What Is Casein Protein?

Casein Protein

Casein Protein


Casein is a slow-digesting dairy protein that makes up about 80% of the protein in cow’s milk. It is often taken as a supplement by athletes and bodybuilders.


  • During digestion, casein forms a gel in the stomach, slowing down the absorption of amino acids into the bloodstream.
  • This results in a sustained, gradual release of amino acids that can last for hours.
  • Casein is high in glutamine, an amino acid important for muscle protein synthesis.
  • It is commonly taken before bed to provide a steady supply of amino acids as you sleep and fast.


  • Casein protein powder – extracted and isolated casein protein
  • Cottage cheese – contains mostly casein along with whey
  • Milk – approximately 80% casein, 20% whey


  • Whey protein – fast digesting dairy protein
  • Amino acids – building blocks of protein
  • Myoprotein synthesis – building of new muscle tissue


  • When should I take casein protein? Bedtime is ideal, but it can be taken any time a slow release of amino acids is desired.
  • Is casein better than whey? Not better or worse, just different release rates suited to different purposes.


  • Whey protein – though both dairy proteins, whey digests rapidly while casein digests slowly.
  • Milk protein – contains a mix of casein and whey proteins.
75 / 100

Thank you for reading this post, don't forget to subscribe to our free newsletter