Can You Mix Whey Protein And Casein? (Follow These Tips)

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While several supplement brands stack different ingredients together, you often don’t see them mixing whey protein and casein protein.

So, can you mix whey and casein together yourself?  Mixing casein and whey is a good option to get a constant protein release. The point of mixing casein and whey is to get the benefits from the fast-acting release (whey) and the slow-acting release (casein) to get the ultimate amino acid supply throughout the day. By combining them, it leads to improved muscle mass.

However, if you are going to mix whey and casein yourself, there are some specific instructions you should follow so you don’t impact your goals.

In this article, I will explore everything related to mixing casein and whey, including:

  • Pros & cons of mixing whey and casein
  • Who should consider mixing whey and casein
  • How to combine whey and casein
  • Common brands that offer a mix of casein and whey protein 

Why Would You Mix Whey Protein And Casein?

Both casein and whey are derived from cow milk. Casein is the most common protein found in milk, compromising 80% of the protein content. In comparison, whey represents 20% of the total protein in milk. 

Although they come from the same place, both have different benefits when ingested.

Casein Protein

Casein tends to be considered a slow-release protein. It roughly takes around 3 hours to get the peak amino acids from casein. It is harder to digest, which means you get a steadier release of amino acids in your bloodstream. This seems to be beneficial during a fasting state, for example, when you sleep

Casein is said to be anti-catabolic, which means it prevents your muscles from being broken down to provide energy, especially during a fasted state (greater than 3 hours). 

Whey Protein

On the other hand, whey is a more fast-release protein, and it gets quickly absorbed and used in the body. It usually takes around 30 minutes to have the amino acid peak. That is why it is best to take after a hard training session. Since it is fast-release, it helps repair and grow your muscles. That is why it is said to be anabolic (muscle-building). 

For those that are looking to maintain or grow their muscle mass, making a combination of whey and casein seems to have several benefits… 

Benefits of Mixing Whey Protein and Casein

Pros vs Cons of mixing whey and casein

Promote More Muscle Gain

The main benefit of mixing whey and casein is that you get a steady amino acid release during the day. This ensures that your muscle mass is preserved during long hours of fasting.

A study done with 36 healthy adult males were given a 10-week resistance training program and split into three different groups: 

  • A group that took a combination of whey and casein
  • A group that took whey, BCAA, and glutamine
  • A group that took a placebo 

It showed that those that had a combination of whey and casein had an average muscle mass gain on average of around 2kg, compared to a 1 kg muscle loss in the placebo group, and 0 kg gained in the whey and glutamine group. 

Increase Fullness

One of the other benefits of having a combination of casein and whey is that it provides fullness. 

Protein tends to be digested slower compared to carbs. 

Therefore, if you are less hungry during the day, it means that you are less likely to eat more calories, which leads to weight loss. 

Having both a fast and slow-release ensures that your stomach feels full during longer periods of dieting. 

Drawbacks of Mixing Whey Protein and Casein

Stomach Issues

The only reason I would advise not mixing whey protein and casein together is if one makes you have stomach problems. 

Although whey and casein are very low in lactose, some people have a hard time digesting either one. Thus, if this is the case, you shouldn’t consider mixing them. 

Is It Safe To Mix Whey Protein And Casein?

Mixing casein and whey is safe as both come from the same source (milk).  

In fact, when you drink a glass of milk, you are drinking both casein and whey protein.  The only difference with the supplement version of whey and casein is that the carbs and fat have largely been extracted from the powder, so what you’re left with is mostly pure protein.

As such, there is no reason why you shouldn’t consider mixing whey protein and casein from a safety perspective. 

Misconceptions About Mixing Whey Protein and Casein

As published on certain sites, there seems to be a general myth that you cannot mix whey protein and casein protein since they can compromise amino acid absorption in the body. 

Since whey is absorbed faster than casein, people tend to think that mixing them will make the protein absorption of whey slow down.  As such, you’ll sometimes see people recommending having one or the other, but not both. 

However, this is not the case. 

A study looked at the absorption and amino acid release of both casein and whey, and it found that there was no compromise whatsoever. Whey was still absorbed faster than casein, maintaining their main benefits. 

How To Combine Whey Protein With Casein?

combining whey protein with casein by having them in the same intake or mixing them during the day

There are two ways that you can combine whey and casein: 

(1) You can either have them in the same intake, or 

(2) Have a mix of them during the day. 

Either choice is fine to have. 

However, please consider the following factors when determining how best to combine them for your goals: 


The dosage of them depends on your total protein intake. Remember that they are called protein supplements for a reason. They help you achieve your total protein intake if you find it hard to do.

The ISSN recommends a protein intake of 1.6-2.0 g of protein per kilogram of bodyweight. This means that for a person that weighs 70 kg, their daily intake is 112-140 g of daily protein. A regular scoop of protein has 25 g, representing around 26% of the total protein intake.

If you have a hard time reaching this daily amount, then you can add a supplement. If you are going to mix casein and whey, you can do it 50/50. This means having half a scoop of whey combined with half a scoop of casein. 

The benefits of increased muscle mass can be achieved with a smaller casein intake though. In a study, those that increased an average of 3% muscle mass had 40 g of whey and only 8 g of casein

However, practically speaking I prefer to do the 50/50 combination since it is less of a hassle when using the protein scooper. 

Time of Day

In terms of protein timing, mixing whey protein and casein will depend on your daily schedule and training sessions. 

If you go to the gym in the morning and then have meetings all day long, you can combine whey and casein after your workout. This way, you get the fast-release protein immediately after training, but ensure that you will have a steadier amino acid release during your meetings with the casein.

Mixing them together doesn’t necessarily mean in the same shake. You can also combine them throughout the day.

This means that you can have the whey protein after training (whether it is in the morning or at night) and then have the casein during the day when you have to work. In other words, take them separately but combine them during the day.

Finally, the other time of day I recommend having the mix is before going to bed. If you are not that hungry at night, you can have a combination of both. Create a protein shake (with carbs and healthy fats) with a mix of casein and whey. This helps you release protein quickly and ensure a steadier release during your sleep. 

Who Should Consider Mixing Whey Protein & Casein?

who should consider mixing whey protein & casein?

Anyone can have this combination of proteins.

However, there are two situations where I emphasize having this protein blend to a greater extent.

People Who Have Busy Schedules

If you have a schedule that is very busy during the day, making for long hours of fasting (more than 3 hours), then adding a mix of whey and casein into your diet ensures that even if you are in a meeting during the day and cannot eat, you are still getting a steady amino acid release.

Whey protein gives you the immediate protein you need (for example if you have it as a breakfast), and the casein will get your protein levels steady all morning until your next mealtime. This leads to less hunger and maintaining your muscle mass. 

People Who Lose Muscle Mass Quickly

If you tend to lose muscle mass very quickly if you aren’t consistent with your diet, or hitting your daily protein goal, then I’d suggest mixing whey and casein together. 

This seems to be the case for individuals with a leaner body type, and those that consider themselves “hard gainers”.   

For these people, I suggest having a whey protein shake after training, and a casein protein shake before going to bed. 

Can You Buy Whey Protein & Casein Pre-Mixed?

whey protein and casein pre-mixed

If you want to eliminate the hassle of making the combination of both proteins. Certain brands already offer a combined protein supplement. 

Here are my top 5 brands that offer you a mix of whey and casein all in one container.

  • Naked Protein. It is from grass-fed cows, and also contains eggs whites. It has no additives or artificial flavors. I love this brand because they’re extremely transparent with how their products are produced, everything from the ingredients to the supply chain.
  • Combat Protein – Muscle Pharm. It is also a mix of whey, casein, and egg protein. This protein blend is great for those looking for the best price per scoop.

What Else Can You Mix Whey Protein With?

About The Author

Brenda Peralta

Brenda Peralta is a Registered Dietitian and certified sports nutritionist.  In addition to being an author for, she fact checks the hundreds of articles published across the website to ensure accuracy and consistency of information.

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