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Whey Protein vs. Casein Protein: How are They Different from Each Other?

Protein is one of the macronutrients that your body needs to perform different important tasks. Taking a protein supplement to increase your protein intake is an effective way of improving your overall health.

There are many forms of proteins available in the form of the market. Two of the most popular and widely consumed protein forms are whey and casein protein. Both have a few similarities and many differences. Let’s see their differences and similarities to identify how they truly differ from each other.  

Grass Fed Whey Protein Powder  Grass Fed Micellar Casein Supplement

The similarity between casein protein and whey protein

The main similarity between these popular forms of proteins is that both of them are derived from milk. Cow milk has 20% whey protein and 80% casein protein. [1]

These proteins are separated from the milk during the cheese-making process. During this process, a solid and a watery byproduct are achieved. The solid byproduct contains casein, while the watery byproduct contains whey. These byproducts are passed through different processes in order to purify proteins from them which are then converted into a powdered form that is sold in the market as a supplement.

Both casein and whey proteins are considered complete proteins because both have all the 9 essential amino acids. [2] Your body is unable to synthesize these amino acids and depends on other food sources to have them. Casein and whey proteins are considered healthy sources of all amino acids. You do not have to consume different food items to have all the essential amino acids because you can get them from a single source, AKA, casein or whey protein.

How are they different from each other?

Casein and whey proteins differ from each other on the basis of the following points.

The difference in their absorption in the body

The main difference between these proteins is in their absorption. Casein takes time to fully absorb in the body while whey gets absorbed rather quickly.

Like any other nutrient, protein is also digested into smaller components (in the case of protein, these components are amino acids). These components move freely in your blood and get absorbed by cells, where they are used to perform different tasks.

Studies show that the level of amino acids stays high for up to 5 hours after the consumption of casein. On the other hand, the levels of amino acids stay high in the blood for up to 1 and a half-hour after the consumption of whey protein. [3]

Therefore, casein protein supplements are more suitable as bedtime supplements. Casein will release its amino acids slowly in the bloodstream, which is ideal when you are sleeping. On the contrary, whey is a more suitable post-workout supplement that readily provides your body with the amino acids that it needs to build muscles and repair them.

The presence of different bioactive compounds in both proteins

Casein and whey contain different forms of peptides that are involved in different functions. Casein has peptides that are like angiotensin-converting enzyme (ACE) inhibitors. They also work like ACE inhibitors which are popular drugs used to reduce blood pressure in hypertensive people.

Therefore, casein is known to have the ability to lower blood pressure and inhibit the formation of blood clots which protects against heart disease. [4] Casein peptides are also involved in improving your digestive and immune systems.

On the other hand, the peptides present in the whey protein are actually immunoglobulins that are involved in the defence system. [5] They also reduce the growth of microbes by either slowing down their propagation or killing them. Immunoglobulins of whey protein also enhance the absorption of important nutrients in the bloodstream.

The effect on muscle strength and growth

Whey protein is more beneficial for muscle strength and growth compared to casein protein. It is mainly because of the difference in their amino acid profiles.

Casein has methionine, histidine, and phenylalanine in abundance. On the other hand, whey protein has branched-chain amino acids (valine, leucine, and isoleucine) in abundance. [6] Whey protein boosts muscle growth and strength because its amino acids leucine is known to stimulate the production of muscle protein. So, when you take whey, you provide your body with many essential amino acids and also boost the production of the protein synthesis process in the body. [7]

Why should you consume proteins?

Proteins are involved in many important functions in the body. It helps with metabolism and body repair. It makes several antibodies in the body that protect your body from foreign invading particles. It also makes enzymes that speed up metabolic reactions. Proteins also make several hormones (like insulin) that coordinate signalling processes.

Many studies prove that proteins like whey can help you control your sugar level by increasing your insulin production. [8] Proteins may also help you manage blood pressure. [9]

The bottom line

Casein protein powder and whey protein powders are two of the most popular protein supplements in the world. These proteins mainly differ from each other on the basis of their absorption, chemical composition, and effect on muscle strength.


  1. Bovine milk in human nutrition – a review (
  2. Milk nutritional composition and its role in human health - PubMed (
  3. Influence of the protein digestion rate on protein turnover in young and elderly subjects - PubMed (
  4. A randomized, double-blind, placebo-controlled trial of casein protein hydrolysate (C12 peptide) in human essential hypertension - PubMed (
  5. Antiviral activities of whey proteins - PubMed (
  6. Influence of the protein digestion rate on protein turnover in young and elderly subjects - PubMed (
  7. The leucine content of a complete meal directs peak activation but not duration of skeletal muscle protein synthesis and mammalian target of rapamycin signaling in rats - PubMed (
  8. An increase in dietary protein improves the blood glucose response in persons with type 2 diabetes - PubMed (
  9. Dietary Protein Intake and Blood Pressure: A Meta-Analysis of Randomized Controlled Trials | American Journal of Epidemiology | Oxford Academic (


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