Guide to Soy Protein Powder for Bodybuilding

With the surge of veganism and plant-based dieting, plant-based proteins have become a household name in the fitness industry.

That said, we wanted to present you with a complete guide to soy protein powder for bodybuilding, so you can make the best decision for you and your body.

What is Soy Protein Powder?

Soy protein powder is a plant-based protein powder derived from soybeans. As with most plant-based proteins, it’s low in fat and cholesterol while providing you with a solid source of dietary fiber.

Soy protein powder is considered a complete protein, meaning it contains all 9 essential amino acids that our bodies need for optimal health and bodybuilding.

One thing to note, however, is that while soy protein may be a complete protein, its amino acid profile will greatly vary depending on the strain of soy used to manufacture the protein powder. That said, most of the time, you will get a sufficient amount of each essential amino acid to support muscle growth and recovery. [1]

What are the Benefits of Using a Soy-Based Protein Powder?

There are more than a handful of benefits coming from soy-based protein powders. Here are a few:

Muscle Building Properties

Soy protein powder, more precisely soy protein isolate, is a rich source of protein, providing around 80-85% protein by weight. This is enough to go toe-to-toe with various animal-based proteins, such as whey and egg. That, coupled with a very good amino acid profile, makes soy protein powder an excellent choice for bodybuilding.

Aids in Weight Loss

The evidence is mounting – soy protein and its isoflavones may be a game changer in the fight against obesity. Studies show that consuming soy protein can result in weight loss, as well as decreased levels of cholesterol and triglycerides. However, it’s important to note that just consuming soy protein itself won’t amount to much unless you are performing regular exercise and following a caloric deficit diet.

Good for Overall Health

Soy protein powder can lower cholesterol levels and improve heart health. [2] As a result, it may help lower blood pressure and reduce the risk of heart disease.

Additionally, research suggests soy protein may have anti-cancer properties, particularly for prostate cancer. [3]

Improves Bone Health

Soy protein powder may improve bone health by reducing the risk of osteoporosis and increasing bone density. [4]

As you can imagine, strong bones are incredibly beneficial for bodybuilding, as it helps to lower the risk of injury, which could significantly derail your progress.

Is Soy Protein Good for You?

Yes, soy protein is good for you.

That said, it should be noted that supplementing with soy protein powder is not a substitute for healthy lifestyle choices.

While it can provide you with a slew of benefits, such as increased muscle mass and improved bone health, soy protein powder is not a magical powder that could offset the detrimental effects of poor dieting, a sedentary lifestyle, or low-quality sleep.

Does Soy Protein Have Any Side Effects?

Soy protein powder is generally considered to be very safe if consumed in the recommended amounts. That said, there are some side effects commonly associated with soy products, including soy protein powder.

Digestive Issues

Despite its PDCAAS being 1.0, some people may experience gas, bloating, or diarrhea when consuming soy protein powder or other soy-based products.


Soy protein can be highly allergenic, provoking various unpleasant symptoms in sufferers: hives, itching, swelling, and even difficulty breathing. If you think soy may be causing your discomfort, it’s important to consult with an allergist as soon as possible for appropriate diagnosis and treatment.

Reduced Absorption of Minerals

Studies have suggested that soy protein may block the absorption of minerals such as zinc, iron, and calcium. [5] However, additional research is needed to know the extent to which this occurs and how detrimental it could be.

Why Might Someone Choose Soy Protein Over Whey?

The main reason someone would choose soy over whey protein is due to dietary or lifestyle restrictions.

For instance, vegans would likely opt for soy protein as whey is derived from dairy products. Similarly, some people may be lactose intolerant or have a dairy allergy, so soy protein would be the better choice.

That said, whey isolate protein powders are lactose-free, so whey would still remain the better option if that is the only issue.

Is Soy Protein a Good Alternative to Whey?

It is generally considered that soy protein is the best plant-based alternative to whey protein.

Looking at the amino acid profile, soy protein powder provides a good amount of leucine and other essential amino acids that are necessary for muscle growth, making it a suitable replacement for whey.

Best Soy Protein Powders 

If you’d like to give soy protein powder a try, these three could be a good choice:

Now Soy Protein

NOW Sports Soy Protein Isolate

Coming in three different flavors with 20 grams of pure protein per scoop, Now Sport’s soy protein isolate is one of the best bangs for the buck on the market. Each scoop is only 90 calories and will set you back around $0.60 per serving while easily satisfying your protein goals.

Bulk Supplements Soy Protein

Bulk Supplements Soy Protein Isolate

Bulk Supplements’ soy protein is one of the market’s most “potent” soy protein powders, with each scoop containing 27 grams of pure protein. The only reason this isn’t our first pick is the price, as it is nearly three times more expensive per scoop than the one above.

Nutricost Soy Protein

Nutricost Soy Protein Powder

Finally, we have Nutricost Soy Protein powder, widely famed for its flavor and cost. However, with only 10 grams of protein per scoop, it’s hard to put this one above the rest, but if you’re someone that enjoys a great-tasting product – this one could be a great choice.


As you can see, soy protein powder is a great plant-based protein and a suitable option for anyone looking to increase their daily protein intake without consuming a ton of food.

It is a complete protein with a sound amino acid profile for a plant-based product, and there’s no doubt in our mind that it will help you reach your goals – whatever they might be.

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