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Soybeans have long been considered a nutrient-dense protein source for vegetarians and vegans, making them a popular base for plant-based protein powders. With long ingredient lists and vague performance claims, however, trying to read the labels on protein supplements can be confusing. This can make your search for the best soy protein powder challenging, to say the least.

Here, the soy protein isolate from Bulk Supplements is a breath of fresh air. But is its ingredient list too simple? Is it still helpful for bulking up, losing body fat, and meeting your protein goals? 

In our Bulk Supplements Soy Protein Isolate review, we explain everything you need to know about this popular protein so you can decide whether it’s right for you. 

Medical disclaimer: This article is intended for educational and informational purposes only. It is not intended as a substitute for medical advice. For health advice, contact a licensed healthcare provider. GGR also recommends choosing a product that has been third-party tested for quality.

Protein Reviews From Nutrition Experts

Not sure what to look for in a protein powder? Leave it to our expert team of strength and conditioning coaches, registered dietitians, certified personal trainers, certified nutrition coaches, and Olympic athletes! As protein aficionados, we love putting protein powders to the test to help you find the right one for your needs.

Our testers assess a series of factors on a scale of 1 to 5 when testing protein supplements, including:

  • Price
  • Formulation
  • Taste
  • Solubility
  • Side effects
  • Third-party testing
  • Customer service

And to see whether each protein really meets the needs of active individuals, we test them as part of our normal fitness routines.

Bulk Supplements Soy Protein Isolate

Bulk Supplements Soy Protein Powder

GGR Score: 4.45 starstarstarstarstar

Product Highlights

  • Soy protein powder
  • Manufactured in FDA-registered and inspected facility
  • Unflavored

Pros & Cons

Pros

  • Cheap at $0.82 per serving
  • Third party-tested
  • Unflavored

Cons

  • Makes mess when you open bag
  • Customers state doesn’t blend well
  • Doesn’t come with a scoop

Bottom Line

Bulk Supplements Soy Protein Powder is a cheap vegan protein option, but reviewers share it isn’t the best-tasting option.

A Quick Look at Bulk Supplements Soy Protein Isolate

For anyone interested in simple, affordable protein powders without unnecessary ingredients, it’s hard to beat Bulk Supplements. They use soy protein isolate as the one and only ingredient in this protein powder.

Because of this, it’s a very lean, low-calorie protein that supports a variety of health and fitness goals. 

Before You Buy

  • Available in a variety of bulk sizes
  • Unflavored and unsweetened
  • Doesn’t come with a scoop, so it may be difficult to measure precisely 

Is Bulk Supplements Soy Protein Isolate Worth It?

Soy protein is the only ingredient in this supplement, providing 25 grams of complete plant protein per serving and nothing you don’t need. Considering the amount of protein you get for such an affordable price ($0.75 per serving), we think it’s well worth the money. 

Looking down into a bag of Bulk Supplements Soy Protein Isolate.

Of course, with only one ingredient, it’s unflavored and unsweetened. It may not taste as good as other proteins on its own, but this is what makes it versatile. It also means this soy protein isolate powder is free from additives and artificial sweeteners.

Great for:

  • Anyone wanting to build muscle and support muscle recovery with plant protein
  • Bodybuilders and others who need a high-protein, low-calorie product
  • Those on a budget

Not recommended for:

  • Those who prefer flavored or sweetened protein powders
  • Anyone in a bulking phase with higher calorie needs
  • Individuals with soy allergies

Bulk Supplements Soy Protein Isolate Specs

Price per serving$0.75
Serving size30 g (about 4 Tbsp)
FlavorsUnflavored
Protein sourceSoy protein isolate
Calories per serving90
Protein per serving25 g
Carbs per serving4 g (3 g dietary fiber)
Fat per serving0 g
Other notable ingredientsNone
Third-party tested?Yes

Experience Using Bulk Supplements Soy Protein Isolate

Anthony O’Reilly, GGR performance editor and certified nutrition coach, was happy to use his professional expertise in protein supplements to test the Bulk Supplements Soy Protein Isolate for us.

A woman holds up a scoop of Bulk Supplements Soy Protein Isolate next to a shaker glass of water.

This protein is unflavored, making it a really versatile supplement. To get a feel for its best uses, Anthony tried a scoop of this protein mixed with water, milk, and blended into a smoothie. “In my opinion, this protein tastes the best when added to a fruit smoothie. It’s quite plain and boring on its own. However, the price per serving is outstanding.”

RELATED: Protein Smoothie Recipes

Price Per Serving

Bulk Supplements sells its products in bulk (no surprise there) and uses simple, no-frills ingredients to keep costs low while still providing high-quality products. At $0.75 per 25-gram protein serving, it’s tough to beat this budget-friendly soy protein. 

You can bring the cost down even more by using their Subscribe & Save option, which saves you 10% on recurring orders.

Formulation

With one simple ingredient and 25 grams of high-quality plant protein per serving, Bulk Supplements hit it out of the park with their soy protein isolate. As a protein isolate, this product is higher in protein and lower in fats and carbs than protein concentrates, making it a great choice for strict calorie or macro needs.

Additionally, soy is a complete protein containing all nine essential amino acids in optimal proportions for overall health and muscle maintenance. 

Its protein content includes all three branched-chain amino acids (BCAAs), including 1.6 grams of leucine per serving.

One serving of this protein falls well within the 20 to 40 grams of protein per meal as recommended by the International Society of Sports Nutrition1 for stimulating muscle protein synthesis and building muscle. If desired, you can easily bump the protein up to 33 grams by making a post-workout shake with a cup of soy milk.

Interestingly, it isn’t as high in calcium as whey protein isolate powder, but does contain more potassium and iron.

RELATED: Best Whey Protein

Taste and Solubility 

If you’re looking for a protein powder that tastes amazing mixed with water or milk, you’ll probably be disappointed. “This protein is unflavored and definitely tastes plain,” said Anthony. 

Customer reviews are pretty mixed on the flavor. However, since we thought it was mild enough to blend well with other flavors in a smoothie, we rated it a 4 out of 5 for taste.

A woman holds up a shaker glass of Bulk Supplements Soy Protein.

It got the same score for solubility, with Anthony reporting that, “It blends fairly smoothly, though it’s hard to measure each scoop precisely since there’s no scoop included.”

Side Effects

If you need a protein powder for sensitive stomachs, this soy protein could be a great option. Plant protein powders like soy and pea protein are usually better tolerated than whey since they don’t contain lactose. This soy protein is also free from sugar alcohols and natural sweeteners like stevia, which some people find bothersome.

Based on his testing results, Anthony gave this product a 5 out of 5 rating for its lack of gastrointestinal side effects. 

RELATED: Are There High-Protein Diet Side Effects? 

Third-Party Testing 

Bulk Supplements doesn’t mention third-party testing on the product label or webpage for this specific protein, but their website states that all products are third-party tested. Disappointingly, they don’t name the specific labs that they use. 

That said, the brand does offer Certificates of Analysis upon request. Because we’d prefer a bit more transparency, we rated them a 3 out of 5 here.

Bulk Supplements Soy Protein Isolate vs Bob’s Red Mill Soy Protein 

Bob’s Red Mill Soy Protein

Bob’s Red Mill Soy Protein

GGR Score: 4 starstarstarstarstar

Product Highlights

  • Soy protein powder
  • Vegan- and Keto-friendly
  • Gluten-free
  • Unflavored formula 
  • 17 g of protein per serving
  • 70 calories

Pros & Cons

Pros

  • Contains two ingredients
  • Good for baking
  • Ideal for low-calorie diets

Cons

  • Some customers say it’s gritty
  • Almost $2 per serving
  • No flavors

Bottom Line

Bob’s Red Mill Soy Protein is ideal for vegans looking for a soy protein isolate. This unflavored protein powder can be used in smoothies, oatmeal, baked goods, or pancakes. It provides 17 grams of protein per serving and only 1 gram of fat and carbohydrates per serving.

To get a feel for how the Bulk Supplements Soy Protein Isolate stacks up to similar products, we’ve compared it directly to Bob’s Red Mill Soy Protein in the table below. Like Bulk Supplements, Bob’s Red Mill is beloved for its simple, high-quality foods and dietary supplements. It does, however, cost more per serving than the Bulk Supplements Soy Protein and it also has less protein per serving.

Bulk Supplements Soy Protein IsolateBob’s Red Mill Soy Protein
Price per serving$0.75$1.96
Serving size30 g (about 4 Tbsp)¼ cup (20 g)
FlavorsUnflavoredUnflavored
Protein sourceSoy protein isolateIsolated soy protein
Calories per serving9080
Protein per serving25 g17 g
Carbs per serving4 g (3 g dietary fiber)0 g
Fat per serving0 g1 g
Other notable ingredientsNoneNone
Third-party tested?YesNo

Customer Experience 

Based on their website and customer reviews, Bulk Supplements appears to offer top-notch customer service. The ordering and delivery process was seamless, so we never needed to contact them ourselves. If you need to do so, they offer customer service via live chat, phone, and email seven days a week. 

You can return items within 30 days of purchase regardless of whether they’ve been opened, although you may receive a smaller refund for opened containers.

Ordering Bulk Supplements Soy Protein Isolate

Ordering from Bulk Supplements is as easy as it gets. All you need to do is choose which size bag you want, select your preferred delivery frequency, and add the product to your virtual cart. 

The Subscribe & Save offer allows you to choose from automatic deliveries every 1 to 6 months, which is a great option if you love the product.

Economy shipping to Texas, where I live, was $9.95, with standard shipping priced at $12.95. Fortunately, Bulk Supplements has a free shipping offer with orders over $59.

Customer Reviews

Most customer reviews we found are positive, with a 4.7-star rating on bulksupplements.com. Many like how mild the flavor is, saying it mixes well with stronger flavors and has good solubility even in cold liquids.

That said, some enjoyed the consistency but thought the flavor was too strong to overlook. Others loved the eco-friendly packaging.

Reviews are more mixed on Amazon, with a 4-star rating from over 1,000 reviews. Most people say it’s enjoyable as long as you blend it with more flavorful ingredients and don’t expect it to taste amazing on its own. Everyone has different tastes, of course, and a few customers found it clumpy, thick, and unpleasant tasting.

Based on these reviews, it might be best blended rather than mixed or shaken.

Final Verdict of Our Bulk Supplements Soy Protein Isolate Review

Overall, this is a fantastic option for anyone wanting a high-quality soy protein powder without the unnecessary bells and whistles. It’s a great value for the price and is effective for building muscle and strength or preventing the loss of muscle mass during a weight-loss phase. 

RELATED: Best Protein Powder for Weight Loss

That said, as an unflavored protein, most people will enjoy it best when blended in a smoothie with strong flavors like fruit, chocolate, or nut butter.

In summary, we had the following takeaways after testing this soy protein:

  • High-quality protein source with 25 g per serving
  • Requires a kitchen scale for accurate measuring
  • Mild flavor is easily disguised in smoothies and protein shakes
  • No artificial ingredients or sweeteners
  • Well-tolerated and easy to digest

It’s good, but is it the best protein for plant-based diets? Check out whether this soy protein made the cut for the Best Vegan Protein Powder!

Full Rating

Bulk Supplements Soy Protein Isolate

Bulk Supplements Soy Protein Powder is a cheap vegan protein option, but reviewers share it isn’t the best-tasting option.

Product Brand: Bulk Supplements

Product Currency: $

Product Price: 14

Product In-Stock: InStock

Editor's Rating:
4.45

Bulk Supplements Soy Protein Isolate Rating

Price per serving – 5
Formulation – 5
Taste – 4
Solubility – 4
Side effects – 5
Third-party testing – 3
Customer service – 5
Customer reviews – 4.6
Buy Now

Bulk Supplements Soy Protein Isolate: FAQs

Is soy protein isolate good or bad for you?

Soy protein isolate is a healthy choice for increasing your protein intake. As a high-quality protein, it’s effective for building muscle or losing weight. It’s also been shown to have anti-inflammatory benefits2 in older adults, likely due in part to its isoflavone content.

Can you build muscle with soy protein isolate?

Yes! As long as total daily protein intake is adequate, soy protein isolate is equally as effective3 as whey protein isolate for building muscle size and strength. A 12-week randomized controlled trial4 saw similar results when whey and soy protein were matched for leucine content.

Which is better, soy protein isolate or whey protein isolate?

Soy protein isolate and whey protein isolate are both high-quality, complete proteins. Ultimately, the choice is up to your personal preference. 

Does soy protein isolate increase estrogen?

There’s no strong evidence in humans that soy protein isolate raises estrogen levels. Soy foods contain isoflavones which are similar in structure to human estrogen, but can have different effects. Recent research suggests that soy protein doesn’t increase estrogen5.

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any diseases.

References

  1. Jäger, R., Kerksick, C. M., Campbell, B. I., Cribb, P. J., Wells, S. D., Skwiat, T. M., Purpura, M., Ziegenfuss, T. N., Ferrando, A. A., Arent, S. M., Smith-Ryan, A. E., Stout, J. R., Arciero, P. J., Ormsbee, M. J., Taylor, L. W., Wilborn, C. D., Kalman, D. S., Kreider, R. B., Willoughby, D. S., Hoffman, J. R., … Antonio, J. (2017). International Society of Sports Nutrition Position Stand: protein and exercise. Journal of the International Society of Sports Nutrition, 14, 20. https://doi.org/10.1186/s12970-017-0177-8
  2. Prokopidis, K., Mazidi, M., Sankaranarayanan, R., Tajik, B., McArdle, A., & Isanejad, M. (2023). Effects of whey and soy protein supplementation on inflammatory cytokines in older adults: a systematic review and meta-analysis. The British Journal of Nutrition, 129(5), 759–770. https://doi.org/10.1017/S0007114522001787
  3. Hevia-Larraín, V., Gualano, B., Longobardi, I., Gil, S., Fernandes, A. L., Costa, L. A. R., Pereira, R. M. R., Artioli, G. G., Phillips, S. M., & Roschel, H. (2021). High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores. Sports Medicine (Auckland, N.Z.), 51(6), 1317–1330. https://doi.org/10.1007/s40279-021-01434-9
  4. Lynch, H. M., Buman, M. P., Dickinson, J. M., Ransdell, L. B., Johnston, C. S., & Wharton, C. M. (2020). No Significant Differences in Muscle Growth and Strength Development When Consuming Soy and Whey Protein Supplements Matched for Leucine Following a 12 Week Resistance Training Program in Men and Women: A Randomized Trial. International Journal of Environmental Research and Public Health, 17(11), 3871. https://doi.org/10.3390/ijerph17113871
  5. Haun, C. T., Mobley, C. B., Vann, C. G., Romero, M. A., Roberson, P. A., Mumford, P. W., Kephart, W. C., Healy, J. C., Patel, R. K., Osburn, S. C., Beck, D. T., Arnold, R. D., Nie, B., Lockwood, C. M., & Roberts, M. D. (2018). Soy protein supplementation is not androgenic or estrogenic in college-aged men when combined with resistance exercise training. Scientific Reports, 8(1), 11151. https://doi.org/10.1038/s41598-018-29591-4

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