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What Is Casein?


Casein is a milk-based protein supplement, derived as a by-product of cheese production, much like its counterpart, whey.

Cow’s milk contains 3.25% protein. Of this, 18% is whey protein, the other 82% is casein protein which contains high levels of the essential amino acids histidine, methionine and phenylalanine. Amino acids are the building blocks of protein and nine of them are referred to as ‘essential amino acids’ because the body cannot produce them on its own. This means we must consume them through dietary intake.

Whey protein is best known as a post-training recovery supplement as it is quickly absorbed. Casein however, is insoluble so it is absorbed slowly, providing a sustained release of amino acids into the bloodstream, sometimes over a duration of a few hours. This makes it ideal for optimising recovery time overnight so many athletes choose to mix casein powder with water and consume it as a pre-bedtime shake.

Other reported benefits include bioactive peptides that can lower blood pressure, plus the binding and transportation of minerals such as calcium and phosphorus, improving their digestibility in the gut.

Casein varies very little to whey in terms of nutritional data, with caloric and protein levels almost identical. As standard though, most casein powders do contain more iron (4% of the RDA, per scoop) and calcium (50% of the RDA, per scoop). This will vary depending on brand, and casein is often more expensive than whey.

Combination blends are available. But when it comes to choosing your protein powder, really you need only identify what the purpose of consuming it is. If you are looking for a post training protein intake, whey is superior for fast recovery. Purchase casein if you are looking to optimise sustained recovery while you catch up on those sleep gains.

Thanks for reading,



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