Whey Isolate vs Concentrate vs Plant Protein: What the Label Words Mean
Protein powder labels use a handful of words that sound alike but mean different things: whey concentrate, whey isolate, casein, pea protein, plant blend, egg white and collagen. Each one tells you where the protein came from and how it was processed, which in turn tells you a lot about lactose, allergens, texture and how the powder fits your diet.
The short answer: whey concentrate and whey isolate both come from milk, and isolate is processed further so it carries a higher share of protein with less fat and lactose. Casein is the other milk protein. Plant powders use pea alone or a blend of plants and contain no milk. Egg white and collagen are animal options made without milk ingredients (both labels we carry note a facility that also processes milk), and collagen is an incomplete protein. This explainer walks through each type, with examples from the powders we carry.
How we wrote this: definitions come from the U.S. Department of Agriculture and the National Library of Medicine, linked in each section. Product examples use the published label facts on each product page. We have not tested these products, and nothing here is advice on how much protein to take.
Where whey and casein come from
Milk protein has two main parts. A USDA technical report on whey protein concentrate describes milk protein as roughly 80% casein and 20% whey. During cheese making, the casein forms the curd, and whey is the liquid left behind, rich in proteins, minerals and lactose. That liquid is filtered and dried into the whey ingredients you see on protein labels.
So every whey and casein powder is a milk product. If you avoid dairy or have a milk allergy, skip to the plant, egg white and collagen sections below.
Whey protein concentrate
Concentrate is whey that has been filtered to raise its protein content. The same USDA report puts whey protein concentrates at 25 to 89 percent protein, so the term covers a wide range. The rest is mostly lactose, fat and minerals that the filtering did not remove.
In our lineup, Naked Whey Grass-Fed Unflavored is a single-ingredient concentrate with 25 g of protein per serving and no sweeteners or flavors. Its label notes that concentrate contains some lactose. Plain concentrates like this one are easy to use in smoothies, oatmeal and baking because there is no added flavor to work around.
Whey protein isolate
Isolate goes through extra filtering. According to the USDA report, whey protein isolate contains at least 90 percent protein on a dry weight basis, with little fat, lactose or mineral content. That is why shoppers who are sensitive to lactose often reach for an isolate first. It still comes from milk, so it is not dairy-free, and “little lactose” is not the same as none.
Isolates in our catalog:
- Momentous Grass-Fed Whey Protein Isolate lists 20 g of protein per scoop and carries NSF Certified for Sport.
- Thorne Whey Protein Isolate lists 21 g of protein per scoop and is also NSF Certified for Sport.
- Transparent Labs Grass-Fed Whey Protein Isolate lists 28 g of protein per scoop from six ingredients.
- SEEQ Clear Whey Protein Isolate, Juicy Peach is a clear whey that mixes with water into a light, juice-style drink rather than a milky shake.
Blends of isolate and concentrate
Many everyday powders mix more than one form of whey. Optimum Nutrition Gold Standard 100% Whey lists whey protein isolate, whey protein concentrate and hydrolyzed whey, for 24 g of protein per scoop. Because it includes concentrate, a blend will carry some lactose.
Casein
Casein is the larger share of milk protein, the part that forms cheese curd in the USDA’s description. Ascent Micellar Casein, Chocolate lists 25 g of protein per scoop, and the brand describes it as slow-digesting. Like whey, it contains milk.
Plant protein: pea and plant blends
You do not need animal products to get enough protein, according to MedlinePlus from the National Library of Medicine, which lists soy, beans, legumes, nut butters and some grains among plant sources. Plant powders take one of two routes: a single source, usually pea, or a blend of several plants.
- Naked Pea Protein, Unflavored is one ingredient, yellow pea protein, with 27 g of protein per serving. Skip it if you have a pea or legume allergy. Our pea protein label guide reads its label line by line.
- Orgain Organic Plant-Based Protein Powder blends organic pea, brown rice, mung bean and chia for 21 g of protein per two-scoop serving.
- Ritual Essential Protein Daily Shake 18+ uses organic pea protein for 20 g of protein per serving, sweetened with Reb M and monk fruit.
Plant powders contain no milk, but check the facility statement if you have a milk allergy, and expect unflavored versions to taste plain on their own. Our vegan supplements and protein powders list covers which ones are labeled vegan, and our dairy-free snacks and supplements picks go beyond protein powder.
Egg white and collagen
Two animal options made without milk ingredients round out the shelf; both labels note a facility that also processes milk. NOW Sports Egg White Protein, Unflavored lists 15 g of protein per quarter cup from pasteurized egg white, and its label gives a baking swap for fresh egg whites. Skip it if you have an egg allergy. Our egg white protein label guide reads its label line by line.
Vital Proteins Collagen Peptides, Unflavored is a single ingredient, bovine collagen peptides, with 18 g of protein per serving. The Vital Proteins label itself states that collagen is an incomplete protein, so it works better as an add-on in coffee or smoothies than as your only protein powder. It is not suitable for vegans or vegetarians.
Side by side
| Type | Source | Contains milk | Our examples |
|---|---|---|---|
| Whey concentrate | Milk (whey) | Yes, with some lactose | Naked Whey |
| Whey isolate | Milk (whey), filtered further | Yes, with little lactose | Momentous, Thorne, Transparent Labs, SEEQ |
| Whey blend | Milk (isolate, concentrate, hydrolyzed) | Yes | Optimum Nutrition Gold Standard |
| Casein | Milk (curd protein) | Yes | Ascent Micellar Casein |
| Pea or plant blend | Pea, rice, mung bean, chia | No | Naked Pea, Orgain, Ritual |
| Egg white | Egg | No | NOW Sports Egg White |
| Collagen | Bovine collagen | No (incomplete protein) | Vital Proteins |
Which type fits you
If you avoid dairy
Start with pea or plant blends, or with egg white if eggs suit you, and read each label’s facility statement if you have a milk allergy. Whey and casein are out, isolate included.
If lactose bothers you but milk protein does not
An isolate carries little lactose by definition, while a concentrate or a blend that includes concentrate carries more. Check the ingredient list for the word “concentrate,” and talk to your doctor if you are unsure how much lactose you can handle.
If you compete in a tested sport
The protein type matters less than the testing mark. Look for a program such as NSF Certified for Sport on the exact product; our third party tested supplements and protein powders list shows which powders carry one.
If you mostly cook or bake
Unflavored single-ingredient powders such as Naked Whey, Naked Pea and NOW Sports Egg White leave your recipe’s flavor alone.
If you dislike thick shakes
A clear whey isolate such as SEEQ mixes with water into a light, juice-style drink instead of a milky shake.
Whichever type you pick, compare grams of protein per serving rather than scoops, and read the sweeteners and allergens on the label. Our protein cost per gram guide shows how to compare them by price. Our protein powder buying guide covers those steps in detail, and the guide on how to read a supplement label explains the Supplement Facts panel some of these powders use. For a line-by-line read of six whey tubs, see how to read a whey protein powder label.
FAQ
Is whey isolate lactose-free?
Not necessarily. The USDA report describes isolate as containing little lactose, which is less than a concentrate but not zero. It is still a milk product, so it is not suitable for a milk allergy.
What is the difference between whey isolate and whey concentrate?
Both come from whey. Concentrate is 25 to 89 percent protein, while isolate is filtered further to at least 90 percent protein with less fat and lactose, according to the same USDA report.
Is casein the same as whey?
No. Both are milk proteins, but casein is the part that forms cheese curd and whey is the liquid left after. Casein makes up the larger share of milk protein. Our casein protein label guide reads a casein bag line by line.
Can plant protein replace whey?
For many people, yes. MedlinePlus notes that you do not need animal products to get all the protein you need. Pea and plant blend powders are made without milk ingredients.
Is collagen a complete protein?
No. The Vital Proteins label states that collagen peptides are an incomplete protein, so use collagen as an extra rather than your main protein source.
Should I talk to my doctor before using protein powder?
Talk to your doctor before starting a new supplement, especially if you are pregnant, nursing, take medication or have a health condition. This applies to the powders here sold with Supplement Facts, including Momentous, Ritual, Thorne, Vital Proteins and NOW Sports Egg White.
Browse every type in our protein powders and shakes collection, or see our high-protein snacks if you would rather get protein from food.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.