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.
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.
Casein vs Whey Protein
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.
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.
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.
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.
Pros/Cons of Casein Protein
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
Lower leucine content makes it slightly less anabolic than whey
Pros/Cons of Whey Protein
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
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
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.
Is Casein Better Than Whey Protein?
Does Casein Build More Muscle Than Whey?
Why Not to Take Casein Protein?
Can You Take Casein and Whey in the Same Day?
Should You Take Whey or Casein for Weight Loss?
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.
Do you prefer whey or casein? Let us know your thoughts in the comments below!
- 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.
- 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.
- 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).
- "How to Cite Sources in Oxford Style," Georgia State Website Security, https://recreation.gsu.edu/2023/03/31/the-rundown-on-protein-powders/
- "Grass-fed cows produce healthier milk" University of Minnesota Extension, https://extension.umn.edu/pasture-based-dairy/grass-fed-cows-produce-healthier-milk
Why Trust Us?
Author: Jacek Szymanowski
S&C movement specialist
Experience: 20 years
With my 30 years fighting experience, specialization in nutrition coaching for athletes, expertise in metabolic health and dietary strategies, I bring a comprehensive approach to optimizing your performance and well-being. Backed by a master's of science degree in biotechnology, I stay at the forefront of scientific advancements, ensuring that my coaching is always evidence-based and up-to-date.
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