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Casein vs Whey Protein: Difference Explained

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You may be wondering, is whey or casein better? These are 2 of the most widely used protein supplements available, and are very similar in many ways. 

This can make the decision between casein vs whey protein difficult. In this article, we’ll be covering both supplements in-depth to help you make a more informed decision. 

The difference between casein vs whey protein largely comes down to absorption. Casein is a slow-release protein, meaning it is absorbed by the body slower than whey. However, this won’t make a huge difference for most people looking to build muscle.

What Is Casein Protein?

Casein (commonly referred to as “micellar casein”) is similar to whey, as it is a protein derived from milk. Casein and whey are the 2 types of protein found in milk, and are both dried and sold as protein supplements. So, what makes casein different from whey?

The main difference between casein and whey protein is the absorption time. Casein is commonly referred to as a “slow-release” protein because it takes longer to digest than whey. Casein protein increases plasma amino acids for ~7 hours compared to ~3 hours for whey

However, it’s worth noting these increases are less dramatic than they are for whey, despite taking course over a longer time period. The lower leucine content in casein also leads to a difference in anabolic response. 

Because of casein’s slow-release properties, it is frequently branded as a protein to take before sleep. Studies have shown that taking casein before bed is useful for exercise recovery

However, these benefits are likely more thanks to casein being a solid source of complete protein, and not because of its slow-release properties. In fact, there does not appear to be any significant difference between whey and casein in terms of performance enhancing effects

It’s also likely that casein has similar effects on muscle protein synthesis regardless of when it’s taken in the day.

Using Legion Athletics Casein Protein Powder as an example of Casein’s nutritional information, you can expect 26g of protein, 2g of carbs, and 0g of fat in each serving, for a total of 120 calories. 

This product is also ~$2 per serving, although this is likely on the higher end of the average cost for casein.

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What Is Whey Protein?

As mentioned above, whey and casein are both derived from milk, and as a result are very similar products. With that being said, whey is far and away the more popular choice for protein powders, being the standard choice for more people.

The main difference is absorption time, with whey being a faster protein. While casein has more moderate effects on plasma amino acids for ~7 hours, whey has more potent effects for ~3 hours. 

Of course, this likely evens out with both supplements showing very similar overall effects on performance. However, whey shows slightly better levels of muscle protein synthesis. It’s also worth noting that taking whey with carbs and fats will slow down the absorption time. 

There are 2 kinds of whey protein: isolates and concentrates. Isolates are a purer form of whey with less carbs and fats. They usually have a protein concentration of 90% or higher

Concentrates are slightly less refined, usually with slightly more calories from carbs and fats. These will usually have a protein content around 80%. Because of this, concentrates are typically better for bulking, while isolates are ideal for cutting. Isolates are also typically slightly more expensive than concentrates. 

Whey is most often branded as a post-workout recovery drink, but it should be made clear that protein timing is not as important as it’s often made out to be. It’s much more important you simply get enough protein throughout the day if you’re trying to build muscle. 

While protein supplements also aren’t necessary for building muscle, whey protein is a great way to get some extra protein in through a convenient and delicious drink. 

Using Transparent Labs Whey Protein Isolate as an example, we can take a look at the nutritional information of a high-quality whey isolate. You can expect 28g of protein, 1g of carbs, and 0g of fats, with a total of 120 calories. 

It is also ~$2 per serving, although you can certainly find concentrates for much cheaper in the $1-1.50 range. 

Protein Isolate

Casein vs Whey Protein

Overall, casein and whey protein are very similar supplements with the main difference between the two being how they are absorbed in the body. In terms of macros, and price they are very similar, although whey has slightly more variety in terms of flavors on average. 

Overall, when considering whey protein vs casein, whey will be the go-to for most people, although casein is certainly an excellent alternative, especially for those allergic to whey. 

If you want to maximize the slow-digesting benefits of casein (more sustained boost in nitrogen balance) with the fast-digesting benefits of whey (greater peak in protein, higher leucine content), you can definitely mix them together!

CriteriaCaseinWhey
AbsorptionCasein takes around 7 hours to be fully absorbed by the body, leading it to be commonly referred to as a “slow-release” protein.Whey takes around 3 hours to be fully absorbed, so it is commonly referred to as a “fast protein”. It’s worth noting that it will absorb slower when taken with carbs and fats.
MacrosCasein will typically contain around 25g of protein per serving with minimal fats and carbs.Whey differs in terms of macros depending on whether you’re getting a concentrate or an isolate. Whey’s protein content can range from 20-30g per serving on average.
PriceBased on Legion’s product, a high-quality casein is about $2 per serving, although you can likely find cheaper options.Based on Transparent Labs, a great whey isolate will go for about $2 per serving as well. There are plenty of cheaper options available, especially for concentrates, closer to $1 per serving.
FlavorCasein is typically more limited in its flavor options, although there is a decent amount of variety available.Because whey is the more popular supplement, there is significantly more variety in flavor available when compared to casein.

1. Absorption

Casein is a slow-digesting protein, while whey is a fast-digesting protein. This means there is a difference of several hours in how fast our bodies are able to process these different supplements. 

While this has led to casein being marketed as a “nighttime protein”, it doesn’t appear this makes a significant difference in the outcomes these proteins produce. 

2. Macros

Casein and whey both have very similar macros, which is to be expected considering they come from the same source. Casein will typically have around 25g of protein per serving based on Legion’s product. 

A high quality whey isolate will have close to 30g of protein (Transparent Labs has 28g), but concentrates have a range from around 20-25g on average. However, whey does have a higher leucine content, which is closely associated with a great anabolic response, meaning whey is a bit superior for muscle protein synthesis.

l-carnitine supplement

3. Price

Another point where casein and whey are very similar, a high-quality casein and whey isolate will both cost you around $2 per serving. If you’re looking to save some money, you can easily find a whey concentrate for much less at closer to $1 per serving.

4. Flavor

Because whey is the more overall popular supplement, it is much easier to find it in a wide range of flavors when compared to casein. For reference, Legion’s Casein comes in 5 flavors, while Transparent Labs’ whey comes in 12!

Casein vs Whey Protein: Summary

Overall, casein and whey protein are very similar supplements given they are derived from the same source. In terms of absorption, casein will take slightly longer than whey, but this is the main difference between them. 

They are similar in macros and price, although whey has slightly more flavor variety on average. Overall, when deciding between micellar casein vs whey, most people will likely choose whey. With this being said, they are both excellent choices for a protein supplement. 

preparing supplemeent powder

Pros/Cons of Casein Protein

Positives:

  • Slow release protein may have unique applications for nighttime use
  • Slow release may make casein feel more satisfying than whey
  • Solid protein content and concentration
  • Low carb and fat content makes it good for cutting

Could be better:

  • Often doesn’t come in as many flavors as whey
  • Protein content is typically lower than a whey isolate
  • Relatively expensive
  • Lower leucine content makes it slightly less anabolic than whey

Pros/Cons of Whey Protein

Positives:

  • High average protein content ranging from 20-30g
  • Isolates especially are great for cutting
  • Wide range of different flavors to choose from
  • Concentrates especially are very budget-friendly 
  • High leucine content makes it more anabolic than casein

Could be better:

  • Can be somewhat expensive, especially for a good isolate
  • Concentrates will typically have a relatively lower protein concentration compared to isolates

Casein vs Whey Protein: When to Use Each?

Casein is commonly branded as a nighttime protein supplement because of its slow-release effects. While some studies have shown it to aid in recovery when taken before bed, it’s possible they would have noticed similar results regardless of when the protein was taken. 

Overall, both casein and whey are great choices for hitting your daily intake goals. While protein supplements aren’t necessary for building muscle, either of these dairy-based proteins are a convenient and reliable way to get some extra protein in. 

Best Whey Protein – Transparent Labs Whey Protein Isolate

Transparent Labs Whey Protein Isolate

Transparent Labs Grass Fed Whey Protein Isolate

Our top pick for a high-quality whey protein supplement is Transparent Labs Whey Isolate. If you’re familiar with Transparent Labs, then you’re likely already aware they produce some of the most consistently high quality exercise supplements around. Their whey isolate is no exception. 

With this being an isolate, you can expect super high protein content and concentration. This product not only has 28g of protein per serving, but at only 120 calories, this gives Transparent Labs a 93% protein concentration by calories and 85% of protein in the scoop. There’s also only 1g of carbs in each serving, making this an ideal protein for cutting. 

Transparent Labs also offers fantastic flavor variety with 12 unique flavors to choose from. Like all of their products, this is also made with no artificial ingredients whatsoever. 

It is also made with 100% grass-fed dairy, which is largely considered to be the healthiest type of dairy available. 

Of course, with this being a premium protein powder, it does come at a decently high price. Each serving of Transparent Labs whey will cost you around $2. 

While you can certainly find cheaper whey protein powders out there, for a high-quality whey isolate, Transparent Labs offers great value for your money.

Best Casein Protein – Legion Athletics Casein Protein Powder

Legion Athletics Casein Protein Powder

casein protein powder
  • Serving Size: 1 scoop (34g)
  • Servings per Container: 30
  • Price per Serving: ~$2
  • Other Ingredients: Calcium, Iron, Vitamin D
  • Suitable for Vegans: No
  • Company Founded: 2014
  • Recommended By AthletesGage Clark, Grant Tinsley

If you’re more interested in trying out Casein, our top pick is Legion Athletics Casein. With a similar stellar reputation to Transparent Labs, let’s see how Legion’s Casein compares to Transparent Labs’ whey. 

In terms of protein content, Legion’s Casein is slightly lower than Transparent Labs’ whey, with 25g per serving. However, it does still offer stellar protein concentration. At 120 calories, it has a concentration of 83% protein by calories and 74% of protein in one serving. This puts it on par with a quality whey concentrate. 

Flavor variety is noticeably lacking compared to Transparent Labs, although Legion still offers a solid 5 different flavors to choose from. Like Transparent Labs, it is also made with 100% natural ingredients. 

This also comes at a similar price point to Transparent Labs at $2 per serving. Again, you can very likely find a cheaper casein product, but it probably won’t be nearly as high-quality as Legion. 

FAQ

Is Casein Better Than Whey Protein?

Not necessarily, with both proteins being fairly similar in most categories, it’s difficult to say which is the better option. 

Although it will largely come down to personal preference, most people will likely end up going with whey because it is the more common supplement and has “whey” more flavors ;-). 

Does Casein Build More Muscle Than Whey?

No, studies have shown that both supplements appear to have nearly identical performance enhancing effects meaning that neither one is better at building muscle than the other. 

Because whey has more leucine, it is more directly anabolic. However, simply getting enough protein throughout the day is more important than things like amino acid breakdown. 

Why Not to Take Casein Protein?

Other than being allergic to the protein, there’s no reason to outright avoid casein as it is a very similar protein source to whey. While whey may be more popular than casein, the difference between whey and casein is not that big. 

The only potential reason you may want to avoid casein is if you’re looking to bulk and want to process the food you’re eating quicker. 

Can You Take Casein and Whey in the Same Day?

Yes, in fact, taking both will give you optimal results (ie. slow steady release from casein, and high peak from whey). 

With this being said, this isn’t necessary if you’re not too concerned about fully optimized protein consumption. Taking one or the other will likely give you similar results in your performance.

Should You Take Whey or Casein for Weight Loss?

Because casein is a slow-release protein, it may be more satiating when compared to whey. However, these differences will likely be minor. 

If you’re looking to take casein or whey for weight loss, both should be effective sources of high-quality, low-calorie protein. 

Conclusion

Casein and whey are 2 very similar dairy-based protein powders that provide similar effects. While casein is a slower-release protein and bit less leucine than whey, the 2 protein types are nearly identical beyond this. 

If you want to optimize the effects of these 2 supplements, you could consider taking both simultaneously. 

If you’re looking for a great whey supplement, we recommend Transparent Labs Whey Protein Isolate, and for a solid casein supplement, try Legion Athletics Casein Protein Powder.

Do you prefer whey or casein? Let us know your thoughts in the comments below!

Also read:

References:

  1. JOSE ANTONIO, ANYA ELLERBROEK, COREY PEACOCK, TOBIN SILVER, “Casein Protein Supplementation in Trained Men and Women: Morning versus Evening” National Library of Medicine, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5421981/ (accessed May, 2017), 10(3): 479–486.
  2. Phys Act Nutr, “Pre-sleep casein protein ingestion: new paradigm in post-exercise recovery nutrition” National Library of Medicine, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7451833/ (accessed Jun, 2020), 24(2): 6–10.
  3. Kristin M. Dugan, Mallory McAdams, Morgan Lewing, Cliffa Foster, Colin Wilborn,  Lemuel W. Taylor IV, “The Effects of Pre- and Post-Exercise Whey vs. Casein Protein Consumption on Body Composition and Performance Measures in Collegiate Female Athletes” University of Mary Hardin-Baylor, https://digitalcommons.wku.edu/ijesab/vol2/iss2/24/ (accessed 2010).
  4. “How to Cite Sources in Oxford Style,” Georgia State Website Security, https://recreation.gsu.edu/2023/03/31/the-rundown-on-protein-powders/
  5. “Grass-fed cows produce healthier milk” University of Minnesota Extension, https://extension.umn.edu/pasture-based-dairy/grass-fed-cows-produce-healthier-milk
  6. Photos made by Torokhtiy Media Team.

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Jacek Szymanowski

Author: Jacek Szymanowski

Certified Nutritionist,
M.Sc.Eng. Biotechnology
Performance Architect,
Strength and Conditioning Specialist

Experience: 20 years

With over 30 years of fighting experience, specialization in nutrition coaching for athletes, and expertise in metabolic health and dietary strategies, Jacek offers a comprehensive approach to optimizing your performance and well-being. Backed by a Master of Science degree in Biotechnology, Jacek remains at the forefront of scientific advancements, ensuring that his coaching is always evidence-based and up-to-date.

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