• Connor Meyler

Whey Vs Casein

Updated: Jul 6, 2019

Walk into a supplement shop you will come across at least five to ten different tubs of protein all claiming to be the best there is. Truth be told, they all have their pros and cons.

Here are two types of protein most commonly found in supplement shops and the pros and cons of each. But first, how are they made?

Milk is made up of 80% casein protein and 20% whey protein. When milk is curdled and strained during the cheese making process, whey becomes the liquid by-product. The remaining curds of casein can be washed and dried to create a protein powder or added to dairy products, such as cottage cheese.

Whey protein


  • Complete protein source with all the essential amino acids.

  • Fast digesting. Great for per-workout nutrition to stimulate muscle recovery.

  • EAAs are associated with better muscle protein synthesis (MPS). Research shows that whey is better than other types of protein, including other complete proteins like casein, at stimulating muscle growth and repair following a workout.

  • Whey is one of the richest sources of the amino acid cysteine. Cysteine boosts levels of glutathione, one of the strongest antioxidants in our cells. Glutathione’s main function is to protect our cells from damage caused by free radicals. It also contains a number of active proteins called immunoglobulins that boost your immune system.

  • Mixes and tastes better than casein protein powder.


  • Whey is a by-product of milk and therefore contains lactose. If you’re lactose intolerant, then whey protein may not be the best source for you.

  • Whey can be highly processed. Unfortunately, since it’s highly processed, whey often contains undesirable ingredients like soybean oil, vegetable oils, artificial sweeteners (aspartame, acesulfame), and artificial flavours.

Casein protein


  • Complete protein source with all the essential amino acids.

  • Slow digesting protein may result in better uptake by the cells by allowing a steadier and more efficient release of amino acids. It reduces protein breakdown within the body due to its slow digestion rate and sustained supply of amino acids to muscle cells.

  • Casein is an excellent protein source to promote satiety.

  • Casein contains less lactose than whey protein.


  • Leucine is an amino acid that kick starts muscle protein synthesis and other protein supplements contains more than casein.

  • Casein gels as it comes into contact with stomach acid and this slow digestion rate can make it difficult for some to digest.

  • Casein protein powder is generally more expensive than whey.

Bottom line

  • Casein and whey protein are both derived from milk.

  • They differ in digestion times.

  • Both contain different bioactive compounds that may boost your immune system and offer other benefits.

  • Several independent research reviews have concluded that neither whey nor casein holds a clear advantage over the other when it comes to weight loss and weight maintenance.

  • Choosing one over the other won’t necessarily bestow better results in the gym. Above all, remember that your total daily intake of protein matters most.

  • While casein and whey have their differences, they each play important roles in your body and provide numerous health benefits.

I always recommend that my clients get their nutrients from food as opposed to supplements. However, if their diet is lacking in essential nutrients, then supplementing with whey or casein protein is a convenient way to boost protein intake and choosing between the two usually comes down to personal preference.

Capel fitness Is situated on the -1 floor of The Capel Building, Capel St, Dublin 7. 
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