Ask the Experts: What's the Difference Between Whey and Casein Protein?

Protein Shake

Q:  What is the difference between whey and casein protein?

A: The two types of protein for athletes are whey and casein, and although they are both derived from cow's milk, they provide different benefits and should be consumed differently.


Whey is a high-quality protein that makes up 20 percent of the protein found in milk. It's easily digested and absorbed, so you should consume it within 30 minutes after a workout to supply your muscles with amino acids.


Casein makes up 80 percent of the protein in cow milk, but it gets digested much slower than whey protein, thus reducing muscle breakdown throughout the day and helping to sustain the muscle-building effects of weight training. It's best to consume casein throughout the day or before bedtime for an additional muscle-building effect.

Remember that protein powder and other protein supplements should be used to supplement your diet, not as a substitute for whole food protein options such as lean meat, fish, nuts, milk and eggs.


Andy Haley Andy Haley - Andy Haley is the Performance Director at STACK. A certified strength and conditioning specialist (CSCS), he received his bachelor’s degree in exercise science from Miami University...
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