In the health and fitness community, whey protein tends to get all the attention. Its fast-absorbing, lean protein that’s designed for people who are looking to build muscle and lose fat and its many flavor options make it easy to incorporate into your daily meal plan.

That said, whey protein is only part of the equation. Casein protein, the lesser-known type of supplemental protein, has similar advantages to whey. The main difference—and appeal—of casein, however, is its slow-digesting and long-lasting protein.

What is Casein Protein?

Like whey protein, casein protein is a component of milk that is a by-product of the cheese-making process. Roughly 80 percent of cow’s milk protein is casein. Casein is also an abundant source of the branched-chain amino acids (BCAAs) valine, leucine, and isoleucine.

BCAAs are essential amino acids, meaning they must be derived from diets since our bodies can’t produce them. There are twenty amino acids in total, nine of which are essential. Plant-based protein provides some amino acids, but animal products, including casein, provide a complete amino acid profile.

Amino acids are the basic building blocks of protein that play a role in energy production for a variety of processes in the body, including protein synthesis. This is the main process through which we build muscle, so the full spectrum of essential and non-essential amino acids is needed for maximum muscle growth and minimal muscle loss, as well as peak athletic performance.

The Benefits of Casein Protein:

  1. Muscle-Sparing: When your body needs protein for energy or growth, it will break down existing muscle mass to get the amino acids it needs. This is especially true following strenuous exercise, which is why high-quality protein is vital following a workout. Casein is an “anti-catabolic” protein, meaning its amino acids are readily available for use and minimize the breakdown process.


  1. Slow-Digestion: Casein protein is quickly absorbed into the bloodstream, but it digests slowly. This allows the amino acids to remain available to your body for longer periods of time, which it can use for muscle growth and recovery.


  1. Overnight Recovery: Your body uses sleep to repair itself. Casein protein provides a steady flow of amino acids for several hours, making it an exceptional snack before bed. While you sleep, your body has ample opportunity to use those amino acids to aid in muscle repair.


  1. Meal-replacement: Similar to its overnight use, casein protein makes a great meal replacement or between-meal snack. During long periods without protein, casein’s slow digestion keeps your body from breaking down muscle to meet its needs.


  1. Appetite Control: Even for a casual dieter, casein protein is still beneficial for appetite suppression and curbing cravings. Because it stays in your bloodstream longer, casein modulates your blood sugar and keeps you satiated between meals—two major obstacles in dieting—and keeps you on track. Casein is also low in calories and almost pure protein.

Casein Protein Nutrition and Use

Casein protein powder nutrition varies, but in general, casein protein powder contains:

  • 120 calories
  • 23 grams protein
  • 1 gram fat
  • 1 gram sugar
  • 450 milligrams calcium

The optimal dosage of casein protein powder is determined by your activity level, weight, and goals, but the general guidelines are:

  • 68-1 gram protein per pound of body weight for highly-active individuals
  • 45-0.68 gram protein per pound of body weight for moderately-active individuals or those looking to lose weight
  • 36 gram per pound of body weight for low activity levels and weight maintenance


Casein Protein vs. Whey Protein

Both casein and whey are derived from milk, help build and repair muscle tissue, and provide additional protein and a full amino acid profile, but their behavior in the body is the most significant difference between the two.

The popularity of whey protein as a post-workout supplement is mainly due to its fast-acting protein. It causes an amino acid spike in the blood, which makes it quickly available for protein synthesis. Our bodies can only absorb so much at once though, so any unused protein is excreted. Conversely, the fast-acting nature of whey protein also means its amino acids aren’t available for long periods of time.

Casein, on the other hand, digests slowly and remains available for several hours. Because of this, casein has less of an impact on protein synthesis, but more effect on muscle tissue preservation and repair.

When timed appropriately, these two differing protein sources allow your muscles the immediate protein for growth and repair, as well as the long-lasting protein for preservation and recovery.

Supplement Timing

Due to the differences between casein and whey protein, the timing of their supplementation is important.

sports watch

Whey protein is fast-acting, so it’s needed before and after workouts to supply muscle tissue with the protein it needs for growth. Whey protein is also a good choice in the morning since your body is in a fasted state and your muscles need readily-available protein to prevent muscle breakdown.

Casein digests slowly, so it’s best used before bed to preserve muscle tissue and aid in repair, as well as between meals to curb appetite and cravings.

If used at appropriate times, both casein and whey protein are part of a comprehensive supplement plan for muscle building and preservation.

Lactose-Intolerance and Milk Allergies

Lactose-intolerance is a condition in which the body can’t properly digest the sugars in milk (lactose), resulting in such digestive issues as bloating, abdominal cramps, and diarrhea. Milk allergies can be triggered by one of the twenty known allergens in milk and may result in anything from mild allergic reactions to full anaphylaxis. Both of these conditions are more prominent with cow’s milk, as well as other milk-derived products, such as casein protein.

cows milk glass

For individuals with these conditions, the milk produced by goats is less likely to cause a reaction because it is similar to human breast milk and contains fewer allergens. Casein protein made from goat’s milk will offer all of the same benefits of cow’s milk casein, with far less risk.

Bottom Line

Ultimately, both casein and whey protein will provide your body with the complete protein it needs. While whey protein is designed for fast muscle growth from near-immediate absorption, casein protein’s slow digestion makes it useful for preserving muscle over long periods of fasting or in between meals.

The biggest advantage of casein protein is its ability to preserve and repair muscle tissue overnight, while your body is already working to recover. To give your body the best nutrition for peak performance, casein protein is a highly-beneficial addition to your supplement routine.