These two proteins are both great sources of all the essential amino acids, but they are different in one important aspect—whey is a fast digesting protein and casein is a slow-digesting protein.
Protein Supplementation: Whey vs. Casein
Protein is one of three macro nutrients which are required by the human body for normal
cellular function and growth. Its main task is to establish structure to the cells and tissues
to support everyday activity. Without adequate protein, humans would not be able to
stand, walk, or function at all in any normal capacity. For the athlete, however, protein
goes beyond the sustainability of everyday activity.
Protein ingestion is crucial to the growth, development, and regeneration of skeletal
muscle. Whether you are an athlete seeking larger muscles or one who requires greater
strength, protein plays a major role in obtaining those goals. In an earlier article, I outlined
why protein is so important to the athlete’s diet as well as the most beneficial times to
consume it in order to enhance skeletal muscle protein synthesis and regeneration. This
article’s purpose is not to regurgitate on a topic already discusses, but to delve into the two
most talked about types of protein supplementation, their uses, and the best times to take
- A protein found in milk, that separates from casein (another protein) as a
result of some coagulant being added to the milk. It is the water-soluble part
of this milk protein blend that is quickly absorbed into the tissues. Whey
protein may be used as a dietary supplement to hit daily protein goals, as
well as a tool to enhance skeletal muscle protein synthesis.
- Whey protein is beneficial to the athlete’s diet because it is a readily available
source of protein which will be absorbed by the tissues (i.e. muscle) to
enhance muscle protein synthesis and regeneration to increase muscular
size, power, and/or strength.
- Due to its fast-absorbing properties, whey protein is most beneficial before
and after a workout. It does not provide an abundant amount of protein, nor
are the amino acids it generates withstanding; therefore, other protein
consumption after a workout (i.e. fish, chicken, eggs, beef, etc.) are essential
to furthering muscle protein synthesis to enhance skeletal muscle growth
- The other of the two proteins found in milk. Just like with whey, adding
some coagulant to milk separates these two proteins so that they may be
extracted as separate entities. Casein is the curd-like protein found in milk.
Unlike whey, casein is a slow-digesting protein, due to its gelatinous-like
- Casein takes longer for the cells to absorb, but that delay offers benefits not
found in whey supplementation. As a result of slow digestion, amino acids
(protein) are increased for longer periods of time, causing a reduction in
protein breakdown even after absorption has occurred.
- The long-lasting effects of casein make it a great choice for bedtime protein
consumption. Not only will it help to reach daily protein goals, but it will
reduce the effects of protein catabolism while allowing skeletal muscle
protein synthesis as you sleep.
Neither of these proteins is more superior to the other; however, the time of day consumed
can make all the difference or none at all. Both of these milk proteins offer great benefits
to the enhance muscle protein synthesis and regeneration when used properly, and they
provide even greater effects when coupled with one’s diet. Supplementing with both whey
and casein protein sources has been shown to greatly increase muscle anabolic properties,
increase muscle lean mass, increase muscle strength, decrease fat mass, and increase
All humans need protein to sustain life, but increasing the daily protein need to further
support protein synthesis will enhance size and strength of skeletal muscle. If the goal is to
become better, stronger, faster, at any one specific athletic task, supplementing with both
whey and casein products will be most beneficial, in addition to proper intake of all