Pea and Other Plant Proteins vs Whey ProteinWhat’s different, what’s not, and who each is for

We scored 40 powders, 20 whey and 20 plant, on protein per scoop, cost and testing records, and read the trials that compared them head to head. The two are closer than the labels suggest, and the real differences are easy to work around.

This article is general information, not personal medical or nutrition advice. If you have a kidney condition, a food allergy or a diet prescribed by your clinician, check with them before adding a protein powder. Read our health disclaimer.

Every number in this article is footnoted to its source, and the product figures come from our own scoring, which anyone can reproduce. See the footnotes.

At a glance

What they have in common

Whey and plant protein powders are made the same basic way: start with a food, strip out most of the fat and carbohydrate, and dry what’s left into a powder that is mostly protein. Whey starts as milk. Plant powders start mostly with yellow peas, often mixed with rice, pumpkin seed or other plants. 18 of the 20 plant powders we scored contain pea.

Both count toward the same daily protein total. For most adults, reaching that total across the day is a bigger lever than which powder supplies it.⁷ If you haven’t worked out your range yet, our protein calculator shows you where the main guidelines land for your age, weight and activity.

Both are also checked the same way before they reach the shelf, which is to say not at all. Under federal law, the FDA does not approve dietary supplements for safety or effectiveness before they are sold.⁸ That is why we look for independent testing programs that publish a public record (more on that below).

Where they differ

Here is the side-by-side. The protein, cost and testing figures come from our own scoring of 20 whey and 20 plant powders, priced at Amazon in October 2026; the amino acid figures come from published research.

1. Amino acids: the real difference, and a fixable one

Protein is built from amino acids, and nine of them are “essential,” meaning your body can’t make them and has to get them from food. A protein that supplies all nine in useful amounts is often called “complete.”

Whey is about as complete as proteins get. Pea protein contains all nine, but it runs low in methionine.^5,6 That gap matters most if pea protein were your only protein, which it almost never is. Rice protein is low in a different amino acid (lysine), so pea and rice cover each other, which is why so many plant powders are pea and rice blends.⁶ Eggs, dairy, fish, grains and many other foods fill the same gap across a day.

There is also leucine, the amino acid most closely linked to switching on muscle building. Plant protein isolates carry less of it on average than animal proteins.⁶ On paper, a plant scoop roughly a quarter larger closes that gap. In practice, the trials below suggest the difference is small when total protein is adequate.

2. What the studies show

The research comparing pea and whey directly is encouraging but thin: two trials, both in younger, active adults.

The broader picture comes from a 2025 review of 43 trials comparing plant and animal protein. Soy matched milk protein for muscle mass. Other plant proteins (the review’s group included rice, chia, oat and potato) came out slightly behind on muscle mass, and there was no difference in strength or physical performance. In adults 60 and older, the review found no significant difference in muscle mass either way.⁷

3. Your stomach: lactose, allergies and added fibers

Whey isolate is filtered to at least 90% protein, which leaves little room for lactose. Whey concentrate ranges widely in protein content, and more of the rest is lactose.⁴ Many people with lactose intolerance handle small amounts of lactose without symptoms, so an isolate is often worth trying, but tolerance is individual.⁹

Plant powders have no lactose, but some bring other ingredients worth checking: soy, peanut, or added fibers such as inulin. If a powder doesn’t sit well, the ingredient list is the first place to look.

4. Protein per scoop and per calorie

Whey is mostly protein; many plant powders add creamers, fibers, greens or “superfood” blends. That’s the main reason the typical plant scoop delivers less protein for its calories (16.7 g per 100 calories vs 20.8 g for whey).³ It isn’t pea itself: the plainest pea powder we scored, a single-ingredient pea protein, delivered 22.5 g per 100 calories, level with the best whey isolates (22.7 g).

Protein per 100 Calories is a measure of what’s in the scoop. It is not a measure of protein quality, fullness or weight outcomes.

5. Cost

Compare powders by cost per 30 g of protein, not by tub price. Tubs vary in size, scoop size and protein per scoop, so the tub price tells you almost nothing. On that fair basis, whey and plant cost about the same: $2.37 vs $2.43 for 30 g of protein in the typical product.³ The plant field has the wider spread, from $0.85 for a large bag of plain pea protein to $4.94 for a premium pea shake.

6. Testing records and heavy metals

Because nobody approves protein powders before sale, we give credit for independent programs that test products and publish a record you can look up yourself: NSF Certified for Sport, Informed Sport and Informed Choice. 9 of the 20 whey powders and 8 of the 20 plant powders held one we could confirm.³ How we score explains exactly what earns credit.

Pea protein vs whey, head to head

To compare the proteins rather than the recipes, here are the four simplest powders we scored: one or two ingredients, unflavored.

Prices as checked at Amazon, October 15 to 16, 2026. Naked Pea’s price is for a 5 lb bag; the others are smaller tubs, so part of its lead is the bag size.³

Stripped to the protein, pea and whey look closer than the category averages suggest. The differences that remain are the ones above: amino acid balance, lactose, and taste and texture, which only your own kitchen can judge.

Is plant or vegan protein as good as whey?

Pea matched whey in two small trials, and soy matched milk protein across many. Whey still delivers more protein and more leucine per scoop and per calorie, so a plant powder may need a slightly larger serving. Getting enough total protein and doing resistance exercise matter more than the source.^1,2,7

Who each is for

How to choose, in four steps

1. Rule things out first. A milk allergy or a vegan diet makes the choice for you: plant. Lactose trouble points to a whey isolate or plant.
2. Compare cost per 30 g of protein, and protein per scoop, rather than the price on the tub.
3. Look for a testing record you can check. A certification counts only if the program’s own registry lists that exact product. How we score shows how we check.
4. Buy the smallest size first. Taste and texture vary more than any number on the label, especially with plant blends.