Originally posted on the Academy of Nutrition and Dietetics: Sports, Cardiovascular, and Wellness blog

For many people consuming a post workout protein shake has become an after gym ritual. Still there’s some controversy about what type of protein to take and when to drink your shake. The two most common types of shakes are casein (a slow acting protein typically found in mammalian milk) and whey (a fast acting protein that is a by-product of dairy production like cheese). Fortunately a Danish study at Institute of Sports Medicine Copenhagen has provided some interesting information.

In the study 17 men were split up into 3 groups a control group that got supplemented with water, a group administered 20 g whey, and another that received 20 g of casein. The men in the study were asked to do 10 sets of 8 reps on a leg extension machine and immediately supplemented with the control or protein dosage after the last set. The results showed that in the first 3 hours after intake the muscle protein production was higher in the whey group than the casein group and in the last 3 hours it was higher in the casein group. Over the course of the 6 hours the total muscle group was about the same.[1]

A potential inference someone can take from this study is that if they’re looking to maximize muscle protein synthesis after a workout, supplementation of either whey and casein simultaneously after a workout or supplementing whey in two 3 hour intervals post workout will be effective methods in ensuring the highest possible levels of cellular muscle protein synthesis.

References

Reitelseder, S., Agergaard, J., Doessing, S., Helmark, I., Lund, P., Kristensen, N., . . . Holm, L. (2010). Whey and casein labeled with L-[1-13C]leucine and muscle protein synthesis: Effect of resistance exercise and protein ingestion. AJP: Endocrinology and Metabolism.