All things considered, pea protein powder has several advantages over soy protein powder. Read on to find out why and learn more about the benefits, differences, and potential drawbacks of soy protein vs pea protein.
Jump to:
- Who May Benefit From Protein Powders?
- Overview of Soy Protein Powder
- Overview of Pea Protein Powder
- Comparing Soy Protein vs. Pea Protein Powders
- What About Whey Protein?
- The Bottom Line: Which Protein is the Better Option?
Who May Benefit From Protein Powders?
The RDA for protein is currently 0.8 g/kg body weight. However, many experts believe this number is too low and that a better protein goal would be anywhere from 1.2-1.6 g/kg for most people, with up to 2.2 g/kg being the high end for elite athletes.
High protein diets can help with muscle gain and weight loss in the general population, but they are also important for vegans, athletes, and older adults who have higher protein needs.
Protein powders can be useful and convenient for getting in extra protein for people who follow plant-based diets. However, not everyone needs to use protein powder to be healthy or get enough protein. The majority of our nutrition should come from healthy whole food sources first.
That being said, protein powders are still helpful for those who find it hard to get enough protein with whole foods alone or those who want the convenience of having a quick option to help fill gaps.
Keep in mind that I don't recommend protein powders for children, as they aren't necessary and can include added ingredients not suitable for children.
Protein powders are not well-regulated in the market and some can have ingredients or contaminants like heavy metals that are not listed on the label. Therefore, always look for powders that are third party tested to ensure their safety.
If you aren't sure if your favorite protein powder is third party tested, you can always contact the company to confirm.
Make sure to check out my post on dairy-free protein shakes for more information on what to look for in protein powders and pre-made protein shakes.
Overview of Soy Protein Powder
Soy protein powder is a powdered form of protein extracted from soybeans. It's made by isolating the protein from defatted soybean flakes or soy flour.
Soy is a high-quality protein thatcontains all nine essential amino acids, but it's lower in methionine. It can be found in the form of soy protein isolate or soy protein concentrate.
Soy protein isolate is the most refined form of soy protein made by removing most of the fats and carbs, leaving behind almost pure protein. Alternatively, soy protein concentrate is made by removing some of the carbohydrates and fat, but retains more of the natural soy components compared to isolate.
Soy protein is often chosen by vegetarians, vegans, and those with dairy or lactose intolerances as a plant-based alternative to whey protein.However, soy is a common allergen so those with a soy allergy would want to steer clear.
Overview of Pea Protein Powder
Pea protein powder is a plant-based protein supplement derived from yellow split peas. It's made by isolating the protein from dried, ground peas, resulting in a highly concentrated source of protein.
Similar to soy protein, it can be found in the form of pea protein isolate or pea protein concentrate, with isolate being the most refined version that is highest in protein.
Pea protein powder contains all nine essential amino acids but is lower in methionine. Because of this, it's typically found as a blend with other plant-based proteins such as rice or hemp protein to create a more balanced amino acid profile.
Pea protein is naturally free from common allergens like dairy, soy, and gluten, making it suitable for people with multiple dietary restrictions or sensitivities.
Comparing Soy Protein vs. Pea Protein Powders
Nutritional Profile
Both soy protein isolate and pea protein isolate will be almost purely protein. Therefore, the amount of protein, fat, and carbs in any one protein powder product will depend on the brand and the other ingredients that are included.
I prefer to find a protein powder that is around 120 calories and 20 grams of protein so that I am getting mostly protein and not a ton of excess of fat and carbs.
Essential Amino Acids (EAA)
Both pea and soy protein meet the minimum requirements for essential amino acids (WHO/FAO/UNU) but the amino acid profile of pea protein is slightly higher at 30% of total protein while soy falls at 27% of total protein. Pea protein is also slightly higher than soy in the branched chain amino acids (BCAAs) leucine, valine, and isoleucine. Overall, pea protein products have aslightly higher amino acid content.
Essential Amino Acid Comparison
| Soy Protein Isolate | Pea Protein Isolate | |
| Threonine | 2.3 | 2.5 |
| Methionine | 0.3 | 0.3 |
| Phenylalanine | 3.2 | 3.7 |
| Histidine | 1.5 | 1.6 |
| Lysine | 3.4 | 4.7 |
| Valine | 2.2 | 2.7 |
| Isoleucine | 1.9 | 2.3 |
| Leucine | 5.0 | 5.7 |
| Total EAA | 19.9 | 23.6 |
For reference, the amount of leucine in 20g of protein from soy protein isolate vs pea protein isolate is about 1350 mg and 1420 mg respectively. The International Society of Sports Nutrition Position Stand on protein and exercise states that protein doses should contain 700-3000 mg leucine, along with a balanced EAA profile.
Both soy and pea protein are low in methionine, but plant-based protein powders are often made with protein blends, giving them a more complete amino acid profile.
Muscle Growth
Along with resistance exercise and enough total protein intake, adequate intake of leucine and essential amino acids is best for gaining muscle.
Since pea protein has slightly higher leucine and total EAA than soy protein (and different pea protein blends can provide even more), pea protein may theoreticallyhave the slight edge for muscle mass. However, science thus far suggests similar outcomes on muscle protein synthesis (aka muscle gain).
Phytoestrogens & Hormones
There's an ongoing myth that soy products will affect hormones like testosterone due to their phytoestrogen (isoflavone) content. However, meta analysis show that neither soy foods nor isoflavone supplements have an affect on testosterone.
Furthermore, there is little evidence to show that those with healthy thyroid function and adequate iodine levels will have altered thyroid function from the consumption of soy foods.
While studies on soy isoflavones can be conflicting, the overall consensus is that whole and minimally processed soy foods like tofu, tempeh, soy milk, miso, and edamame are nutrient-rich foods with many health benefits and should not be a cause for concern.
However, heavily processed soy products may have a different effect on hormones, which is an ongoing debatethat needs to be further studied. If you are concerned about soy protein powders, pea protein powders are a good option to choose instead.
Flavor & Texture
Pea protein typically has a milder, slightly sweeter flavor compared to soy protein. It may have a slightly earthy or nutty undertone, but generally, it has a more neutraltaste compared to soy.
Soy protein often has a more pronounced, slightly bean-like flavor compared to pea protein. Some people find it to be slightly bitter or chalky, especially in its unflavored form. However, flavored varieties are also available that can mask or complement the natural flavor.
Pea protein tends to have a smoother texture compared to soy protein. It dissolves relatively well and can result in a smoother consistency in shakes or baked goods. However, some people may find that pea protein has a slightly gritty texture, especially when not mixed thoroughly.
Soy protein can have a denser texture compared to pea protein. It tends to be creamier and may create a thicker consistency in shakes or recipes.
Other Considerations
Both soy and pea protein are relatively easily digestible. Protein powders isolate the protein from the whole soybean or pea, removing fiber and other substances that would contribute to digestive issues like gas and bloating.
Although GMOs have been deemed safe, if you are concerned about consuming GMOs and want to go with a soy protein powder, you can certainly look for an organic non-GMO product.
Plant protein sources tend to have a lower carbon footprint/lower environmental impact than animal protein sources, so protein supplements from soy beans or yellow peas are both a great option.
If you're concerned about oxalates and phytates, check out my post on black beans and pinto beans where I address "anti-nutrients."
What About Whey Protein?
Although some studies conclude whey increases lean mass more than plant-based proteins due to higher leucine and EAA content, a meta-analysis (which analyzes results from many studies) found that there is no difference between soy protein and whey protein on muscle gains.
While there are limited studies currently comparing pea protein and whey protein, studies we have so far show no difference between pea and whey on muscle gain.
In a randomized controlled trial of 161 men ages 18-35 who participated in resistance training for 12 weeks, there was no difference in muscle thickness increases between the pea protein vs whey protein groups.
Similarly, in an 8-week study on the effects of whey vs pea protein during high-intensity functional training, whey and pea protein produced similar outcomes for body composition, muscle thickness, performance, and muscle strength.
Altogether, the most important factor appears to be overall protein intake; high total protein intake may overcome any potential differences of plant vs animal protein on muscle.
The Bottom Line: Which Protein is the Better Option?
All things considered, pea protein powder has several advantages over soy protein powder. Although more studies have been done on soy protein thus far, pea protein is allergen-free, slightly higher in essential amino acids, and is not associated with the same potential isoflavone concerns as soy.
Additionally, using a protein powder made from peas can help to diversify the plant-based protein sources in your diet if you're regularly consuming soy products like soy milk, tofu, tempeh, edamame, etc.
Ultimately, soy and pea protein are both popular options, andthe "best" protein depends on your personal preferences, dietary restrictions, and fitness goals.
Whey may be preferred for people who consume animal products and can tolerate lactose, while vegan protein powders like soy or pea protein may be preferred by someone who avoids animal products.
If you're looking for a good vegan protein powder, my favorite is BPN's vegan protein powder in the peanut butter cookie flavor. I use it in my oatmeal essentially every morning. It's made with a blend of pea protein, watermelon seed protein, and pumpkin seed protein. It provides 21g plant-based protein per 120 calories and has no added sugar but still tastes sweet from the stevia and monk fruit.
