Optimum Nutrition's Gold Standard Casein Protein is for right after training, you want a fast-acting whey protein to kick-start the recovery process.  But between meals and especially right before bed, a slowly digesting micellar casein shake can provide longer lasting muscle rebuilding support.  That's important, since the majority of muscle rebuilding takes place at night while you're asleep.

Optimum Nutrition's Gold Standard Casein was the industry's first all-micellar casein protein and it's been America's best-selling casein for many years. Casein proteins are pH sensitive and gel in the acidic environment of the stomach. As a result, it can take more than twice as long for caseins to be broken-down into their amino acid subcomponents than whey and other proteins. Because of their unique time-released qualities, caseins are aptly described as anti-catabolic or muscle-protecting proteins.  Micella Casein is the slowest digesting form of casein.  It is seperated from milk through an ultrafilteration process.  One of Micellar Casein's unqiue properties is its ability to gel during digestion so it can release a steady flow of amino acids over several hours.

Optimum Nutrition Casein Protein Powder features:

• 24 grams of micellar casein instantised blend of slow digesting casein based proteins
• Support muscle growth and anti-catabolic prevents muscle wasting
• Perfect slow release and slow digesting protein formula
• Muscle building and fast recovery

Optimum Nutrition Casein Protein Powder contains:

• Rich in highly anti-catabolic micellar casein
• Over 10 grams of BCAAs, glutamine and glutamine precursors per scoop
• Aminogen enhanced
• 24g micellar casein per serve

The formula is instantised to mix easily, and contains patented digestive enzymes to help your body better utilize the 10 grams of essential amino acids provided in each serving. You'll find that casein mixes up rich and creamy like an ice cream shake.

The remaining 80% of the protein in milk is casein.  Often referred to as a “slower acting” or “time released” protein because it is digested and absorbed much more slowly than other proteins, casein proteins are especially useful when taken at bedtime and during other prolonged periods without eating.  Casein proteins are especially useful when taken at bedtime or between meals, so that amino acids can be delivered to muscles for a longer period of time.  It takes longer to digest and empty from the stomach compared to other proteins.