The protein powder market offers consumers an extensive array of options. Beyond choosing from countless companies and brands, you must decide between various protein sources — including whey, casein, pea, egg white, soy, rice, hemp, and many more.
Since each protein type offers distinct advantages and drawbacks, understanding these differences simplifies shopping for the ideal product.
This post explores one of today’s most prominent protein sources — soy protein. Let’s dive in!
What Is Soy Protein Powder?
As the name suggests, soy protein powder derives from soybeans. These legumes provide high-protein, low-fat, and low-carb nutrition, making them an excellent foundation for protein powder.
Many people express reservations about soy protein, typically citing two primary concerns.
First, they worry about phytates — also known as antinutrients. These compounds in soy protein reduce iron and zinc availability. While this presents a potential drawback, adverse effects only occur in individuals relying on soy protein powder for iron and zinc intake.
Iron and zinc are readily available in meat, dairy, eggs, legumes, nuts, and seeds. Since most people don’t depend on protein shakes for daily iron and zinc requirements, antinutrients rarely pose a significant issue.
Second, people express concern about isoflavones and phytoestrogens. Isoflavones function as goitrogens, potentially interfering with hormone production and thyroid function. Meanwhile, phytoestrogens might affect estrogen production.
However, research fails to substantiate claims about soy protein negatively impacting thyroid function. Additionally, soybeans undergo water and alcohol processing, which eliminates the majority of phytoestrogen content.
Despite persistent concerns surrounding soy protein, scientific evidence continues disproving these worries.
How nutritious is soy protein?
As mentioned previously, soy protein delivers exceptional nutrition by providing beneficial nutrients while minimizing unwanted components.
A 28-gram (one ounce) serving of soy protein powder provides:
| Category | Per Serving | %DV |
| Calories | 95 | 5% |
| Protein | 23 g | 46% |
| Total Carbs | 2.1 g | 1% |
| Total Fat | 0.9 g | 1% |
| Fiber | 1.6 g | 6% |
| Vitamin B9 | 49 mcg | 12% |
| Iron | 4.1 mg | 23% |
| Phosphorus | 217 mg | 22% |
| Copper | 0.4 mg | 22% |
| Manganese | 0.4 mg | 21% |
| Sodium | 281 mg | 12% |
The table demonstrates substantial protein content per serving while avoiding excessive calories, carbs, and fats typically found in everyday foods.
Beyond high levels of Iron, Phosphorus, Copper, and Manganese, soy protein powder contains modest amounts of Calcium (5%), Magnesium (3%), and Zinc (8%).
Is soy protein a complete protein?
When selecting soy protein powder, ensure you choose a complete protein. Not all protein powders offer equal benefits, and some deliver superior nutritional value.
A complete protein contains all nine essential amino acids — those your body cannot produce independently. These nine essential amino acids are: Phenylalanine, Tryptophan, Valine, Leucine, Isoleucine, Threonine, Methionine, Lysine, and Histidine.
Unlike most plant-based proteins, soy protein contains all essential amino acids — though certain ones appear in lower concentrations. Here’s a detailed breakdown of amino acid content in soy protein powder (including non-essential ones):
| Amino Acid | Percentage of Total AA | mg/100-gram serving |
| Alanine | 4.3% | 2,677 mg |
| Arginine | 7.4% | 4,642 mg |
| Aspartic Acid | 11.5% | 7,249 mg |
| Cystine | 1.4% | 886 mg |
| Glutamic Acid | 19.1% | 12,013 mg |
| Glycine | 4.3% | 2,688 mg |
| Histidine | 2.5% | 1,578 mg |
| Isoleucine | 4.7% | 2,942 mg |
| Leucine | 7.8% | 4,917 mg |
| Lysine | 6.2% | 3,929 mg |
| Methionine | 1.3% | 814 mg |
| Phenylalanine | 5.2% | 3,278 mg |
| Proline | 5.2% | 3,298 mg |
| Serine | 5.4% | 3,369 mg |
| Threonine | 3.9% | 2,474 mg |
| Tryptophan | 1.3% | 835 mg |
| Tyrosine | 3.7% | 2,301 mg |
| Valine | 4.9% | 3,064 mg |
What are the benefits of soy protein powders?
We’ve explored soy protein’s nutritional advantages, but let’s examine how these benefits impact your health. First, let’s recap what we’ve learned about soy protein.
Soy protein is a plant-based, complete protein that’s high in protein while remaining low in calories, fat, carbs, and cholesterol. It also delivers substantial amounts of iron, phosphorus, copper, and manganese.
Thanks to abundant BCAAs, soy protein powders rank as the premier plant-based option for muscle growth and repair. This category is typically dominated by whey and casein proteins, both animal-derived.
Essentially, soy protein delivers animal-based benefits from a plant-based source.
Research also demonstrates soy protein’s effectiveness matching animal-based proteins for weight loss, further cementing its plant-based superiority.
How To Choose The Best Soy Protein Powder
Multiple factors influence your soy protein powder selection. Without careful consideration, daily protein shakes could negatively impact your health.
Key considerations include taste, nutrition facts, price, dietary restrictions, and whether it combines with other protein types. We’ll examine each factor below.
Taste
Soybean flavor doesn’t appeal to everyone, but you needn’t enjoy raw soybean taste to appreciate soy protein shakes. Many brands offer various flavors to mask any unwanted taste.
While chocolate and vanilla remain most popular, some brands create unique, creative flavor options. They typically offer natural flavor for those who appreciate soy’s natural taste.
Choose a company offering flavors that appeal to your preferences.
Nutrition Facts
While we’ve discussed soy’s nutritional benefits, some companies compromise their powder by adding unnecessary or potentially harmful ingredients. The nutrition facts we listed earlier excluded these additives, so don’t assume all soy protein powders are identical.
Seek three key elements in soy protein powder: abundant protein, minimal carbs or fat, and a solid vitamin and mineral profile.
Price
Soy protein powder ranges from $10 to $50 and beyond. Like most products, you typically get what you pay for. However, not everyone requires identical strength or protein content.
Before shopping, define your goals and desired nutrient levels. Your spending will largely depend on these factors.
Dietary Restrictions
Soy protein powder works excellently for those with lactose intolerance, dairy allergies, vegans, and vegetarians. However, soy allergies exist and should preclude consumption.
Always check ingredient labels before purchasing. As mentioned, many brands add ingredients that could compromise vegan-friendliness or dairy-free status.
Is It Combined With Other Protein?
Whey and casein proteins rarely mix with other protein types since they’re already complete proteins requiring no enhancement. Plant-based protein powders differ.
Though soy protein is complete, it’s often combined with rice, hemp, and pea proteins. This isn’t necessarily problematic, but check labels if you prefer exclusively soy protein.
Best Soy Protein Powders
Now that we’ve covered everything about soy protein powders, let’s find one that suits your needs.
To simplify your search, we’re sharing four favorite soy protein powders available today.
Let’s explore our top choices and their standout features!
Soy Protein Powder by Bob’s Red Mill
We’ll start with the most affordable option, which also offers the lowest protein content. Nevertheless, this product excels for anyone seeking modest yet effective nutritional enhancement. Each 20-gram serving delivers 17 grams of protein with only 80 calories.
A 20-serving bag costs under $10, though you can purchase 25-pound bags for $171 if you want substantial supply (likely over a year’s worth).
GET THE BEST PRICE ON BOB’S RED MILL SOY PROTEIN POWDERSoy Protein Isolate Powder by Puritan’s Pride
Puritan’s Pride offers a soy protein isolate that delivers more potency per shake. Each 28-gram serving provides 24 grams of protein and 110 calories, plus healthy amounts of iron and phosphorus.
Available in natural, vanilla, and chocolate flavors, each tub contains approximately 32 servings. Though normally $37, their current 50% promotion reduces the price to under $20 — excellent value for powerful protein powder.
GET THE BEST PRICE ON PURITAN’S PRIDE SOY PROTEIN ISOLATE POWDERSoy Protein Isolate by MyVegan
This represents my top choice from this list. It features larger 30-gram servings containing slightly more protein than Puritan’s Pride — 25 grams per serving. It provides 110 calories plus over 20% DV of both calcium and iron.
MyVegan offers chocolate, vanilla, and unflavored options. Each bag contains about 33 servings for $40 normally, though their current 50% promotion brings it down to $20.
GET THE BEST PRICE ON MYVEGAN SOY PROTEIN ISOLATESoy Protein Isolate by NOW Sports
We’ve saved this option for last because it contains the highest calorie count with respectable protein levels, making it ideal for frequent exercisers. Each roughly 45-gram serving creates substantial shakes.
Each serving contains 25 grams of protein and 160 calories, with high amounts of iron and BCAAs supporting muscle growth and recovery. A 2-pound tub with approximately 40 servings costs just under $36 for chocolate and vanilla flavors. Their unflavored option costs less but contains fewer calories and protein.
GET THE BEST PRICE ON NOW SPORTS SOY PROTEIN ISOLATE
