the United States and even Europe.

Each cow has an A1/A1 or A2/A2 genotype, which influences the milk it produces. Therefore, milk products are preferred, including all dairy meals and whey/casein protein supplements derived from cows (or goats) with a high A2 casein content.

When A1 beta-casein triggered a transition from proline to histidine amino acids, people had difficulty digesting and metabolizing milk effectively. In reality, most persons who are intolerant to cow milk are sensitive to A1 casein, one of the proteins contained in it. They can’t digest A1 since they don’t have the necessary enzymes.

This sensitivity has now been related to a number of ailments, including autoimmune responses, food allergies, digestive problems, type 1 diabetes, heart disease, and more. Although A1 is known to cause inflammation, milk with largely or entirely A2 casein has significantly less (or none) inflammatory effects.

How can you tell if the casein or whey protein you’re eating is from A1 or A2 cows? A2 milk is considered to be produced by a wide range of mixed-breed dairy cow herds, including Jersey, Guernsey, Brown Swiss, milking shorthorn, Friesian, and others.

Purchasing goods manufactured from these breeds (preferably organic and grass-fed varieties) should result in reduced levels of A1 beta-casein. In addition, some protein supplements combine both dairy and non-dairy proteins into a single product.

Side Effects and Risks

You’re probably aware that casein protein is derived from milk, most likely cow’s milk. Lactose intolerance is most often caused by homogenized and pasteurized cow’s milk, which is also a frequent allergy.

More than 20 allergens (including A1 casein) are found in cow’s milk, which may induce allergic responses or digestive issues.

What are some symptoms of a dairy allergy, casein intolerance, or casein allergy? Among the signs and symptoms are:

  • Stomach bloating, diarrhea, or abdominal cramps
  • Rash
  • Hives
  • Swelling, particularly of the lips and face
  • Wheezing
  • throat constriction
  • Having difficulty swallowing

If you’ve had difficulties digesting milk-derivative goods in the past due to lactose intolerance symptoms, consider raw milk, goat’s milk, or organic A2 milk. One approach for avoiding casein protein side effects is to obtain casein protein manufactured from goat milk, which contains just A2 casein naturally.

Goat milk is said to be equivalent to human breast milk, causing fewer digestive problems and allergic responses than cow milk. A2 casein protein products derived from cows that don’t generate A1 casein, such as Jersey and Guernsey cows, are also available.

You should do your homework since most bovines in the United States, Western Europe, and Australia are Holstein and Fresian cows, which generate A1 casein.


  • What exactly is casein? Casein protein is a naturally abundant source of branched-chain amino acids produced from milk.
  • Casein protein provides many of the same advantages as whey protein, so it’s your best bet if you’re searching for a protein source other than whey.
  • Casein is a slower-acting protein than whey, taking longer to reach the muscles and exit the body. As a result, whey protein may be a better choice if you want to gain muscle mass rapidly.
  • Because of its slow-acting impact, casein works particularly effectively when you’re sleeping, helping your body repair and even develop muscles. However, opt for A2 casein from organic and grass-fed cows or goats when purchasing and consuming casein. It might be difficult to tell the difference between A1 and A2 casein, so go for the most natural sources. A2 casein is the healthier, more natural type that has been generated long before animal domestication.

Frequently Asked Questions

What is casein protein used for?

A: Casein protein is the main type of protein found in milk. It exists as a white, powdery substance and can be used for many things, such as baking or preparing ice cream.

What are casein protein side effects?

A: Casein protein is a type of milk protein found in dairy products such as cheese, yogurt, and ice cream. It can cause side effects like bloating, gas, constipation, or diarrhea.

What are casein proteins, and why are they important in food?

A: Casein proteins are a type of protein in milk, consisting of two main components. One is casein (80% or more), and the other one is whey. The structure of these proteins makes them very stable at room temperature, making them good for mixing into things like creams and sauces.

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