Casein is one of the most commonly used protein powders amongst athletes, and yet one of the least understood. Below, we’ll explain in simple terms what casein is, why it’s digested slowly, when to use it, and how it differs from whey.
What is casein?
Casein is the main protein in cow’s milk and accounts for around 80 per cent of the total milk protein. It is a complete protein, which means it contains all the essential amino acids.
The remaining 20 per cent of the milk protein is whey. Casein comes in various forms. Micellar casein is the least processed, meaning the protein structure remains largely intact. At Ekopura, our organic micellar casein comes from organic cow’s milk and is certified organic by SKAL, in accordance with European legislation on organic production. The plain variety contains just one ingredient: casein, with no added flavourings, colourings or sweeteners.
How does slow-release protein (casein) work in your body?
Casein is digested slowly: in the acidic environment of the stomach, it clumps together to form a gel, causing the amino acids to be released gradually over several hours. This is why casein is referred to as a slow-release protein.
This is a factual difference in digestion rate, not a magical effect. Whereas more rapidly digestible proteins release their amino acids within a short time, casein does so over a longer period. This makes it a practical choice when there’s a long gap between meals, for example overnight.
What is the difference between casein and whey?
Casein and whey both come from milk and are both complete proteins. The main difference lies in the rate of digestion: whey is absorbed quickly, whereas casein is absorbed slowly.
| Characteristics | Whey | Casein |
|---|---|---|
| Source | Milk (whey, ~20%) | Milk (~80%) |
| Digestion rate | Fast | Slow, over several hours |
| Complete protein | Yes | Yes |
| Texture in a shake | Thin to creamy | Thick and creamy |
| Common time to use | Around training time | Between meals or before bed |
Many people combine the two: whey around training and casein at a quieter time. So they complement each other rather than one being better than the other. If you’d like to know more about the fast-acting variety, take a look at our whey protein.
When is the best time to take casein?
Casein is often chosen at times when there’s a long gap between meals, such as before bed. The reason is simple: because it’s digested slowly, the amino acids are released gradually.
There’s no single ‘best’ time that applies to everyone. It depends on your daily routine and your total protein intake throughout the day. Some people take casein in the evening, others as a snack during the day or between workouts. What matters is that you get enough protein to suit your goals, rather than the exact time of day.
How much protein do you need each day?
For the average adult, the recommended intake is around 0.8 grams of protein per kilogram of body weight per day. Those who exercise intensively or want to build muscle mass often need more, in the region of 1.4 to 2.0 grams per kilo.
Most people get plenty of protein from their regular diet. A protein powder such as casein isn’t essential, but it’s a handy supplement if you’re struggling to get enough from your meals alone, for example on busy days or during periods of intensive training.
Does casein contribute to muscle and bone health?
Casein is a source of protein. Protein contributes to a growth in muscle mass. Protein contributes to the maintenance of muscle mass. Protein contributes to the maintenance of normal bones.
Do keep a level head, though: it’s about your total protein intake over the course of the day, not just one shake. Casein is simply a way to top up that intake, alongside, for example, meat, fish, pulses or other protein powders. Training and nutrition work together; a supplement doesn’t do the job on its own.
How do you use casein in a shake or recipe?
For a shake, mix casein with water or plant-based milk. Because it’s thicker and creamier than whey, it’s also well suited to baking and desserts.
Think of protein pancakes, bars, muffins or a creamy protein fluff. For the latter, we’ve compiled five recipes in our article on protein fluff recipes. This way, you can get your protein without having to drink the same shake every time, making it easier to stick to your routine.
Who is (or isn’t) casein suitable for?
Casein comes from milk and is therefore not suitable if you want to avoid dairy or follow a vegan diet. It naturally contains milk sugar (lactose), although this is limited in protein powder.
Do you follow a plant-based diet or have a sensitivity to dairy? If so, a vegan protein is the better choice. As with our casein, there’s also a certified organic plant-based option: our organic vegan protein (pure fava). If you’d like to know more about protein and exercise, read our article on nutrition for your training goals.
Frequently asked questions about casein
What exactly is casein?
Casein is the main protein in cow’s milk, accounting for around 80 per cent of the milk’s protein content. It is a complete protein containing all the essential amino acids and is digested slowly.
Is casein the same as whey?
No. Both come from milk and are complete proteins, but whey is digested quickly, whilst casein is digested slowly, over several hours.
Can you take casein during the day as well?
Yes. There’s no set time for taking casein. Many people choose to take it before bed or as a snack, but it’s just as suitable during the day.
Is casein suitable for vegans?
No, casein is a milk protein and therefore not plant-based. Anyone avoiding dairy is better off choosing a vegan protein powder.
Organic casein from Ekopura
Are you looking for a casein powder without unnecessary additives? Our organic casein (plain) contains just one ingredient, with no added flavourings, colourings or sweeteners, and is certified organic (SKAL). Are you unsure whether to choose casein, whey or a vegan protein? Base your choice on your diet and the time of day you wish to consume the protein. View the full range in the casein collection.
