What’s the Difference Between Casein and Whey Protein?

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Casein and whey are the two most popular proteins in the fitness world.

Both come from milk and help you build muscles. They are also rich in essential amino acids, bioactive compounds, and other nutrients.

  1. But what is the difference between casein and whey protein?
  2. Do they provide the same results?
  3. Which one is better?

Today, we are going to answer all your questions on whey and casein. You will learn-

  • The similarities between casein and whey protein
  • The difference between casein and whey protein
  • How our bodies react to both proteins
  • Which one is best for muscle-building
  • When to take casein and whey protein

First, we will discuss a bit about both proteins.

What is Casein and Whey Protein

Whey and casein originate from milk. They are the byproduct of cheese-making. When you add acids (lemon juice will do) and special enzymes to milk, you get two things-

  • The coagulated solid known as casein
  • The clear liquid is known as whey (the liquid that floats on top of yogurt)

Manufacturers wash and dry the solid casein to powder form and sell it as casein protein. The solid is also used to make dairy products like cottage cheese.

The liquid whey also undergoes drying and turns into a powdered whey protein supplement. Milk contains 80% casein and 20% whey protein by weight.

Here’s the nutritional makeup of each protein:

  Whey Casein
Nutrients Per Scoop (weight) 1.1 ounces   1.2 ounces
Calories 110 120
Fat 1 gram 1 gram
Carbohydrates 2 grams 4 grams
Protein 24 grams 24 grams
Iron (% of the Reference Daily Intake) 0% 4%
Calcium (% of the Reference Daily Intake) 8% 50%

  Now, let’s discuss the similarities.

Similarities Between Casein and Whey Protein

  • They have a similar amino acid profile
  • The protein content is the same in both whey and casein
  • Both help in muscle growth and recovery
  • Both have a few other health benefits

Here we will talk about the added health benefits of casein and whey protein. But if you must know, none of the benefits are related to muscle-building.

Health Benefits of Casein and Whey Protein

Casein has many bioactive compounds that have positive effects on-

  • Immunity
  • Digestive system
  • Reducing blood clots
  • Lowering blood pressure levels

The compounds also bind with minerals for better digestion and absorption.

Now let’s come to whey protein. Whey is rich in immunoglobulins that also strengthen our immunity. They also act as good bacteria and kill harmful viruses and microbes. Immunoglobulins may also inhibit tumors and cancer. They even play a role in transporting nutrients like vitamins in our bodies and in their digestion.

One thing to note here is, the immunoglobulins may not be active in whey supplements. So, you might not get any health benefits associated with them.

That’s about it! From here, we have many dissimilarities that require special attention. The differences are what’s going to matter for which you should take for your fitness goals.

The Difference Between Casein and Whey Protein

We will cover the differences in pointers. Then we will go on to explain how that affects your choice. So here’s the important differences you should know about-

  • Our bodies absorb whey protein way faster than casein
  • Whey has a high concentration of amino acids leucine, valine, and isoleucine
  • Casein has more of phenylalanine, methionine, and histidine

Now, let’s find out how the difference between casein and whey protein affects your choice and use.

Casein and Whey Protein Absorption Rates

In our detailed analysis of whey, you saw how quickly our bodies absorb whey protein. In fact, our bodies have an absorption rate of 100% in the first 10 minutes.

According to Bodybuilding.com, our bodies need just 20 minutes to digest, absorb, and metabolize whey protein.

Within 60-minutes, the whey is utilized entirely for protein synthesis. As a result, whey provides an instant peak of amino acids needed by our bodies to build muscle mass.

On the contrary, casein is not a fast-absorbing protein. It takes around 3 – 4-hours for casein to reach peak levels of amino acids and protein synthesis. Casein provides us with a steady flow of amino acids and protects existing muscles from breaking down.

Casein and Whey Protein Amino Acid Profile

Both casein and whey protein has a similar amino acid profile. You will find the same amino acids that you need for protein synthesis and muscle-building. But their concentration differs!

Whey protein is high in leucine, the amino acid responsible for facilitating protein synthesis.

According to Healthline, whey protein leads to higher levels of muscle synthesis compared to casein.

Research also points to the same conclusion, especially when combined with workouts.

That covers the difference between casein and whey protein. Now, let’s see how they affect our choice of protein.

Whey Protein is Best For Muscle Building

If we want to build muscles and aid recovery, whey is the way to go! This is mostly for three reasons.

We Absorb Whey Protein Rapidly

First, whey is one of the fastest absorbing proteins. When we exercise, our bodies breakdown muscles. At those times, we need a fast-absorbing protein to provide an instant boost of amino acids. The amino acids then help in protein synthesis that builds muscle mass and prevents muscle loss.

As you saw above, we absorb whey faster than casein. As a result, the whey protein reaches our muscles when we need them most, i.e., right before or after exercising. That leads to quick protein synthesis, adding to muscle size and aiding recovery.

Whey Protein is High in Leucine

Whey protein has the highest concentration of BCAAs, including leucine. We have already told you how leucine promotes protein synthesis, on a higher level than casein.

Whey Protein Boosts the Levels of Growth Hormones

In studies, whey protein has been found to boost the release of anabolic or growth hormones. Anabolic hormones help our muscles synthesize protein. Whey protein increases the anabolic hormones, resulting in more protein synthesis that adds to muscle mass.

What Does Science Say

Research also seems to back up the conclusions we discussed above. In a study, researchers assessed the effects of casein and whey protein on protein synthesis and degradation (the breakdown of protein). The results of the study concluded-

Whey enhances protein synthesis by 68% and has no effect on protein degradation

Casein reduces protein degradation by 34% but has no effect on protein synthesis

In short, whey protein is much better than casein if your goal is muscle-building because-

  • It’s high in muscle-building amino acid leucine
  • Our muscles use whey more effectively to build muscles
  • Whey promotes the release of growth hormones

Best Time to Take Whey Protein

The best time to take whey protein is within 15 – 30-minutes of working out. This helps you take advantage of the “anabolic window” when our bodies absorb protein at high rates.

Also, our bodies absorb and use whey for protein synthesis well within 1-hour. So, taking it right after working out provides the best results in terms of muscle growth and recovery. You can read more about the implications of the timing of whey consumption here.

Now, that leaves us with the case of casein! We know casein is also a high-quality protein and has similar results. So, why and when should we take casein protein?

Casein Supports Muscle Building Goals

Casein is also good for muscle-building but on a different note.

We know casein is a slow-absorbing protein. It needs 3 to 4-hours to peak and returns to baseline within 7-hours. That means casein is released slowly and provides us with a continuous supply of amino acids over many hours.

So, casein can be the ideal protein to take when you are inactive. Being slow-digesting, it is also good for keeping you satiated and reducing cravings. Also, you can reduce protein degradation by 34%, as indicated by the above study.

The Best Time to Take Casein

The best time to take casein is before you hit the bed.

The casein will slowly release into your bloodstream and provide a steady supply of amino acids to your muscles. As a result, your muscles can synthesize protein all through the night and prevent muscle breakdown.

You will also add to muscle mass, but not as effective as whey.

Note: It’s not a good idea to take casein right before or after working out. At those times, our bodies need fast-absorbing proteins like whey. Having casein after working out will prevent muscle loss, but won’t add to your muscle mass.

Final Thoughts

Casein and whey protein are both muscle-building siblings, but with varied results.

You can take whey protein right after working out to boost protein synthesis, repair tissue, and increase muscle mass.

On the other hand, casein can complement your muscle-building efforts by preventing protein degradation.

Some people also take a combination of casein and whey protein to get the best of both forms. But we don’t recommend that as it ruins the whole fast-absorbing capabilities of whey. So follow our advice and maintain the timing of casein and whey consumption for optimum results.


Does casein protein make a difference?

Casein can also help you build muscles, but not as effective as whey. Casein is more suited for periods when you are approaching fasting, like before going to bed. This way, your body receives a slow and steady supply of amino acids to build and repair muscles all night long. Stick to whey for your workout shakes.

Why is casein protein more expensive than whey?

Whey is the byproduct when you separate the cheese from milk. A lot of whey is produced as a byproduct in different dairy industries. But to get casein, you specifically need to make it from the cheese. As a result, casein costs more than whey.

Is it okay to take casein protein in the morning?

You can take casein for breakfast without any issues. However, if you plan to work out right after, then choose whey instead of casein. Our bodies need fast-absorbing protein like whey while we exercise to build muscles. Casein is very slow to absorb and not fit for the purpose.

Can I mix whey and casein?

Don’t mix whey with casein if you plan to work out soon. Our bodies take 3 – 4-hours to absorb casein. Adding it to whey will ruin the effectiveness of whey. However, you can mix the two on your rest days or when you don’t exercise.

How much casein should I take a day?

You can take 25 – 30g of casein per day without any worries. You may even consume more depending on how active a lifestyle you lead. People who are more active need more protein.

What foods are high in casein protein?

Casein is only available in milk and milk products. That includes butter, cheese, curd, and even ghee.