Difference Between Whey and Whey Isolate

Medically Reviewed by Jabeen Begum, MD on June 26, 2024
6 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. 

Whey is used to make three different 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. 

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.

The different types are sometimes called WPC (concentrate), WPI (isolate), and WPH (hydrolysate).

Whey protein isolate vs. concentrate: Which is better for lactose intolerance?

Whey isolate has less lactose, which makes it a better choice if you're lactose-intolerant. If you have a milk allergy, though, you should avoid whey products. 

Whey protein and whey isolate protein both 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. Because 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.

Whey concentrate may be a better choice if you're looking for something to help you recover faster from workouts. It has more of the ingredients you'd find in whole milk. 

One large analysis of several studies suggested that whey protein concentrate was better for reducing fat mass -- the fat stored just under your skin and around your organs -- than other forms of whey protein. However, women and those assigned female at birth weren't well-represented in the studies, and more research is needed. 

Pros of whey and whey isolate

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 process only 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 useful because they’re often premade or easy to mix.

Whey isolate and whey concentrate have some of same downsides, although there are subtle differences. 

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. Whey concentrate generally has more fat, carbohydrates, and calories than whey isolate.

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. 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.

Cost. Whey isolate is more expensive than whey concentrate. That's because manufacturers take extra steps to reduce fat and lactose.

Nutritional deficiencies: Whey protein is intended to be a supplement to your diet. Experts recommend that you get your protein from whole foods instead of supplements. Good sources of protein include: 

  • Nuts and seeds
  • Low-fat dairy products such as yogurt, cheese, and milk
  • Beans and lentils
  • Fish
  • Poultry
  • Eggs
  • Lean meat

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.

The benefits of whey protein isolate and whey protein concentrate are the same. There's not much evidence to suggest one is better than the other. 

Which type of whey protein supplement is best for you? That comes down to individual factors, including: 

Lactose intolerance. Whey isolate is better if you have trouble digesting lactose.

Calories. If you're trying to lose weight, whey isolate has fewer calories. It's lower in carbohydrates and fat. 

Taste. You might prefer the taste of whey concentrate. The additional fat may make it more appealing than whey isolate. 

Cost. Whey isolate is more expensive. 

Whey protein is a byproduct of cheese-making. It comes in different forms, including whey powder concentrate and whey protein isolate. Both have similar health benefits, including building muscles and adding mass without weight gain. Whether you choose whey protein concentrate or whey protein isolate comes down to individual factors such as taste and cost. Whey isolate is better if you have lactose intolerance. Both types are nutritional supplements not regulated by the FDA for safety and effectiveness and may have impurities. 

What works better, whey or whey isolate?

Both types of whey protein have the same benefits. 

Who can't consume whey protein?

If you're allergic to milk, you should avoid whey protein products. They're a byproduct of the cheese-making process. 

Is it true that whey protein causes weight loss?

Some research suggests that whey protein can help you reduce fat mass. Whey concentrate may be more effective than whey isolate in this area. 

Does whey protein help in increasing stamina?

Researchers believe whey protein can help your body recover faster after a workout. That could translate into increased stamina.

What are the potential harms of whey protein?

Dietary supplements like whey protein aren't regulated by the FDA for safety and effectiveness, so they could contain impurities. If you're trying to lose weight, read the labels carefully and know how many calories you're consuming. Most people get enough protein in their diets already, so you may not need to supplement your protein intake. Whey protein is a processed food. Experts recommend limiting processed foods and making whole foods the bulk of your diet.