Whey isolate vs concentrate: what the difference means on your label
Nutriens editors
Whey isolate and whey concentrate come from the same place and do the same basic job. The difference is how far the whey is filtered, and that changes how much of each scoop is protein. One thing doesn't change at all: both are milk. If you have a milk allergy or don't eat dairy, neither is for you, and that includes our Protein Strength.
Where whey comes from
Milk has two main families of protein: casein, which is most of it, and whey, roughly a fifth. When milk is made into cheese, the casein forms the curd and the whey stays in the liquid. That liquid is filtered and dried into powder.
Whey is a complete protein, with all nine essential amino acids. The International Society of Sports Nutrition (ISSN) position stand on protein also notes it is rich in leucine and digests quickly, which is why it is a common choice after training.
Concentrate vs isolate
| Whey concentrate | Whey isolate | |
|---|---|---|
| Processing | Filtered less | Filtered further |
| Protein per gram of powder | Lower, varies widely by product | Higher, generally at least 90% protein by dry weight |
| Lactose and fat | More of both | Less of both |
| Milk allergen | Yes | Yes |
Extra filtering removes more of the lactose (milk sugar) and fat that ride along with the protein. That makes an isolate leaner per scoop. It also makes it cost more to produce, which is part of why concentrates are common in large tubs.
A third form, hydrolysate, is whey that has been partly broken down into smaller pieces. You'll see it listed as "hydrolyzed whey". It is still milk.
Milk allergy and lactose intolerance are not the same
This is the part that matters most, and the two get mixed up.
- Milk allergy is the immune system reacting to milk proteins, and whey is one of those proteins. Isolate filtering lowers lactose and fat, not the milk protein. If you are allergic to milk, whey isolate is not safe for you.
- Lactose intolerance is difficulty digesting lactose, the milk sugar. MedlinePlus, from the National Library of Medicine, describes it as a different condition from milk allergy. Because isolate is filtered further, it usually has less lactose than concentrate, but "less" isn't "none".
Milk is one of the major food allergens that U.S. law requires labels to declare, so any whey product must declare milk, usually in a "Contains milk" line. Look for that line before anything else.
How to tell which one you are buying
- Read the ingredient list. Ingredients appear in order of weight. "Whey protein isolate" and "whey protein concentrate" are named separately. Many tubs use a mix, often with concentrate first.
- Divide protein by serving size. It tells you how much of each scoop is protein once flavors, sweeteners and thickeners are in. Protein Strength Vanilla is 22 g of protein in a 34 g serving, about 65%; Chocolate is 22 g in 35 g, about 63%. The rest is flavor, cocoa, MCT oil powder, apple pectin, sunflower lecithin, stevia and sea salt.
- Check the allergen statement. It should say "Contains milk", isolate or not.
How to read a protein label takes this further, line by line.
Which one should you choose?
If you tolerate dairy well and want the most protein for the least extra, isolate is the leaner pick. Concentrate can make sense if you don't mind a little more lactose and fat. If lactose bothers you, isolate is usually easier, but ask your doctor if you are unsure. If you are allergic to milk or don't eat dairy, skip whey of every kind and build protein from foods you do eat.
Protein Strength uses whey protein isolate as its only protein source, 22 g a serving, in Vanilla and Chocolate. Both contain milk, and neither is vegan or dairy-free.
Where to go next
How to fit a shake into a real week: the Protein Strength routine. Short answers on milk, mixing and timing: the Protein Strength FAQ. Why protein slips on busy days: busy days break protein targets. Or find your formula.
References
- Jäger R, Kerksick CM, Campbell BI, et al. "International Society of Sports Nutrition Position Stand: protein and exercise." Journal of the International Society of Sports Nutrition. 2017;14:20.
- MedlinePlus, U.S. National Library of Medicine. "Lactose Intolerance." medlineplus.gov
- U.S. Food and Drug Administration. "Food Allergies: What You Need to Know." Food Allergen Labeling and Consumer Protection Act of 2004 (FALCPA).
- American Dairy Products Institute. "Whey Protein Isolate" standard, v4.0 (2023).
- Protein Strength Vanilla and Chocolate labels: nutrition panel, ingredients, allergen statement and directions.
