The Best 6 Soy Protein Powders of 2023
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Soy protein powder is an excellent protein alternative and plant-based supplement
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Medically reviewed by Kristy Del Coro, MS, RDN, LDNFact checked by Rich Scherr
Plant-based eating is becoming increasingly popular, and many of those who follow vegan diets worry about inadequate protein intake. Particularly if you are an athlete, avid gym-goer, or otherwise struggling to meet your protein needs through food alone, protein powder may be a helpful addition to your diet. While you can safely supplement your protein intake with a soy-based protein powder, you may have heard conflicting information about the impact of soy consumption on health, specifically related to soy phytoestrogens, which have estrogen-like properties.
Despite consumer doubts, research has shown that soy consumption is generally safe and, in fact, soy products may modestly improve heart health and reduce risk of certain cancers. Another bonus is that, unlike many plant-based proteins, soy protein is a complete protein, meaning it contains all nine essential amino acids, though it is low in one—methionine. To get enough methionine and generally maintain a balanced diet, sports dietitian Starla Garcia, M.Ed, RDN, LD, recommends eating soy in moderation and ensuring that you’re eating a variety of plant-based proteins (like nuts and beans).
When selecting the best soy protein powders, we consulted with sports dietitians and reviewed various options on the market, considering their ingredients, the company’s reputability, and whether they are third-party tested for contamination.
Soy protein supplementation may not be beneficial for those who have an iodine deficiency, those who are pregnant or those who have kidney problems.
Our team of registered dietitians reviews and evaluates every single supplement we recommend according to our dietary supplement methodology. From there, a registered dietitian on our Expert Review Board reviews each article for scientific accuracy. Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and which dosage to take.
Best Overall: NOW Sports Soy Protein Isolate
Buy at Betterhealthinternational.com
Pros
NSF Certified for Sport
Informed Choice certified
One ingredient
Cons
Processed in a facility with common allergens
Now Sports Soy Protein Isolate is our best overall pick because it’s gone through extensive third-party testing, contains just one ingredient, and is a good source of calcium and iron. The only ingredient in this powder is soy protein isolate, providing 20 grams of protein per serving.
It is NSF certified for sport, a third-party organization that ensures that the product contains what the label says and doesn't have any harmful contaminants or substances banned by sport, as well as Informed Sport certified, a third-party organization that tests products for prohibited substances and ensures they are manufactured to high-quality standards. In case you are looking for a third seal of approval, NOW, as a company, does thorough testing to verify the purity and potency of their products.
Now Foods’ Soy Protein Isolate is unflavored, making it versatile and easy addition to a variety of sweet or savory bases, such as smoothies, baked goods, or soups. Furthermore, it is a good source of protein and contains 15% of your daily needs of iron and calcium, two of the nutrients that may be lacking in a vegan diet.
Price at time of publication: $26 for 23 servings ($1.13 per serving)
Key specs:
Form of soy protein: soy protein isolate | Serving size: ⅓ cup | Protein per serving: 20 grams | Other ingredients: N/A | Sodium: 170 milligrams | Calcium: 193 milligrams | Iron: 3 milligrams
Best Budget: Herbal Secrets Organic Soy Protein Isolate
Pros
One ingredient
Good source of calcium and iron
Certified Organic
Third-party tested
Cons
Some may not enjoy flavor or smell
Herbal Secrets Organic Soy Protein Isolate is a good option with just one ingredient at a competitive price. If you prioritize purchasing non-GMO or certified Organic foods, then this is an especially great option. It contains 20 grams of protein per serving and 17% of the recommended daily value of iron and calcium and is versatile since it is unflavored.
Herbal Secrets reports their products are third-party tested by independent laboratories for purity, potency, and integrity. The likelihood of contamination is relatively low since this product does not contain herbal additives. It also contains a slightly higher amount of sodium than other options, at 200 milligrams per serving, which may be beneficial for athletes or active individuals to replenish some of the sodium lost in sweat.
Price at time of publication: $38 ($1.00 per serving)
Key specs:
Form of soy protein: soy protein isolate | Serving size: ⅓ cup | Protein per serving: 20 grams | Other ingredients: N/A | Sodium: 200 milligrams | Calcium: 170 milligrams | Iron: 3 milligrams
Best Single Ingredient: Nutricost Soy Protein Isolate
Pros
One ingredient
Gluten-free
Low sodium
Cons
Not third-party tested
Low in calcium and iron
Nutricost soy protein isolate is a simple product from a reputable company. While 10 grams of protein per serving might sound low, one serving is only ½ scoop. Therefore, each scoop contains 20 grams of protein, which is comparable to most other soy protein powders.
If you need to be mindful of your sodium intake, this could be a good option as it has a relatively low sodium content—just 115 milligrams, or 5% of the recommended daily value. It contains a very small amount of calcium, iron, and potassium, so this one may not be the best choice if you are looking for a powder that is high in nutrients aside from protein.
Price at time of publication: $36 ($0.44 per half scoop serving, $0.88 per full scoop serving)
Key specs:
Form of soy protein: soy protein isolate | Serving size: ½ scoop | Protein per serving: 10 grams | Other ingredients: N/A | Sodium: 115 milligrams | Calcium: 7 milligrams | Iron: 1 milligram
Related: The 11 Best Tested, Dietitian-Approved, Plant-Based Protein Powders of 2023
Best Vanilla: 365 by Whole Foods Market Soy Protein Unsweetened Vanilla Flavor
Pros
Only two ingredients
No added sweeteners
24 grams of protein per serving
Cons
Not third party tested
Expensive per serving
365 by Whole Foods Unsweetened Vanilla Soy Protein is a rare gem in the protein powder world, as it is a flavored protein powder that does not contain any added sweeteners, natural or artificial. This powder is not third-party tested, but 365 is generally a reputable brand with supplement standards detailed on the Whole Foods website.
365’s unsweetened vanilla protein powder contains only two ingredients–soy protein isolate and natural vanilla flavor—so we don’t recommend it mixed into plain water or non-dairy milk. Instead, it makes a great addition to sweet recipes. It might be especially tasty mixed into oatmeal or a smoothie and sweetened to your liking with fruit or honey.
Price at time of publication: $20 ($1.25 per serving)
Key specs:
Form of soy protein: soy protein isolate | Serving size: 1 scoop | Protein per serving: 24 grams | Other ingredients: natural vanilla flavor | Sodium: 280 milligrams | Calcium: 75 milligrams | Iron: 3 milligrams
Related: The Best-Tasting Protein Powders of 2023
Best Chocolate: Shaklee Energizing Soy Protein, Creamy Cocoa
Pros
Good source of many micronutrients
Contains protein and carbohydrates for recovery
Good source of B vitamins, phosphorus, iron and calcium
Popular for its flavor
Cons
Processed in a facility with common allergens
Not third-party tested
Expensive per serving
Shaklee’s Energizing Soy Protein powder uses soy protein isolate and cocoa flavor to create a creamy option with 14 grams of protein per serving. It contains 10 grams of carbohydrates per serving, which can contribute to meeting an athlete's high carbohydrate needs.
If you drink dairy milk, we recommend adding it to a glass of milk to add even more protein and carbohydrates and make a solid, well-rounded recovery snack. If you don’t consume dairy, try blending it into a shake with banana, peanut butter, and your favorite dairy-free milk.
This product contains more ingredients than other options, making it a more highly processed option. Take note that there is a nutrition panel and a list of “other ingredients,” but every ingredient is not listed out clearly. For those looking to add other nutrients through their protein powder, these added ingredients help make it a good source of certain B vitamins, phosphorus, iron, and calcium.
Price at time of publication: $49 ($1.63 per serving)
Key specs:
Form of soy protein: soy protein isolate | Serving size: 3 tablespoons | Protein per serving: 14 grams | Other ingredients: cocoa processed with alkali, natural cocoa flavor, soy lecithin, guar gum, potassium chloride | Sodium: 160 milligrams | Calcium: 500 milligrams | Iron: 3 milligrams
Related: The Best Pea Protein Powders, According to a Dietitian
Best Gluten-Free: Bob’s Red Mill Gluten-Free Soy Protein Powder
Pros
Only two ingredients
Certified gluten-free
Budget-friendly
Cons
Not third-party tested
Does not contain calcium
Bob’s Red Mill’s Gluten-Free Soy Protein Powder is made from just two ingredients, and it is processed in a gluten-free facility and tested for gluten-free integrity. While most soy protein powders do not contain gluten, they may not be certified gluten-free, so we recommend Bob’s Red Mill over other options if you have celiac disease or gluten sensitivity.
Bob’s Red Mill’s soy protein powder contains only soy protein isolate and soy lecithin—lecithin is a common addition to improve texture and add creaminess. While it contains 17 grams of protein and 10 percent of the recommended daily value of iron per serving, it does not contain any calcium, so you may want to be mindful of choosing other calcium-rich foods throughout your day.
Bob’s Red Mill is an employee-owned company with a commitment to quality, health, and sustainability.
Price at time of publication: $15 ($0.75 per serving)
Key specs:
Form of soy protein: soy protein isolate | Serving size: ¼ cup | Protein per serving: 17 grams | Other ingredients: soy lecithin | Sodium: 190 milligrams | Calcium: 0 milligrams | Iron: 2 milligrams
Related: The 5 Best Hemp Protein Powders Available, Recommended by a Dietitian
Are Soy Protein Powders Beneficial?
Soy protein powder can be beneficial for those with high protein needs, such as highly active individuals or competitive athletes. It can serve as an easy means of refueling to promote muscle growth and recovery after a workout. Particularly for plant-based eaters with higher protein needs, soy protein powder can be a great resource. Populations who may benefit from soy protein powder include:
Athletes. Endurance athletes’ protein needs can be nearly double those of an average sedentary adult, and strength-based athletes’ protein needs can be even higher. Therefore, as an athlete, you may benefit from supplementary forms of protein. Particularly if you are a vegan athlete, soy protein powder can be a beneficial addition to your refueling regimen since it is a complete protein. If you are not a competitive athlete but you are a highly active individual, you likely still fall into this category.
People following a plant-based diet. A common concern for people eating plant-based is inadequate protein consumption. While there are plenty of plant-based protein food options, if you do not enjoy these or find it difficult to get enough at certain times of day (such as breakfast), then you may not be meeting your protein needs. Soy protein powder can be an easy means of boosting your protein intake.
People on-the-go. When we’re on the go, it can be hard to always get a complete meal. Soy protein powder can be a helpful resource if you need an easy, portable meal or snack. For example, you can have a well-balanced smoothie for breakfast using soy protein powder as one ingredient.
Who May Not Benefit From Soy Protein Powder?
People with an iodine deficiency. Some research shows that soy may have a negative effect on thyroid function in those with an iodine deficiency. Therefore, if you are iodine deficient, you may want to consider a different vegan protein powder option.
People who are pregnant. Pregnant individuals have higher protein needs, but there is little research on the effect of soy isoflavones on fetal health, so you may want to avoid soy protein powder until more research is available.
People who are sedentary or minimally active. If you are generally healthy, minimally active, and eat a diet that includes a good source of protein at each meal, then your protein needs are likely achievable through food alone.
People with kidney problems. Because overconsumption of protein can be taxing on the kidneys, you may want to be careful with protein powder intake if you have a kidney problem. Protein powder has high amounts of protein in a small volume, so it can be easier to exceed protein needs.
How We Selected
Our team works hard to be transparent about why we recommend certain supplements; you can read more about our dietary supplement methodology here.
We support supplements that are evidence-based and rooted in science. We value certain product attributes that we find to be associated with the highest quality products.
It's important to note that the FDA does not review dietary supplements for safety and effectiveness before they go to market. Our team of experts has created a detailed, science-backed methodology to choose the supplements we recommend.
To help come up with this list, we consulted with sports dietitian Starla Garcia, M.Ed, RDN, LD.
What to Look For
Third-Party Testing
Supplements that are third-party tested are sent to a lab where they are tested to ensure they contain what they say they contain and are not contaminated with specific high-risk, common contaminants. However, it’s important to note:
Third party testing does not test to see if a product is effective or safe for everyone, and it does not ensure the supplement will not interact with other supplements or medications.
Not all third-party testing is created equal. It is not uncommon for supplement companies to pay labs for certificates after conducting minimal to no testing.
The third party certifications we can trust are: ConsumerLab.com, NSF, and USP. However, these certifications are difficult to obtain and/or expensive for manufacturers, so many companies choose not to get their products tested by one of these three organizations.
Sometimes products tested by these three companies are more expensive to try to offset the cost they pay for certification.
Just because a supplement is not tested by one of these three companies, it does not mean it’s a bad product. We recommend doing some research on the reputability of the manufacturer, and calling up the manufacturer and their testing lab to determine their protocols and decide if you feel comfortable consuming the supplement.
Protein powders may contain trace amounts of heavy metals, especially those that are plant-based. This is likely related to plants’ uptake of heavy metals through the air, water, and soil. However, the levels found in protein powders have not been found to be harmful when consumed in moderation. Purchasing third-party tested products helps ensure the product does not contain harmful levels of heavy metals.
Form
While soy protein can be found in concentrated and hydrolyzed forms, soy protein isolate is the form used for soy protein powders. This means the protein itself has been extracted from the soybean, removing the carbohydrates and fat.
Ingredients & Potential Interactions
It is essential to carefully read the ingredient list and nutrition facts panel of a supplement to know which ingredients and how much of each ingredient is included relative to the recommended daily value of that ingredient. Please bring the supplement label to a healthcare provider to review the different ingredients contained in the supplement and any potential interactions between these ingredients and other supplements and medications you are taking.
Protein powders can contain added sweeteners, food allergens, or performance enhancers. Reading the ingredient list and purchasing third-party tested products whenever possible can help you avoid consuming a product that aggravates intolerances or contains ingredients you are allergic to.
Soy Protein Powder Dosage
Always speak with a healthcare professional before adding a supplement to your routine to ensure that the supplement is appropriate for your individual needs and to understand which dosage to take.
The Dietary Guidelines for Americans recommend that sedentary adults consume 0.8 grams of protein per kilogram of body weight each day. For a 150-pound individual, this means 55 grams of protein, and for a 200-pound individual, this means 73 grams of protein.
However, this can vary greatly based on your physical activity level, whether you are pregnant or lactating, or if you have other medical conditions that affect protein needs. For a competitive athlete, protein needs can reach 1.4 to 2 grams per kilogram of body weight, which is why protein powders can particularly benefit this population.
It is generally best to get your nutrition from a variety of sources. While soy protein powder can contribute to meeting your protein needs, you may want to regularly incorporate a variety of protein sources to ensure you get enough methionine and reap the nutritional benefits of other food sources of protein.
How Much Is Too Much?
While there is no tolerable upper limit (UL) for protein, research has shown that consuming over 2 grams per kilogram long-term can result in renal, vascular, and digestive abnormalities. Researchers have proposed an upper limit of 3.5 grams per kilogram of body weight.
There are other risks of consuming too much soy protein, which include:
Inadequate consumption of vitamin B12
Inadequate methionine consumption
Overconsumption of heavy metals
Inadequate consumption of carbohydrates and fats
Frequently Asked Questions
Is soy protein isolate harmful, especially for men?
Some may worry that soy isoflavones may alter testosterone production in men. However, research has shown this to be false, and soy protein isolate is considered safe for men to eat without experiencing feminizing effects.
How does soy protein powder compare to whey?
According to the International Society of Sport Nutrition, whey protein may be digested faster and, thereby, promote optimal muscle protein synthesis for athletes. However, because soy protein is also a complete protein, it has been shown to promote muscle protein synthesis, particularly when consumed throughout the day and especially around a workout.
A clinical trial from 2020 found no difference in lean muscle mass after a 12-week resistance training program between participants supplementing with soy protein isolate and whey protein isolate.
Because whey protein powder is made with dairy, it may contain lactose, so if you are lactose intolerant, soy protein may be a better option. Soy protein powder may also be a better option for those with a milk allergy.
Are there side effects from consuming soy protein powder?
The most common known side effects are constipation or diarrhea. Otherwise, as noted above, pregnant people may not want to consume soy protein powder. Additionally, soy isoflavones may alter thyroid function in those with an iodine deficiency, so it is recommended that they avoid soy protein.
Is soy protein gluten-free?
Soy protein in and of itself is gluten-free. Gluten is only found in wheat, barley, and rye. However, soy protein powders could contain other ingredients with gluten or be contaminated with gluten if made in a facility that processes other gluten-containing products. If you have celiac disease, it is important to verify that the product is certified gluten-free before purchasing. We recommend Bob’s Red Mill Soy Protein Powder if you want a certified gluten-free option.
What are some recipes I can use soy protein powder in?
Soy protein powder can make a great addition to smoothies, milkshakes, oatmeal, pancakes, or even some baked goods. Here are some creative ideas for how to use protein powder.
Read Next: The Best Vegan Multivitamins & Supplements of 2023
