Whey and casein are two dairy proteins, both obtained as by-products during the cheese-making process. Both proteins are quite helpful in building and protecting muscles. That is why many bodybuilders and athletes take them regularly.
Since both are proteins, many people cannot decide which of them is better for their health. If you also have this confusion then keep reading to find which is better whey or a casein supplement?
Whey protein vs. Micellar casein protein
Whey protein powder is derived from cow milk during the cheese production process. It makes 20% of the total protein content of cow milk. Whey is the watery part of the milk that is left behind after milk has been curdled or strained during the cheese-making process. The liquid you notice in your yoghurt jar also has whey in abundance.
The liquid is processed and converted into powder form which is sold in the market as a popular whey supplement. Whey exists in three forms based on the difference of concentration. These forms are whey protein isolate, whey protein concentrate, and whey protein hydrolysate. Whey protein isolate has the highest concentration of whey.
Micellar Casein protein is also derived from cow milk. It makes 80% of the total protein content of the milk. It is a jelly-like or curdled substance that is left behind as a by-product during the cheese production process. This material is processed, purified, and converted into a powdered form which is available in the market as a casein supplement.
Casein is usually available in forms. One is called micellar casein protein while the other is called casein hydrolysate. Micellar casein protein digests slower compared to the casein hydrolysate which is pre-digested.
How do both proteins work?
One of the main differences between casein and whey is how they digest in the body. Whey dissolves faster in the body and absorbs in your body within 20 minutes of ingestion. It provides amino acids to the muscles instantly and assists them to build muscles after a workout. That is why whey is called an anabolic protein.
On the other hand, micellar casein protein is a “slow-release” protein. A casein supplement digests slowly and converts into a curd-like structure in the acidic environment of the stomach. It keeps providing amino acids for up to several hours after its ingestion. That is why a casein supplement is more helpful in preventing muscle breakdown that may occur due to the lack of protein. It is referred to as an anti-catabolic protein.
Similarities between casein and whey
Both proteins are derived from cow milk and are obtained as by-products of the cheese-making process. Whey is in the liquid part of the milk while casein is in the curd part of the milk. Both are separated from the milk and converted into the supplement.
There are two kinds of amino acids – essential and non-essential. Your body can make the non-essential amino acids on its own but it depends on the external sources for the essential amino acids. Both micellar casein protein and whey protein are called complete proteins because both have all the essential amino acids.
Differences between casein and whey
Casein protein consists of several bioactive peptide chains. These peptides support the digestive and immune systems.  They are also known to be very effective in lowering high blood pressure.  Micellar casein protein also provides calcium and phosphorus which are important minerals that play several roles in the body.
Whey contains other proteins that are immunoglobulins in nature. They are antimicrobial which means they can slow down the spread of microbes by either killing them or reducing their growth. 
Effect on building muscles
Both casein and whey are effective in building muscles. But due to a difference in their chemical composition, several studies prove that whey protein is more effective for building muscles.
It is mainly because of the high branched-chain amino acid content of the whey protein. It has more of the leucine amino acid compared to the casein protein.  Leucine kick-starts the process of muscle protein synthesis. That is why gym-goers and bodybuilders prefer taking whey supplements right after a workout when their bodies need whey the most.
Which is better: casein or whey protein?
Both casein and whey proteins are healthy and beneficial in different ways. We cannot say one is better than the other. However, you should always keep in mind your goals before buying any of these supplements.
The purpose of a whey supplement is to boost your muscle growth by providing your body with the essential amino acids it needs to build muscles. That’s why it is suggested to take a whey protein shake right after a workout.
On the other hand, micellar casein protein is effective in preventing muscle breakdown. Muscle breakdown occurs when your body lacks protein. Under such cases, your body starts breaking down its own muscle protein. Due to this reason, people take the casein supplement as a bedtime snack. Casein keeps releasing amino acids for several hours while you sleep.
Taking both whey and casein protein
After seeing the different roles of casein supplement and whey supplement, it makes more sense to have both supplements. Whey will help you to build muscles faster while casein supplement will assist you to maintain muscle growth. When combined, both proteins can help you stimulate muscle growth and keep them in a healthy shape.
The bottom line
Casein and whey have a few similarities and a few differences based on their structure, composition, and roles in the body. If you want to build muscles fast then go for the whey supplement. But if you want to protect your muscles from breaking down then choose a casein supplement. You can also use them together to meet your fitness goals more effectively.
- Antimicrobial activity of two peptides casecidin 15 and 17, found naturally in bovine colostrum (nih.gov)
- Casein-Derived Lactotripeptides Reduce Systolic and Diastolic Blood Pressure in a Meta-Analysis of Randomised Clinical Trials (nih.gov)
- Multifunctional capacity and therapeutic potential of lactoferrin (nih.gov)
- Influence of the protein digestion rate on protein turnover in young and elderly subjects (nih.gov)