Casein offers the same benefits as any other protein supplement — an easy way to increase your protein intake. The benefits of a higher protein intake include limiting muscle loss during periods of caloric restriction, slowing down muscle loss due to aging (sarcopenia), and supporting muscle growth with resistance training.
Casein contains all the essential amino acids. It also contains leucine (although less leucine than whey protein) which helps stimulate muscle protein synthesis (MPS).[1] Casein ingestion will result in a slow release of amino acids into the bloodstream. This can be useful as a nighttime drink to ensure ongoing MPS while asleep. Following casein intake, the amino acid concentration slowly rises, peaking at about 7 hours post intake (compared to whey protein which peaks at 1-3 hours).[2]
Casein may also increase satiety, helping you to stay fuller for longer compared to other types of protein, since it is slower to digest. This effect is not universal[3] but is especially noted in the long term when casein is used regularly over a period of weeks.[4]
Other possible benefits — including lowering glucose in diabetics, lowering blood pressure, and lowering lipids — remain uncertain.[5] Casein also does not have any direct benefit in terms of fat loss, although it might help with satiety.[6]