Whey vs Pea Protein: Which is Better for Building Muscle?

Is pea protein as good as whey for building muscle?

Most people aren’t going to see much of a difference in results with whey or pea protein supplements, just as long as they’re eating enough protein.

But if I had to choose one or the other, it would be whey.

On paper at least, whey protein does have a number of advantages over pea protein. It’s higher in essential amino acids (which play an important role in stimulating muscle growth), has a higher bioavailability, tastes better and is easier to mix.

On the downside, whey protein comes from milk, so it’s not suitable for vegan lifters.

Whey also contains lactose in varying amounts, depending on the type of whey you’re using. If you have trouble digesting lactose, then pea protein (or a blend of plant-based protein sources) is a better alternative to whey.

But if you’re not vegan, have no plans to reduce your intake of animal products, and have no problems digesting lactose, whey would be the one I’d go for.

Here’s why I think whey has the edge over pea protein.

Whey Protein Benefits

For one, whey is significantly higher in essential amino acids than pea protein.

That matters, because essential amino acids play an important role in stimulating muscle growth. Studies show that the essential amino acid composition of a protein source is predictive of its anabolic properties [1].

Put differently, there’s a link between the essential amino acid content of a given food and the extent to which eating that food increases muscle protein synthesis, a key driving force behind muscle growth [2].

In fact, you’d need around 50% more pea protein powder to get the same level of essential amino acids you’d get from an equivalent amount of whey [3]. 

Although pea protein contains all nine of the essential amino acids, it’s relatively low in methionine. By way of comparison, 100 grams of pea protein contains just 0.3 grams of methionine. The methionine content of whey protein is six-fold higher, at 1.8 grams [3].

Of course, you can just take a larger serving of pea protein to get the same amount of essential amino acids you’d get from whey.

Although it’s going to vary depending on the specific products you’re comparing, the results from one study suggest that you’d need around 46 grams of pea protein powder to get the same amount of essential amino acids you’d get from 32 grams of whey [3].

And that number is based on an analysis of both protein powders. It doesn’t take into account what happens when those protein sources are eaten and digested.

Whey protein actually has a higher bioavailability than pea protein. This means that your body absorbs more of the amino acids in whey than it does from pea protein [4].

Whey vs Pea Protein Taste

Whey also mixes easier and (in my opinion at least) tastes a lot better.

Pea protein has been described as having an “earthy and grainy” texture. That’s putting a positive spin on it. Some of the pea protein powders I tried taste like they’ve been scraped off the foot of a medieval peasant.

However, taste is a highly subjective matter. What tastes good to me won’t necessarily taste good to you. 

And there are many different pea protein supplements out there, all with different particle sizes, flavorings, textures and so on. They’re not all going to taste the same.

If you do decide to go with pea protein, it’s worth experimenting with a few different brands and products until you find one you can tolerate.

Whey vs Pea Protein for Muscle Growth: The Science

There aren’t many studies to compare whey and pea protein in terms of their effect on muscle growth. After several hours of searching, I found just two.

Both trials appear to show little difference in results between whey and pea. But only until you dig a little deeper into the way each study was done.

The first study I came across to compare whey and pea was published back in 2015 [5]. The researchers recruited a group of healthy but untrained young men, and assigned them to one of three groups:

• Pea
• Whey
• Placebo 

All three groups followed the same training program, working their upper body three times a week with the bench press, lat pulldown and biceps curl.

The protein supplements were taken twice a day, with each dose containing around 25 grams of protein from pea protein isolate (NUTRALYS®) or whey protein concentrate. 

On training days, one dose was taken in the morning and the second just after training. On non-training days, one dose was taken in the morning and the second dose in the afternoon. 

What happened? Who gained the most muscle?

After 12 weeks of training, ultrasound scans of the biceps show no difference in the rate of muscle growth between the whey and pea protein groups.

Whether the men took whey or pea protein, the results were much the same.

However, one of the major limitations of this study is the fact there was no attempt at dietary control. This means we have no idea how many calories or protein the subjects were eating. 

Nutrient intake in one group could have been very different from the other, which could have skewed the results.

It’s also worth pointing out that the study was funded by Roquette, a company that manufactures a pea protein product called NUTRALYS®. Three of the study authors were also employed by Roquette.

Every study has to be paid for by somebody. Just because a trial has been funded by a company with a vested interest in the outcome doesn’t mean you should ignore it. But there is a potential conflict of interest that you need to consider.

A similar study looked at the effects of whey and pea protein supplementation on gains in muscle size and strength following eight weeks of CrossFit training [6].

Participants trained four days a week, consuming 24 grams of protein from either whey or pea protein before and after exercise on training days, and between meals on non-training days. 

The result?

After eight weeks of training, the researchers report that both groups saw similar outcomes in terms of body composition, muscle thickness, force production, Workout of the Day (WOD) performance and strength.

However, by “similar outcomes,” what they actually mean is that nothing much happened.

Other than a small increase in one-rep max in the squat and deadlift, eight weeks of CrossFit training had no effect on body composition, muscle thickness, force production, or WOD performance.

In other words, the training program used in this study didn’t improve most of the things that were being measured.

You’re going to need a much larger group of subjects (there were only 7-8 subjects in each group), and a training program that improves the things it’s supposed to improve to get a better idea about how pea protein stacks up against whey.

What’s more, both studies lasted between 8-12 weeks. That isn’t always long enough to detect statistically significant differences in muscle growth.

A longer period of time (4–6 months) may be needed before you see any meaningful difference in results between the two protein sources.

Other than those two studies, there isn’t much else out there.

There is research to show that a blend of different protein sources (such as wheat, corn and pea) compare favorably to whey protein when it comes to stimulating muscle protein synthesis [7].

Supplementation with whey has also been shown to do a much better job of reducing blood-based markers of exercise-induced muscle damage than pea protein [8, 9].

But that’s about it.

Can You Build Muscle with Pea Protein?

In practical terms, a lot of people aren’t going to see a major difference in gains whether they use whey or pea protein.

When it comes to building muscle, your total daily protein intake matters more than the individual type of protein you’re using [11].

Protein quality is only likely to be a concern if your total protein intake is on the low side, or if you’re consuming a largely plant-based diet.

There was one study done in the late 1990’s, which shows a faster rate of muscle growth with an omnivorous (meat-containing) diet versus a lacto-ovo-vegetarian (excludes meat, poultry, and fish but includes eggs and dairy products) diet [12].

After lifting weights twice a week for three months, it was subjects on the omnivorous diet who gained the most muscle.

However, while daily protein intake wasn’t statistically different between the two groups, it was slightly higher in the meat-eaters versus the vegetarians. 

In other words, it’s possible that the higher protein intake, rather than protein quality, was responsible for the extra gains.

A follow-up study shows no difference in muscle growth with a lacto-ovo-vegetarian diet compared to an omnivorous diet providing similar amounts of protein [13].

In most cases, dairy and eggs (as well as fish if you’re on a pescatarian diet) give you all the high-quality protein you need to maximize muscle growth. You’ll do just as well as you would have done if meat and poultry were on the menu.

It’s a slightly different story if you’re on a vegan diet, which eliminates meat, fish, poultry, eggs and dairy products.

Compared to a vegetarian diet, vegans are going to have a harder time eating enough high-quality protein, which has the potential to put the brakes on muscle growth.

For vegan lifters, there may be a benefit in consuming slightly more protein than people who eat animal products.

That is, omnivorous lifters can maximize muscle growth with around 0.7 grams of protein per pound of bodyweight per day. Vegan lifters may need a little more, somewhere in the region of 0.8 grams of protein per pound of bodyweight per day.

Pea vs Whey Protein: Nutrition Comparison

The nutritional content of a typical 30-gram serving of a pea and whey protein isolate (chocolate flavour) looks like this.

Nutrition	Pea	Whey
Calories	101	108
Protein (grams)	21.3	24.3
Carbohydrate (grams)	1.4	3.6
Fat (grams)	0.3	0.6

Pea Protein vs Whey: Amino Acid Profile

Here’s how the amino acid content of a pea protein isolate compares to a whey protein isolate, with the data coming from this study.

The values are presented in grams per 100 grams of raw material.

Amino Acid	Pea	Whey
Threonine	2.5	5.4
Methionine	0.3	1.8
Phenylalanine	3.7	2.5
Histidine	1.6	1.4
Lysine	4.7	7.1
Valine	2.7	3.5
Isoleucine	2.3	3.8
Leucine	5.7	8.6
Serine	3.6	4.0
Glycine	2.8	1.5
Glutamic Acid	12.9	15.5
Proline	3.1	4.8
Cysteine	0.2	0.8
Alanine	3.2	4.2
Tyrosine	2.6	2.4
Arginine	5.9	1.7

Here’s the essential (EAA) and branched chain amino acid (BCAA) content of whey and pea protein, per 100 grams of raw material.

Essential Amino Acids

• Whey 34 grams
• Pea 24 grams

BCAAs

• Whey 16 grams
• Pea 11 grams

How is Pea Protein Made?

The outer shell of the pea, which consists mainly of fiber, is removed.

What’s left is then ground down into a fine flour containing fiber, carbohydrate and protein.

The flour is mixed with water to remove the carbohydrate and fiber, then dried in a multi-stage spray dryer. This leaves a pea protein isolate containing around 85% protein.

How is Whey Protein Made?

Milk is made up of two major proteins, casein and whey. Roughly 80% of milk protein is casein, with the remaining 20% coming from whey.

Enzymes are added to milk to separate the whey and casein. Once the whey has been separated from casein, it’s filtered to remove the fat and carbohydrate. The resulting whey protein liquid is then dried, which leaves you with whey protein powder.

There are also several different types of whey protein. These are known as whey protein concentrates, whey protein isolates and hydrolyzed whey protein. A hydrolyzed whey protein is one that’s been partially pre-digested by being broken down into smaller pieces.

In general, a whey protein isolate will contain more protein and less carbohydrate (as lactose) and fat compared to a concentrate.

One hundred grams of an unflavoured whey protein concentrate, for example, contains around 75 grams of protein, 6 grams of fat and 6 grams of carbohydrate.

The composition of an unflavoured whey protein isolate is slightly different, containing more protein (90 grams of protein per 100 grams of powder) and less carbohydrate and fat.