Whey Protein vs. Pea Protein

In response to the recent post on whey vs. collagen, a number of readers wrote in asking about pea protein. Today, I’m going to compare the two.

Before I begin, let’s get this out of the way: I’m biased toward whey protein. I sell the stuff. But the reason I sell whey protein is because I really like it, not the other way around. All my products are things that solved a problem I was having, an itch I needed to scratch. I made Primal Kitchen Mayo with avocado oil because I couldn’t find one without industrial seed oils and I didn’t want to make it fresh every time I wanted tuna salad. I put together Adaptogenic Calm (formerly Primal Calm) to help me and my buddies recover from heavy training. And so on. I made Primal Fuel out of whey protein isolate because it is the best gram-for-gram protein powder around. But pea protein is having its day in the sun now, and readers want the facts.

Common Arguments For Pea Protein

Is pea protein just as good as whey at building muscle?

Well, let’s take a look at the literature.

First of all, pea protein contains all 9 essential amino acids. That’s great.

Pea protein contains fewer branch chain amino acids—those amino acids that contribute most to muscle protein synthesis, but it does have them.

Pea protein is about 9% leucine, a very important amino acid for muscle building. Whey is 10-11% leucine, so pea comes pretty close.

In one study, resistance trained men and women in their 20s-40s were split into two groups. One group used pea protein. The other used whey protein. Both groups trained in the same manner (Crossfit-esque). At the end of 8 weeks they measured changes in muscle thickness, force production, and WOD (workout of the day) performance. Neither group had an advantage. Both groups gained about the same amount of muscle, performance, and force production.

In another study of resistance-training adults (men, aged 18-35), pea protein and whey protein resulted in similar bicep muscle gains.

That all looks pretty good for pea (and whey), but these were relatively young adults. As people age, the quality of the protein becomes ever more paramount. A young man or woman is hormonally primed for hypertrophy. Nature is working with them, not against them. If anything, they can actually get away with eating less protein than an older person of the same weight and still gain and maintain muscle because their ability to utilize dietary protein is optimized. Older people need more protein to do the same job because their ability to utilize dietary protein has degraded.

Not only do older people need high quantities of protein, they need high quality protein—bioavailable protein full of amino acids that promote muscle protein synthesis. Whey is simply higher quality on a biological level than pea protein. That difference may not show up as much in the younger person lifting and drinking protein shakes to increase their calories for mass gain, but it certainly shows up in the older person lifting and drinking protein shakes and trying to hold on to their lean mass.

Okay. You’re younger. You’re eating plenty of calories. You’re trying to gain weight. Your muscle protein synthesis capacities are optimal. You should, in theory, be fine with pea protein. Right? Sure, but why?

Pea protein is usually more expensive. It’s still technically lower quality than whey. The best justification for using pea protein to gain/maintain muscle is either you’ve got an uncle who works at a pea protein processing plant and can get you a great deal, or you’re vegan. That’s it.

All that said, pea protein looks to be the best plant-based protein around for performance in the gym. No arguments there.

What about high blood pressure? I’ve seen claims that pea protein can lower it.

Perhaps. In hypertensive rodents (probably working high stress jobs, enduring long commutes, and generally deep into the rat race), pea protein causes drastic reductions in high blood pressure, while the reductions are much more modest in humans taking pea protein daily for three weeks.

Whey does it too. In humans, a single dose of whey protein after a meal reduces postprandial blood pressure and improves arterial stiffness for up to 5 hours. It may just be the protein. Extra protein in general is great at lowering blood pressure, especially if you remove carbohydrates.

The (Relatively) Unique Strengths Of Whey Protein

The thing about protein powder is this—although whey gets most of its accolades on account of its effect on hypertrophy—gains, larger muscles, better performance, etc.—that’s not everything it can do. It also has some very unique health effects that other protein powders, most especially plant proteins like pea, do not possess.

Whey is anti-allergenic.

On the one hand, whey intolerance is the dairy protein intolerance with the lowest incidence. People are far more likely to be intolerant of or allergic to casein. But whey isn’t just less likely to be allergenic. It’s downright anti-allergenic. Whey-based formulas have shown efficacy in the prevention of allergic diseases like asthma and eczema in susceptible children and infants.

There’s no evidence that pea protein powder can do this.

Whey is anti-stress.

In “high-stress” subjects, a whey protein shake improved cognitive function and performance by increasing serotonin levels. The same shake had no effect on “low-stress” subjects. And dietary whey also lowers oxidative brain stress, at least in mice.

Pea protein may do this, but I haven’t seen the research.

Whey boosts antioxidant capacity.

Whey protein is one of the best foods we know that increase levels of glutathione—the body’s master antioxidant. We use glutathione to detoxify the liver, to metabolize alcohol and other toxic substances, to control allergic reactions, to recycle and restore to active status vitamins and antioxidants, to quell free radicals, and to perform many other vital processes.

There is simply no evidence that pea protein has the same effect. It doesn’t have enough cysteine.

Whey transforms when you digest it.

Once the whey protein hits your GI tract, many different bioactive peptides with their own unique effects are formed. In a recent review (PDF), a team of Polish researchers explored the effects of at least nine of these whey-derived peptides. Some improve blood lipids, lower blood pressure, or act as opioid receptor agonists (if you’ve ever seen a milk-drunk baby bliss out after nursing, his opioid receptors are likely being severely agonized by bioactive peptides). Others induce satiety and improve metabolic health biomarkers.

I’m sure other proteins change when digested, but their effects haven’t been studied as closely as whey.

Bioactive Components In Whey (But Not Pea Protein)

There are also a number of bioactive components in whey protein that are not in pea protein:




  • Improves bone healing and prevents bone loss.
  • Chelates excessive iron, preventing it from fueling infections (many bacteria require iron), increasing inflammation, or becoming carcinogenic.
  • Has anti-bacterial effects against food pathogens like E. coli and Listeria.

Immuno-globulins (A, M, G)

Could pea protein have similar aspects that have yet to be quantified and studied? Perhaps. But I doubt it.

After all, whey was designed by evolutionary processes to be food for other entities. It’s meant to be consumed—that’s its express purpose, and it’s why it has so many interesting bioactive components that support health.  Pea protein was not, and likely does not.

Again, if you’re vegan and looking to gain muscle, pea protein is a great choice. But if you’re not, and you’re interested in other aspects of health, whey protein is the much better option.

Thanks for reading, everyone. Take care!


Banaszek A, Townsend JR, Bender D, Vantrease WC, Marshall AC, Johnson KD. The Effects of Whey vs. Pea Protein on Physical Adaptations Following 8-Weeks of High-Intensity Functional Training (HIFT): A Pilot Study. Sports (Basel). 2019;7(1)

Babault N, Païzis C, Deley G, et al. Pea proteins oral supplementation promotes muscle thickness gains during resistance training: a double-blind, randomized, Placebo-controlled clinical trial vs. Whey protein. J Int Soc Sports Nutr. 2015;12(1):3.

Teunissen-beekman KF, Dopheide J, Geleijnse JM, et al. Protein supplementation lowers blood pressure in overweight adults: effect of dietary proteins on blood pressure (PROPRES), a randomized trial. Am J Clin Nutr. 2012;95(4):966-71.

Bumrungpert A, Pavadhgul P, Nunthanawanich P, Sirikanchanarod A, Adulbhan A. Whey Protein Supplementation Improves Nutritional Status, Glutathione Levels, and Immune Function in Cancer Patients: A Randomized, Double-Blind Controlled Trial. J Med Food. 2018;21(6):612-616.

Chandra RK. Food hypersensitivity and allergic diseases. Eur J Clin Nutr. 2002;56 Suppl 3:S54-6.

Markus CR, Olivier B, De haan EH. Whey protein rich in alpha-lactalbumin increases the ratio of plasma tryptophan to the sum of the other large neutral amino acids and improves cognitive performance in stress-vulnerable subjects. Am J Clin Nutr. 2002;75(6):1051-6.

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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