Skip to Content

What is the downside of pea protein?

Pea protein has become increasingly popular in recent years as a plant-based protein source. It is extracted from yellow split peas and is often used as a vegan alternative to whey or soy protein. While pea protein certainly has some benefits, there are also a few potential downsides to consider.


One of the main downsides of pea protein is its incomplete amino acid profile. While pea protein contains high levels of the amino acids arginine and lysine, it is relatively low in the amino acid methionine. This means that pea protein does not provide all of the essential amino acids your body needs, unlike animal-based proteins like whey.

Amino Acid Pea Protein Whey Protein
Lysine 7.1% 9.0%
Leucine 7.1% 11.1%
Isoleucine 4.7% 6.6%
Methionine 1.0% 2.3%

To compensate for this lower methionine content, pea protein is often blended with rice protein or other proteins to provide a more balanced amino acid profile.


Another downside of pea protein is that it can be harder to digest than animal-based proteins like whey. This is because pea protein, like other plant proteins, contains higher levels of fibers, lectins, and other antinutrients that can irritate the digestive tract.

One study found the digestibility of pea protein to be around 88%, compared to 97% for whey protein isolate. The indigestible fibers and carbohydrates in pea protein can potentially cause more gas, bloating, and stomach discomfort, especially when consuming larger amounts.

Texture and Solubility

Pea protein has a grittier, grainier texture compared to smooth proteins like whey and casein. This texture issue also leads to poorer solubility – pea protein does not blend as easily into liquids.

Manufacturers often treat pea protein isolates to try to improve solubility. However, many pea protein powders still clump and do not achieve the same smooth, creamy consistency as whey protein drinks.

Phytates Content

Peas contain phytic acid or phytates, which are antinutrients that can bind to minerals like iron, zinc, magnesium and calcium. This makes these minerals less absorbable when consuming pea protein.

Those vulnerable to lower iron levels, like teenage girls and women, should take note of this. The phytates can inhibit iron absorption from pea protein-based meals and shakes.

Oxalate Content

Peas contain oxalic acid and oxalates. For most people oxalates do not cause any issues. However, for those prone to kidney stones, a diet high in oxalates may be a concern.

People with a history of calcium oxalate kidney stones may want to limit or avoid higher oxalate foods like peas. This would also apply to pea protein isolates.


While pea protein production has lower environmental impacts than animal proteins, it does still require agricultural land, water, and energy to grow, harvest and process peas.

There are concerns in regions like Canada over the environmental sustainability if pea demand expands greatly. Issues like biodiversity, soil health, and water use would need to be monitored.

That said, pea protein remains far more sustainable than dairy or meat proteins. But the scaling of pea protein is not entirely without environmental considerations.


Like other legumes, peas can trigger allergic reactions in some people. Pea protein isolates still contain trace amounts of other pea compounds that may be allergenic.

Those with known sensitivities or allergies to peas should be cautious about using isolated pea protein products.


Pea protein powder tends to cost more than popular proteins like whey. Part of this is economies of scale, as pea protein production is a smaller industry. The processing requirements to extract and isolate the pea protein also impact costs.

Consumers can expect to pay around 20-50% more for pea protein versus whey protein products.


Pea protein has a distinctive taste that some find unpleasant or bitter. It does not have a neutral flavor like whey protein. The texture also results in thicker, less drinkable protein shakes.

While flavored pea proteins can mask the taste, those sensitive to texture and flavor may not enjoy unflavored pea protein powders in smoothies or drinks.


Pea protein offers an excellent vegan-friendly, environmentally sustainable protein choice. However, there are some downsides in terms of digestibility, amino acid levels, taste, and cost versus animal-based proteins.

Those with food intolerances or allergies, kidney issues, or on a budget may want to consider both the pros and cons before choosing a pea protein powder.

For most healthy individuals, pea protein offers a useful rotating source of plant-based protein. But some supplementation with rice or hemp proteins may help counter the lower methionine levels in pea protein.