Casein vs Whey Protein: What's the Difference?

Whey and casein both come from milk, but they behave quite differently. Here's how to tell them apart and when each one makes sense.

Whey: fast-digesting

Whey protein is absorbed relatively quickly, which is why it's such a popular choice around training and any time you want a quick, easy shake. It mixes thin and comes in a huge range of flavours.

Casein: slow-digesting

Casein digests more slowly, releasing its amino acids over a longer period. That's why many people reach for it before bed or between meals when they want a longer-lasting, thicker shake.

Which should you choose?

For an everyday, all-purpose protein, whey is the simple pick. If you specifically want something for the evening or a long gap between meals, casein is worth adding. Some people keep both and use each when it suits.

Find both in our protein powder range. Fast, tracked Mon–Fri UK delivery on every order.

A quick note

This article is general information, not medical or nutritional advice. Food supplements are not a substitute for a varied, balanced diet and a healthy lifestyle, and should not be used to prevent or treat any illness. Always read the product label, do your own research, and speak to a qualified doctor, pharmacist or registered nutritionist before starting a new supplement — especially if you are pregnant, breastfeeding, under 18, taking medication or managing a health condition.