Casein: The Facts You Need To Know
What is casein?
Casein is a term that describes related phosphoproteins of milk. These proteins are common in mammalian milk, constituting 80 percent of cow milk proteins.
The major proteins in milk are casein and whey. These two milk proteins are both excellent sources of all the essential amino acids, but they differ in one important aspect— whey is a fast-digesting protein and casein is a slow-digesting protein.
The Difference Between Whey & Casein
Whey is digested more quickly by the body and may be most beneficial when consumed immediately after workouts. Casein is a slower-digesting protein that is used less efficiently by the body.
Casein and Whey Protein: When to Take?

As a pre-workout or post-workout supplement casein is not going to give you much benefit. That’s when you should take whey protein because your body requires proteins available immediately.
But between meals or before bedtime you don’t have to provide immediate nutrients to your body, so casein protein is more indicated before bedtime or between meals. This way, if you are trying to get the recommended eight hours of sleep every night and you don’t want to wake up in the middle of the night to eat, consuming casein protein just before heading off to bed will ensure your body is getting all it needs. The trickling effect of amino acids into your bloodstream from the casein clot in your stomach will make sure that happens.

What happens to your body for that 7-8 hours you’re laying in bed at night? If you haven’t had any casein protein before bed, then chances are you may be losing some muscle mass. Why? Most of your muscle rebuilding occurs while you’re asleep, not during the day. Without casein protein, you’re liable to lose amino acids from another muscle source to rebuild the damaged muscle.
The best is to take them both at different times during the day to supplement your diet.
Pre-workout: Whey
Post-workout: Whey
Between meals: Casein
Before bedtime: Casein
Most important facts about casein protein (benefits)
- Is a complete protein source
- Stimulates muscle protein synthesis/activates mTOR pathway
- Provides anti-catabolic properties for longer periods of time than rapidly-digesting proteins
- May be a useful appetite suppressor since it provides more enduring satiety than a rapidly-digesting source of protein
- Is a rich source of calcium which may be beneficial for bone health and fat loss
- Individuals looking a convenient and quick way to increase protein intake will derive the most benefit out of supplementing with casein protein

What foods contain casein protein?
Casein is a family of proteins found in cow’s milk. It congeals in your stomach and takes hours to digest, providing a slow release of protein. Solid cheeses have the highest natural content of casein, followed closely by cottage cheese. Cottage cheese is typically the healthier option, as it is available in reduced-fat and fat-free varieties.
Milk is another excellent option, around 80-percent of its protein is casein – like cottage cheese, it is available low fat and fat-free. Combining dairy products in a meal packs a large amount of slow-digesting protein in one sitting. For example, eat a serving of cottage cheese with a glass of milk.
Steak, pork, chicken, turkey, salmon and sole are just some of the options for slow-release protein from the meat category. While the protein in these foods digests slightly faster than casein, meat-based protein breaks down slower than that from legumes or grains.
Casein Protein Powder
If you are pressed for time or simply looking for protein on the go, casein protein powder is a great choice. It is made from pure casein separated from dairy products by a process known as “ultrafiltration.” One 2-tablespoon serving of casein powder can deliver as much as 25 grams of protein at the cost of just 100 calories. It mixes well with water or milk, but drink your shakes right away, as it separates quickly.
There are 3 forms (types) of casein protein
- Calcium Caseinate
- Micellar Casein
- Milk Protein Isolate
Calcium caseinate is the lowest quality among the three forms and is commonly used as a food ingredient. Micellar casein and the casein in milk protein isolate are identical. While micellar casein is 100% casein, milk protein isolate has both micellar protein and whey.
Casein protein is actually the natural, undernatured form of casein that is found in milk. It also makes up 80% of the protein found in milk. The separation process from the milk is called ultrafiltration. This process is done without the use of any chemicals, and it increases the amount of bioactive milk peptides that support immune function along with enhancing muscle growth.
Casein protein also has the ability to form a ball, or gel, in the gut, that provides a constant release of amino acids into the bloodstream. This ability makes casein protein the optimal choice for long lasting anti-catabolic protein.
Given the findings that whey protein stimulates protein synthesis and casein helps decrease muscle breakdown, some supplement manufacturers add both whey and casein to their formulations.