Casein Before Bed: The Science Explained

Protein: The essential building blocks (Amino Acids) for stimulating muscle growth (MPS: Muscle Protein Synthesis).

Casein is a slow-digesting dairy protein that people often take as a supplement. It releases amino acids slowly, so people often take it before bed to help with recovery and reduce muscle breakdown while they sleep. Several studies have shown it helps boost muscle growth.

Casein can be found naturally in Cottage Cheese, yoghurt and Milk. Casein is a protein found in mammalian milk, making up roughly 80% of the protein found in cows’ milk (the remaining 20% consists of whey) and it is more slowly digested than whey.

Casein’s slower rate of digestion is primarily related to its structure since its coagulation in the stomach slows the rate of gastric emptying. Indeed, this slower rate of digestion of casein, compared with the rapid digestion of whey results in a more sustained elevation in blood amino acid levels and a greater inhibition of protein breakdown.

Given the slowly digesting nature of casein, its ingestion prior to sleep has become a popular strategy for athletes looking to minimise muscle loss and enhance muscle gain. Both short and longer-term studies examining the efficacy of this are fraught with limitations in that the specific timing of ingestion of casein cannot be concluded. Nonetheless, the ingestion of casein prior to bed does seem to be a good strategy to incorporate more protein into a diet in which it is lacking.

In the absence of sufficient data, when looking at things theoretically, it does not seem likely that casein ingestion before bed would be advantageous for someone who is getting sufficient amounts of high quality protein, distributed throughout the day; strategies that most conscientious athletes would already be doing.

As such, our recommendations to individuals looking to optimise rates of muscle gain, adaptation or preserve muscle mass are as follows:

  • Consume sufficient quantities of quality protein relevant to your goal.

  • Spread this daily protein intake evenly across 4-6 meals every 3-4 hours.

  • Once these factors are consistently in place, feel free to experiment with pre-bed protein feeding. If you do not feel/see a benefit to this, disregard this protocol and carry on nailing the stuff that does matter.


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