In recent years, pea protein has become an incredibly popular dietary supplement amongst everyone from vegans and vegetarians to your average, everyday gym-goer.  This recent uptick in popularity, in turn, has lead many to wonder how it stacks up against the OG of protein supplements — whey.  

That’s why in this article, we’re doing an in-depth comparison of pea protein vs whey to give you a clear picture of what it is exactly that sets each type of protein apart.  But before we dive too deep into our analysis, lets first talk about what pea protein and whey actually are and where they come from.     

What is Pea Protein?

Just like the name implies, pea protein is derived from peas.  It’s usually extracted from yellow peas, although it can technically come from other kinds of peas as well.  

It’s completely plant-based, does not contain any major allergens, and is gluten and lactose-free, making it a protein that most people are able to tolerate without issue.  

Pea protein can come in a couple of different forms — pea protein isolate (PPI) and pea protein concentrate (PPC).  Usually, PPI is around 80% pure protein, meaning that much of the carbs, fat, and other nutrients have been removed during processing.(1) PPC, on the other hand, is considerably less pure and can have a protein content as low as 30%.      

What is Whey Protein?

Whey protein, on the other hand, is an animal-based protein derived from cows milk — it makes up about 20% of all the proteins found in milk, while casein makes up the other 80%.   

Just like with pea protein, whey can also come in the form of either concentrate or isolate.  Whey protein concentrate (WPC) is what you get when whey is separated from the casein protein that’s also in milk — at this point, there is still a decent amount of lactose (and fat) leftover with the whey, which means that it may not be suitable for those with lactose issues — lactose is a complex sugar that some people have trouble digesting.(2)

In contrast, whey protein isolate (WPI) is usually 90+% pure protein, meaning that most of the lactose (and fat) have been removed during processing  — that’s why people with less severe lactose issues can usually consume WPI without issue.(3)

Pea Protein vs. Whey: An In-Depth Comparison

Not only do pea protein and whey come from different sources but they also each have their own unique qualities as far as proteins go.  

On top of having different amino acid profiles and biological values, pea protein and whey also differ when it comes to how long it takes them to be absorbed during digestion.  

1. Amino Acid Content

One of the major differences between pea protein and whey has to do with their amino acid content.  Amino acids (AAs) are known as the building blocks of protein because they make up the structural foundation upon which proteins are built. 

Essential amino acids (EAAs) are amino acids that your body cannot produce on its and, therefore, must be obtained from dietary sources.  There are 9 essential amino acids in total and a protein that contains all 9 is known as a complete protein.(4)

When we’re talking about a protein’s amino acid content, we’re not only interested in whether or not it’s a complete protein, but we also want to know how much of each essential amino acid it contains.  In other words, not only do we want to see that a protein contains all 9 essential amino acids, but we also want to see that all 9 of those EAAs are present in adequate amounts.(5)

In simple terms, a complete protein with a good distribution of all 9 essential amino acids is going to be a better quality protein in comparison to a protein that is lacking in certain EAAs.  

Pea Protein Vs Whey

While pea protein technically contains all nine essential amino acids, it’s considered to be an inadequate source of methionine and cysteine, which is why it’s sometimes classified as an incomplete protein.  

In contrast, whey is a complete protein and has a considerably well-balanced amino acid content, containing ample amounts of all 9 EAAs and particularly high concentrations of leucine, valine, and isoleucine — the three BCAAs.  

Here’s how the amino acid contents of pea protein and whey break down; we’ve also included other types of protein for further comparison.  The following data comes from a 2018 journal article published in Amino Acids.(6) All proteins on this list were tested in the isolate form, though purity varied from protein to protein. 

Again, we’re only looking at essential amino acids here because they’re the most important.  Also, the essential amino acid tryptophan is not present on this list — it decomposed during acid hydrolysis, which prevented the researchers from detecting it in this particular study — however, both types of protein have been shown to contain moderate amounts of tryptophan in other studies.     

2. Muscle Protein Synthesis

Because they have different amino acid contents, pea protein and whey also affect the biochemical process known as muscle protein synthesis (MPS) in different ways.  There are numerous chemical pathways that are nutritionally, hormonally, and enzymatically dependent on MPS.  

When it comes to your muscles, they’re made up of proteins, which themselves are made up of amino acids.  Every day, somewhere around 1% of all your muscle proteins are broken down, requiring your body to replace them.  It’s through the process of MPS that your body takes amino acids from your diet and builds new proteins to replace the old, broken-down ones.  

But in order for this to happen, a signaling event must take place to initiate muscle protein synthesis and no EAA is more important that than leucine when it comes to setting off this signal event.  In fact, research shows that an ample amount of leucine is required to maximally stimulate MPS — i.e. the more leucine that’s present in the protein source, the greater the degree to which it can potentially spike MPS.(7)

Pea Protein vs Whey

Compared to pea protein, whey contains almost 3 more grams of leucine per 100 grams of protein (5.7g vs 8.6g), which ultimately means that it may help to stimulate muscle protein synthesis to a greater degree than pea protein.  

3. Absorption

The time it takes for each type of protein to be broken down and absorbed into the bloodstream also differs for pea and whey protein.  While some proteins are absorbed rapidly in the gastrointestinal tract, it ultimately takes other proteins much longer to be broken down and utilized by the body.(8)

Pea Protein Vs Whey

Pea protein absorbs at a moderate rate of speed, usually completing absorption in 3 – 4 hours.  While that’s not necessarily slow — a protein like casein, for example, can ultimately take up to 8 hours to be fully absorbed — pea protein takes considerably longer to absorb in comparison to whey, which is usually absorbed within 90 minutes in the case of most isolates.  

4. Biological Value 

On top of absorbing at different speeds, pea protein and whey also have different biological values (BV).  BV is essentially a measurement of how much of a protein actually gets used by the body in the formation of new tissues, after all, is said and done.(9)

More specifically, biological value looks at postprandial nitrogen balance as a means of assessing a protein’s overall usability.(10) A high biological value indicates that a protein source has a high usability and much of it is actually used in the formation of new tissues, while a low biological value indicates the exact opposite.  

Pea Protein vs Whey

In general, animal-based proteins have higher biological values in comparison to plant-based proteins(11) For example, here’s how pea protein and whey stack up against both each other and a number of other protein sources.  

Biological Values of Pea, Whey, & 6 Other Protein Sources
Protein TypeBiological Value (BV)
Pea Protein65
Whey Protein104
Casein77
Beef80
Egg100
Milk91
Soy Protein74
Wheat Gluten64

*data obtained from” Protein – Which is Best?” Published in the Journal of Sports Science and Medicine, 2004

Pea Protein vs Whey: Which One Should You Choose?

Now that we’ve gone over the technical aspects of what sets pea protein and whey apart, you’re probably wondering “Ok then, so which protein supplement should I choose?”

When it comes to supporting your overall health, whey appears to be the better protein both in terms of its amino acid content and its biological value.  It has a more evenly distributed amino acid content and contains significantly more amino acids per 100g in comparison to pea protein (34.1g vs 23.6g in the one study we look at earlier).  

Additionally, whey also has a higher biological value, which ultimately means that more of it actually gets used in the formation of new tissue when compared to the same amount of pea protein.

On top of supporting your overall health, whey protein may also be a better protein source when it comes to supporting the muscle-building process, which after all, is why many people take protein supplements to begin with.  

Due to its high leucine content and well-rounded amino acid profile, whey has been shown to spike MPS to a greater degree than any other type of protein, which ultimately is the perfect scenario for maximizing your muscle-building potential.(12)

Grass-Fed Whey

with isolate and concentrate for maximal MPS and digestive enzymes for improved digestion and absorption

Learn More

On top of that, the quick absorption time of whey makes it the ideal protein to consume post-workout — whey isolate is absorbed rapidly into the bloodstream, where it can be ferried off to muscles in need of repair within 90 minutes after consumption (compared to up to 4 hours for pea protein).  

Now with all that being said, it certainly doesn’t mean that pea protein has no benefits to offer, it’s just that whey protein is simply a higher quality protein at the end of the day.  

If we go back to our chart on the amino acid content of different proteins, we see that pea protein contains more total essential amino acids than many other plant-based proteins (including soy), which makes it a great choice for anyone who is vegan and/or those with allergies that prevent them from consuming whey.  

If you are going to supplement with pea protein, however, you’ll want to make sure that you’re mixing in other protein sources in your diet to make sure you’re getting an adequate supply of all 9 essential amino acids — this is especially important for those on strictly plant-based diets.