Is Casein Bad For You?

Is Casein Bad For You?

Is Casein Bad For You?

By this time in your search for answers, you are undoubtedly aware that very few nutrients are as critical to your overall health and wellbeing as protein and that there are several ways to ensure your body gets it.

At the highest level of simplification, the protein you consume is behind most work performed by the cells that make up all the structures, functions, and governance of our body's soft tissues and critical organs.

At AGN Roots, we are dairy people with a unique affinity for the health and wellness of people, animals, and the planet. We supply a single product representing what dairy protein can be if all things considered; decency is the backstop at every step of our product's sourcing, manufacturing, and packaging. We provide the world's best grass-fed whey and thus do not hold bias regarding other milk proteins or casein powder in general.

In this article we will answer the following questions about casein protein -

  • What is Casein Protein?
  • What are the Benefits of Casein?
  • What are the Differences between Casein and Whey Protein?
  • Is Casein Protein Good for Weight Loss?
  • Is Casein Bad for You?
  • Does Casein Have Lactose?

Let's take a deep dive into these questions and more so that you can make an informed decision about your protein supplementation.

What is Casein?

About 80% of all of the protein in cow's milk is casein. The remaining 20% is whey. When milk's natural emulsion breaks down via applied heat and culture (enzymes) at the beginning of the cheese-making process, curds and whey become very distinct phases of solids and liquid.

The solid curds that float on top of the liquid phase consist of milk fat surrounded by a sticky sheath known as casein micelles. In nature, casein exists as a molecule that has a hydrophilic head and hydrophobic tail. This inherent makeup of the casein molecule gives breath to what the supplement industry calls Micellar Casein.

What is a Casein Micelle?

A Micelle is another word for a structure or a cluster that resembles a sphere in shape. When casein is free to move in water, a natural clustering forms when multiple casein molecules orient themselves such that their water-loving heads are in contact with the water while their water-fearing tails all hang with each other on the inside.

Four types of casein protein exist.  Each type differs solely based on the number of phosphate molecules for each mole of casein. These subtypes are as follows:

  • aS1-Casein
  • aS2-Casein
  • b-Casein
  • k-Casein

A Casein Micelle ranges in diameter but falls within 20-300 microns [8].  

Learn More: A2 Milk Explained

Is Casein a Vegan Protein?

Casein is a reduction of animal milk and thus does not belong within a strict vegan diet. Casein protein like whey protein is a source of nutrients often consumed by lacto-vegetarians.   

Is Casein a Complete Protein?

Yes, like whey protein, casein is a complete protein. Later in this article is a side-by-side amino acid comparison that leaves most industry professionals thinking that the digestion rate differences between whey and casein may be more critical than the amino acid composition of the protein themselves.

What Role Does Casein Play in Nature?

A two-month-old calf will drink an average of eight liters of milk per day. In less than 15 months, this cow will tip the scale at ~ 2,500 lbs. Likewise, human babies will have tripled their body weight in the first six months by drinking milk. So the purpose of milk in nature is truly in service of growth & development.

But what is it about milk that promotes this type of growth? Most athletes are under the impression that the whey protein in milk contributes to the most substantial tissue development, when in fact, cow milk protein is nearly 80% casein and only 20% Whey.

The majority of the growth attributed to milk protein comes from casein. This begs the question, why does whey protein dominate the market while casein struggles to gain traction in terms of popularity?

Why Casein Protein Powders are Marketed Less?

The most straightforward answer is money; making casein powder doesn't allow for the typical cost recovery that comes with the production and sales of other dairy products like cheese manufacturing that making whey protein does.

Extracting micellar casein protein can only occur at the cheese-making process's sacrifice as it involves removing protein directly from the milk. Without assistance from casein proteins, curds cannot form.

On the other hand, whey protein is separated from the curds (Casein sheath around fat) and drained as part of the cheese manufacturing process, leaving the cheese unaffected. The ability to utilize 100% of the milk with no waste is where the confusion often marginalizes whey as a "by-product" of cheese manufacturing as if this is a bad thing?

Why is Casein Protein "Slower Digesting?"

The supplement industry content marketers out there all sing the same tune in characterizing casein protein. "Casein protein is slow digesting"; well, we hope to shed some light on the specific details and explain why this is only partly true.

Casein is incredibly sticky, and the consumption of a casein protein shake transforms the casein from a liquid to a sticky solid in the stomach, increasing the time it takes to digest.

Contrary to all supplement website hacks, molecularly, casein is very easily broken down and digested. It is "slower-digesting" because of its gel-forming properties, which slows down casein's intestinal motility purely from a mechanical nature.

It is not commonly known, but to drive the point home as to how slow casein may move through your digestive tract, the primary ingredient in white grade-school glue is casein!

As for performance athletes, we need slow amino acid release as numerous studies have proven this pattern to be the most powerful at promoting an anti-catabolic environment for muscle growth. Put differently, regularly consuming casein makes it difficult for your body to reach a fasting state as the slow-moving casein is synonymous with nutrition on a drip. 

Whey vs. Casein - How it's Made

How is Whey Protein Produced?

  1. Milk – Collected from cows
  2. Standardization – The milk is pasteurized
  3. Culture & Coagulation – Bacteria used to trigger coagulation
  4. Cutting – Liquid whey & curds are separated
  5. Draining – whey is drained, leaving the solids behind (curds)
  6. Filtration whey is filtered & concentrated to desired protein density
  7. Dehydration  The concentrated whey is spray dried to a desired moisture content

How is Casein Protein Produced?

  1. Milk – Collected from Cows
  2. Standardization – The milk is pasteurized
  3. Coagulation - Rennet Method or Acid Method (see below)
  4. Drained - Whey & water are drained
  5. Washed - Casein solids are rinsed to remove whey, lactose, and salts
  6. Dehydrated - Spray Dried or Rolled

Casein Rennet Method – Enzymatic precipitation (curds and whey by use of chymosin)

Casein Acid Method Acidifying milk via pH manipulation (pH 4.6 – 4.7) via addition of hydrochloric acid (HCl) or sulphuric acid (H2SO4).

Is Casein Bad For You?

Undoubtedly a charged proposition such as the question "Is casein bad for you?" is deserving of the "it depends" pencil whipping.

There are a few risks and potential side effects associated with ingesting casein. These risks are not germane to casein consumption solely but somewhat similar to the risks associated with consuming many foods or drinks, particularly dairy.

Risks resulting in adverse reactions from casein exposure most likely stem from the following conditions:

  • Lactose Sensitivities
  • Irritable Bowel Syndrome (IBS)
  • Inflammatory Bowel Disease (IBD)
  • Leaky Gut (i.e. Increased Intestinal Permeability)
  • Gut Bacteria Imbalance
  • Protein or Milk Allergy
  • Low Quality Products or Supplements 

The answer to this question is no; casein is not bad for you. Relative to whey protein or milk protein, the consumption of casein does not create additional risk. Below are a few common myths out there we can dispel today.

Learn More: Dairy Protein and Bioavailability (Digestive Health)
Learn More: Side Effects of Dairy Proteins

Common Casein Fallacies

Does Drinking Milk Increase Mucus Production? 

No - This notion regardless of it's wide spread belief has yet to be scientifically proven to any degree worth getting excited about. Websites that use this tired myth as a way to bash milk or casein protein as a beneficial supplement are unfashionable at best [7].

Does Casein Strain your Digestive System?

No - If this were the case, consuming liquid milk would also "strain" the digestive system, and this is not the case. Ruminant animals naturally secrete an enzyme called chymosin, the principal catalyst responsible for curdling milk in the stomach.

The purpose of chymosin in dairy cows, especially when very young, is to prolong the amount of time the casein curd is in contact with the intestinal wall. The increase in contact time ensures the optimal transmission of nutrients and increased satiety. 

Does Too Much Protein Destroy Your Liver?

This fake news sprouted via the American Heart Association back in early 2000 when hypothesizing that high protein diets may have damaging impacts on liver function. The connection naturally grew into a talking points by liver health supplements that are to this day share shelf space with powdered protein products. The idea that the liver experiences high stress levels to metabolize a high protein diet fails to align with any current scientific evidence or credible study [9].

Casein Vs. Whey Protein: What's the Difference?

To best compare the amino acid profiles between whey and casein powders, we purchased samples of both whey & casein from a known origin (the same farm) in Wisconsin and sent them off to be analyzed. 

The findings are that both casein and whey are complete proteins made up of the same amino acids, albeit in slightly different compositional densities. The results are below, and the amino acid units are in grams / 100 grams of the protein powder.

 Amino Acid More  Whey Protein (g) Casein Protein (g)
Aspartic Acid Whey 10.1 6.3
Threonine Whey  6.8 3.6
Serine Casein 4.2 4.4
Glutamic Acid Casein  13.8 16.9
Glycine Whey 1.7 1.5
Alanine Whey 5.2 2.7
Valine* Whey 5.4 5.0
Isoleucine* Whey 6.0 4.0
Leucine* Whey 9.0 7.9
Tyrosine Casein 2.2 4.2
Phenylalanine Casein 2.6 3.6
Histidine Casein 1.1 3.9
Lysine Whey 7.8 6.5
Arginine Casein 1.8 3.2
Proline Whey 5.6 7.9
Cystine Whey 2.1 0.5
Methionine Casein 1.8 2.3
Tryptophan Casein 0.8 1.4


Does Whey or Casein Contain Greater BCAAs?

The "*" amino acids in the above chart illustrate clearly that whey protein does contain a higher concertation of branched chain Amino Acids than casein.

What is Better for Building Muscles, Casein or Whey?

Scenario #1 - Single Serving Per Day

If 25 grams of whey protein or casein protein is consumed simultaneously over two months, the casein protein provides more significant muscle-growth potential.

Unlike whey protein, casein protein supplementation increases protein synthesis for a prolonged duration, and thus 100% of the protein is working for the goal of muscle building.  However, the consumption of whey protein leads to a short-lived spike in the plasma appearance of amino acids, a substantial portion of which is oxidized and burned as fuel.

Scenario #2 - Several Servings Spaced Equally Apart Per Day

When the consumption of whey protein occurs every few hours, and the fast transient nature of its composition over multiple sittings sustains the peak plasma appearance levels of amino acids, whey protein then becomes the muscle mass favorite. 

Is Casein or Whey Better for Improving Body Composition?

Research shows the casein consumption over whey protein in conjunction with resistance training leads to more significant strength gains and improved body composition impacts.

The study made up vastly overweight police officers compares whey and casein effects when the consumption per day is 1.5 grams of protein per kg of body weight two times daily 10 hours apart for 12 weeks [10].

Is Casein or Whey More Expensive More Expensive?

As stated above, casein production does not allow for the cost recovery element that whey production allows for.  When a producer sells whey protein, they also sell cheese and butter. In contrast, if you are after a casein supplement from an amazing source like our farms in southeast Ireland, the cost of extracting casein will need to cover the loss in potential cheese and butter sales. This makes Casein protein substantially more expensive when side by side with whey. 

Does Casein or Whey Have Better Macro-Nutrients?

When the conversation becomes less about the muscle-building benefits of dairy protein and more about the macro-nutrition, hands-down, there is no comparison whey protein is the clear winner. Unlike even the best casein proteins available, whey protein like AGN Roots Grass-Fed Whey contains the following macro-nutrients that make the matter of its grass-fed origin standout.

A Truly Grass-Fed Whey Protein Contains - 

  • Beta-Lactoglobulin
  • Alpha-Lactalbumin
  • Immunoglobulins
  • Bovine Serum Albumin
  • Lactoferrin
  • Lysozyme
Whey Vs Casein Fractions - Composition Wheel

Learn More: Protein Fractions Explained

Is Casein Protein Good For You?

There are a number of benefits associated with supplementing with casein or eating casein as a part of your diet. Here are the facts and main benefits summarized -

  • Antimutagenic Properties - Casein protein along with the peptides derived from casein contain antimutagenic properties that demonstrate anticancer potential [3, 4, 5].
  • Enhanced Micro Nutrition - Casein tends to carry greater concentrations of calcium and other minerals and vitamins. 
  • Strength Athletes - Casein is beneficial for strength-based athletes
  • Weight Loss - Casein is the preferred weight loss protein

What is Casein Protein Good For?

Is Casein Good for Weight Loss?

Yes, casein is the perfect supplement if your goal is to give yourself more time between snacks or meals. Making a protein shake with casein, fresh fruit, or greens is a direct path to weight loss.

The upside is losing weight while not feeling like you are starving yourself. The downside is the intentional feeling of a full-belly or bloated longer as the casein takes its time working through your system.

In terms of a meal replacement solution, this is it. The weight loss benefit isn't from the intake of casein protein calories; instead, it's indirectly due to what won't make it to your plate due to feeling satisfied (full stomach) for longer.  Choosing to utilize casein for a meal replacement essentially equates to causing a net reduction in calories consumed per day.

Is Casein Good for Muscle Growth?

Yes, if one of your goals is to build lean muscle mass, let's go back to Mother Nature's purpose of milk which by macro, is predominantly casein protein. Milk is the fuel that allows infants and calves to double in size in no time; 81%-82 % of this protein is casein, while < 20% is whey.

Casein allows you to grow while sleeping. Filling up on a 2,000 calorie casein shake and passing out will certainly enable even the hardest-gaining ectomorphs a chance at packing on pounds before the next sports season begins.

Casein Studies Show Blood Pressure Benefits

A study conducted in 2014 found a 3% improvement in diastolic blood pressure as a sample of just shy of 200 obese adolescents supplemented with casein protein. The results indicate that a high intake of casein protein positively impacts the diastolic blood pressure of adolescents if overweight [11].

Does "Grass-Fed" Casein" Matter?

The masses have become increasingly aware of the importance of animal welfare and treatment for both the meat and dairy industry.

Not only is there a push to fight for animals to have a reasonable and pleasant quality of life, but our community of health enthusiasts is also growing more mindful around sourcing nutrition.

In the dairy industry, Truly grass-fed is synonymous with the highest animal welfare standards and strict standards and operational best practices; thus, it matters. Like all "grass-fed" protein claims, the naked claim means little unless a globally recognized accreditation verifies it.

From a compositional point of view, a casein protein that is verified grass-fed will contain a better amino acid profile and thus have a higher branched-chain amino acid concentration.

In terms of all the fantastic macro-nutrients list above that come from a genuinely grass-fed whey protein no, casein will still not contain these nutrients; the incremental premium for a grass-fed vs. non-grass-fed casein deserves attention and justification.

When is Casein Bad for You?

In the last few years, casein quality has increased due to the global pandemic and the subsequent decline in demand for milk. Organic and grass-fed operations within the United States sell a portion of their milk as conventional to ensure they can move it. As the highest quality milk moves first, thus the threshold for milk designated for disposal (~40 million gallons/year) provides a quality of milk that many brands would never see.

Before the pandemic, hundreds of pop-up supplement brands sprouting up by the day in the United States, discovering a surplus of Concentrated Animal Feeding Operation (CAFO) milk available for as cheap as $1 per 100 lbs, entered the marketing scene and introduced their "native" dairy proteins.

Today, due to million-dollar marketing campaigns, consumers believe "native" whey or casein to be beneficial and value-added to their nutrition. All while conventionally processed, whey has become a "byproduct" of cheese making. 

This relatively new access to inventory paired with more and more processing plants offering the "native" process enables the abuse to continue. The "native" method for extracting whey and casein represents the worst of the worst in preserving nutrients in the milk but does allow milk of the lowest quality to be salvaged for powder and marketed by any means necessary under the loose regulation of the Dietary Supplement Health and Education Act (DHSEA).

Dairy products originating from CAFOs, which make up roughly 96% of the United States dairy production, may easily contain contaminants such as nitrogen, phosphorous, heavy metals., antibiotics, particulate matter, and a slue of pathogens. Unless the product is tested and verified by a 3rd party accreditation, we recommend another whey/casein.

You can not go wrong with sourcing protein such as Grass-Fed Whey The Right Way! Any questions, please don't hesitate to contact us at

Learn More: What are CAFOs?
Learn More: What is "Native" Protein (Whey or Casein)?

[1] Pendick, Daniel. “How Much Protein Do You Need Every Day?Harvard Health, 21 June 2019,
[2] Haug, Anna et al. “Bovine milk in human nutrition--a review.” Lipids in health and disease vol. 6 25. 25 Sep. 2007, doi:10.1186/1476-511X-6-25
[3] Parodi, P W. “A role for milk proteins and their peptides in cancer prevention.” Current pharmaceutical design vol. 13,8 (2007): 813-28. doi:10.2174/138161207780363059
[4] Pettersson, Jenny et al. “alpha-Lactalbumin species variation, HAMLET formation, and tumor cell death.” Biochemical and biophysical research communications vol. 345,1 (2006): 260-70. doi:10.1016/j.bbrc.2006.04.081
[5] Raja, R Balaji, and Kantha D Arunachalam. “Anti-genotoxic potential of casein phosphopeptides (CPPs): a class of fermented milk peptides against low background radiation and prevention of cancer in radiation workers.” Toxicology and industrial health vol. 27,10 (2011): 867-72. doi:10.1177/0748233711407244
[7] Thiara, Gurkaran, and Ran D Goldman. “Milk consumption and mucus production in children with asthma.” Canadian family physician Medecin de famille canadien vol. 58,2 (2012): 165-6.
[8] Rifky, Mohammad. “FUNDAMENTALS of Dairy CHEMISTRY 3 RD EDITION.” Edited by Noble P. Wong,, Aspen Publishers, Inc. Gaithersburg, Maryland 1999, 1988, 
[9] Hoffman, Jay R, and Michael J Falvo. “Protein - Which is Best?.” Journal of sports science & medicine vol. 3,3 118-30. 1 Sep. 2004
[10] Demling, R H, and L DeSanti. “Effect of a hypocaloric diet, increased protein intake and resistance training on lean mass gains and fat mass loss in overweight police officers.” Annals of nutrition & metabolism vol. 44,1 (2000): 21-9. doi:10.1159/000012817
[11] Arnberg, Karina et al. “Casein improves brachial and central aortic diastolic blood pressure in overweight adolescents: a randomised, controlled trial.” Journal of nutritional science vol. 2 e43. 2 Jan. 2014, doi:10.1017/jns.2013.29
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