Right after a tough workout many turn to a fast-acting protein, such as whey, to deliver essential nutrients to your muscles quickly and initiate the recovery process. But at other times you don’t want such a sudden rush of amino acids, and instead need a slow and sustained release to keep your muscles well fed – like when you’re getting your all-important eight hours of sleep. That’s when casein protein comes into its own. For all the info on casein, we spoke to Adam Feit of PrecisionNutrition.

What is casein protein?

Casein is one of the two forms of proteins that come from dairy, whey being the other one.

How is casein different from whey?

Whey protein has a higher and quicker rate of absorption than casein. Though both are among the richest sources of essential amino acids, which are important for muscle growth, casein is more gel-forming in the gut than whey. This means it’s digested and absorbed more slowly, releasing its nutrients into the bloodstream over time rather than all at once.

When should you take it?

You can have a casein-based protein any time if it helps you fulfil your protein needs, whether the goal is improved health, fat loss or muscle gain. But if maximal muscle gain is the goal, then before bed might be an extra beneficial time to have casein protein, either via powder, Greek yogurt or cottage cheese.

Are there any possible negatives to using casein powder?

As stated, casein protein has the tendency to become more “gel-like” than whey so drinking too much of it around exercise could cause some gastrointestinal discomfort and distress. If you want to take a protein supplement close to high-intensity activity, consider a whey protein alternative instead.

What should you look for when choosing between different brands of casein powder?

The major litmus test for any type of supplement is the purity and safety of the ingredients themselves. Consumers should ensure that their purchase has been tested by a third party such as NSF, Informed Choice or Consumer Lab.

Also, try to get a casein protein that is mostly just protein, with relatively small amounts of carbs and fats. Some supplement companies add fillers, which can add unnecessary calories to the overall total. Consider experimenting with protein blends that contain a mixture of whey, casein and other proteins, such as egg.