Whey vs. Pea Protein Powder: Amino Acid Comparison


While whey is the “gold standard” for non-plant protein powders, pea is usually the main one in plant powders.

Pea protein is the most popular to use in vegan protein powders.

It’s cheap for manufacturers, and tastes pretty good.

This is a quick comparison of the 2 to see how pea stacks up against whey.

Amino Acid Profiles of Whey and Pea

Below is a table of the essential amino acids in each protein source, alongside the levels a “complete” protein should have, defined by the WHO:

Amino Acid Complete Protein (min %) Pea Protein (%) Whey Protein (%)
Histidine 1.5 2.5 1.7
Isoleucine 3 4.8 6.4
Leucine 5.9 8.5 10.6
Lysine 4.5 7.5 9.6
Methionine+Cysteine 2.2 1.9 4.4
Phenylalanine+Tyrosine 3 5.5 5.6
Threonine 2.3 3.7 6.7
Valine 3.9 5 5.9

Whey protein exceeds the minimum percentage for each essential amino acid group, not surprisingly.

Pea protein is almost complete, but falls a bit short when it comes to methionine+cysteine. Breaking it down further, the issue is that it’s low on methionine.

Is Whey Protein Better Than Pea Protein?

For a long time, people have believed that a protein being complete is the most important thing.

In reality, your diet likely doesn’t consist of 100% pea protein powder, which means you probably consume a few other sources high in methionine to balance things out (e.g. seeds, wheat gluten).

There are bioavailability scores like PDCAAS, but those tests are pretty flawed. They’re based on the “limiting” amino acid in an isolated protein source, so of course whey scores much better than plant sources.

Research on Whey vs. Pea Protein Supplements

In reality, I’d rather focus on practical studies.

This study compared supplementing with pea protein vs whey protein after high intensity training for 8 weeks. They found:

We conclude that ingestion of whey and pea protein produce similar outcomes in measurements of body composition, muscle thickness, force production, WOD performance and strength following 8-weeks of HIFT

There was no difference between the 2 groups.

While that’s just one study, I think for anyone who isn’t a professional athlete, it’s reasonable to conclude that it really doesn’t matter if you supplement with whey or pea protein.

Just make sure to include other protein sources in your diet if you go with pea.

About the author

Dale Cudmore

Your friendly neighborhood vegan from Toronto. Chemical engineer turned semi-professional soccer player and freelance nutrition writer. I've been vegan for years and try to make life easier for others by sharing what I've learned.