Difference Between Whey and Whey Isolate

Medically Reviewed by Jabeen Begum, MD on July 12, 2023
3 min read

Whey powder is commonly used for protein shakes for muscle building or meal replacement.  You may see “whey” or “whey isolate” on the label of your whey powder product. But what’s the difference between the two?

Whey is a group of eight proteins that are found in cow’s milk. These proteins are called:

  • Beta-lactoglobulin
  • Alpha-lactalbumin
  • Glycomacropeptide
  • Immunoglobulins
  • Bovine serum albumin
  • Lactoferrin
  • Lactoperoxidase
  • Lysozyme

Whey is a byproduct of the cheese-making process. Manufacturers use enzymes to curdle cow’s milk, separating out its solid curds and leaving liquid whey. The curds, composed of milk fat, are used to make cheese.

The leftover whey protein is thin and watery. Manufacturers pasteurize this liquid whey to kill bacteria and dry it out to make whey powder. They can then use it to make three different whey products:

  • Concentrate. Whey protein in this form is used in many products, from protein shakes and bars to infant formula. Each has different amounts of lactose (a sugar found in milk) and fat, depending on its intended use.
  • Isolate. Whey is processed to reduce its fat and lactose content, leaving mainly protein. Whey protein isolate may be better for people who have trouble digesting lactose (lactose intolerance). But it’s not for people with milk allergies.
  • Hydrolysate.  When whey protein is hydrolyzed, its protein chains are broken down, which makes it easier to digest. This type of whey is most often used in infant formulas.

Whey protein and whey isolate protein can be beneficial in many ways, including:

  • Building muscles. Protein is essential for building strong muscles. Whey protein, in particular, contains types of amino acids that are great for muscles.
  • Healing properties. If you get hurt or are healing from surgery, whey protein may help your skin heal quicker.
  • Weight gain. Since whey protein aids in muscle growth, it helps you gain weight from the additional mass. Otherwise, whey protein is low in calories. ‌
  • Nutritional supplement. If you’re not getting enough protein in your diet, whey and whey isolate can fill in the gaps.

Amino acids. Whey protein is a complete protein, with nine essential amino acids. Your body makes amino acids, but they’re not the kinds found in whey and whey isolate protein. Amino acids aid in building muscles and creating new immune cells for your body.

Protein. Your body can only process 20-40 grams of protein at a time. If you’re trying to build muscle, you need protein consistently throughout the day. Whey and whey isolate protein supplements are good for this since they’re often premade or easy to mix.

Calories.  You can have whey and whey isolate as part of a healthy diet, but consume them in moderation if you’re trying to lose weight. Read the labels to understand the calories and nutrition in the products you use.

Added sugar and processed ingredients. Many whey and whey isolate products contain added sugar to improve their taste. Check the labels for sugar and for processed ingredients like artificial flavors. Nutrition experts suggest that you limit the amount of processed food you eat, and that includes some whey and whey isolate products.

‌Regulations. Protein supplements aren’t regulated by the FDA for safety and effectiveness.  Whey and whey isolate products might have impurities, fillers, and metal contaminants that aren’t listed on their labels. Look for products that are NSF Certified for Sport or Certified by Informed Choice, as they’ve been independently tested and verified.

Digestion. If you have lactose intolerance, whey isolate is a better choice than whey concentrate. Much of the lactose and sugars are removed from whey isolate during processing. But if you have a dairy allergy, both whey and whey isolate may upset your stomach. In that case, look for plant-based protein instead.

Always talk to your doctor before using a new dietary supplement, especially if you have any health conditions or diet restrictions. Your doctor can help you make an informed decision about what’s best for your health.