Casein: what it is, how it works, how it is used


Casein is the main protein found in dairy products. Casein can be recognized in the additive counter, but it is also used in cheeses and infant formulas.

Here's an overview of casein, including the potential risks and benefits of adding it to your eating plan.

Gabrielle Vergani / EyeEm / Getty Images

What is casein?

Casein is a complete protein that contains all the essential amino acids that our body needs to function. Pure casein is a tasteless, white solid. All mammals produce casein as a component of milk for their young.

Human breast milk is 40% casein and 60% whey, while cow's milk protein is 80% casein and 20% whey. Because casein binds calcium and phosphorus, milk is a good source of these vital minerals.

Casein is a milk protein produced by mammals.

How Casein Works

As a protein supplement, casein provides our muscles with the full range of amino acids they need to recover from exercise and build strength. After a hard workout, our body repairs the small tears created in our muscle fibers so that they become bigger and stronger.

Adequate sleep and adequate protein intake are essential for muscle recovery. Foods with casein provide additional protein to support muscle tissue .


In isolation, casein is used as the main component in cheese making and as a protein supplement. Bodybuilders can take casein products immediately after exercise or before bed to aid post-workout recovery. Casein is also used to form infant formulas as a substitute for breast milk .

Structure and properties

In nature, casein exists as a suspended molecule in a surrounding liquid. This structure is called a micelle. You can think of a micelle as a small intact bubble mixed with a solution.

There are four subtypes of casein. These include:

  • AS1-Casein
  • AS2-Casein
  • b-casein
  • k-casein

The first three subtypes of casein are sensitive to calcium (all except k-casein). Calcium-sensitive subtypes bind to calcium and phosphorus, transporting these minerals for digestion and absorption in the body. K-casein has a structural function in the casein micelle: it keeps the micelle intact until it is removed by digestive enzymes.

After k-casein metabolism, the micelle coagulates into an insoluble mass. This initial step in digestion actually converts casein into a form that is more resistant to degradation. Because micelles take several steps to break down, casein is considered a slow-digesting protein .


For adults, a casein-based protein shake combined with regular resistance training can promote bone health and muscle development. A glass of milk contains approximately 300 milligrams (mg) of calcium, most of which is found in casein micelles.

Most adults need 1,000 to 1,200 milligrams of calcium each day. Given the dual importance of adequate calcium and protein intake for bone health, foods rich in casein can help prevent osteoporosis .

Not only is casein a complete protein, it is also used by bodybuilders due to its slow absorption. Soy protein and whey protein enter the bloodstream quickly, and casein takes six to seven hours to fully digest .

The reduced rate of digestion of casein ensures a constant supply of amino acids to damaged muscle tissue long after exercise, promoting better recovery. Slow digestion also promotes satiety, helps you feel full longer, and reduces cravings for unhealthy foods.



Cow's milk is one of the most common food allergens that can be a problem for formula-fed babies. Milk allergies usually start in infancy or early childhood, but can develop later in life.

If your child is allergic to cow's milk, your healthcare provider may recommend a hydrolyzed casein-based formula. While its bitter taste is not always preferred, hydrolyzed casein can help children with allergies get the nutrients they need during critical growth periods.

If you are allergic to milk, ask your doctor if you need to be tested to determine the specific proteins responsible for your allergy. You may be allergic to other milk proteins like whey, but not casein.

However, it is better to play it safe. Before you risk your luck with casein, consult your allergist to determine the root cause of your milk allergy.

Allergic reactions to milk should not be confused with lactose intolerance . Many people are intolerant to lactose (the natural sugar in milk), but the casein found in yogurt or cheese is excellent. A cow's milk allergy is more likely to cause symptoms such as hives, chest tightness, or dizziness, while lactose intolerance is not.


For years, researchers have suspected a potential link between casein use and autism spectrum disorders . Parents and caregivers often offer casein-free diet options to children with autism in an attempt to stimulate typical development and reduce challenging behaviors.

Some families report significant behavioral improvements when following a casein-free eating plan, but the evidence is not yet conclusive. As a result, it would be wrong to assume that casein is a cause for concern in children with autism.

Adverse health effects

The popularity of casein supplements for the average adult may be more exaggerated than it is worth. For most people, protein deficiency is rare and supplementation is unnecessary.

Keep in mind that consuming more calories than your body needs, whether from casein-based protein sources or not, can still lead to unhealthy weight gain.

It's also worth noting that a high protein intake from casein or other supplements can be dangerous for some people, especially those with kidney failure. Supplementing with a protein supplement can put dangerous pressure on already weakened kidneys .

Before taking casein or any protein-rich food, it never hurts to consult your doctor.


Despite its muscle-building benefits, casein is not considered a performance-enhancing drug. The natural presence of casein in dairy products allows it to be classified as a food, even when taken as a supplement.

When athletes use casein, there are no associated legal risks, such as those associated with steroids or stimulants.

Get the word of drug information

Casein can have several benefits, especially for babies or adults who exercise with weights. Supplementation with casein can promote muscle growth, but in many cases this is not necessary. If your meal plan includes enough protein from food sources like eggs, meat, shellfish, or soy, chances are you're already getting what you need.

However, for those trying to gain weight or struggling with poor appetite, a casein-based protein supplement can be a great option. Only you (and your healthcare provider) can decide which foods and supplements will best suit your specific needs.

Related Articles
Choosing foods to diet after a heart attack

All cardiovascular specialists agree that a healthy diet is important to reduce the risk of coronary artery disease (CHD) Read more

Different types of hysterectomies.

A hysterectomy is the surgical removal of all or part of a woman's uterus . Hysterectomy is usually done Read more

Esthetician: experience, specialties and training

An esthetician is a person who specializes in cosmetic skin care. Cosmetologists (sometimes called estheticians ) are not medical Read more

Benefits, Side Effects, Dosages, and Interactions.

CBD oil is an extract from Cannabis indica or Cannabis sativa , the same plants that produce marijuana when Read more