Soy-Free Protein Powder Guide

Soybeans are an increasingly popular food item, particularly in the United States. As production goes up, it’s more common to find soy in many different food items, including protein powder.

But not everybody likes soy. Some of its opponents claim that it can cause an imbalance in hormones. While soy is a complete source of protein, some people choose to stay away from it because of these claims. As such, many health and fitness enthusiast only take soy-free protein powder.

We’ve scoured the market to find the best soy-free protein powders for you. We’ve also summarized the soy debate further down.

In this guide:

• The top 12 soy-free protein powders
• A summary of the soy health debate
• Ideal protein intake for different goals
• The benefits of supplementing protein

Top 12 Best Soy-Free Protein Powders

---

Why Go Soy-Free?

A summary on the soy debate.

Whether soy is good or bad for you is hotly debated. While there’s no question over whether soy is a complete source of protein, some sources claim that soy can be harmful to health.

Arguments Against Soy

Most notably, there is debate over whether soy has an impact on factors related masculinity.

Opponents of soy usually make some or all of the following claims:

• “Soy reduces testosterone”
• “Soy boosts estrogen levels”
• “Soy decreases fertility”

The line of reasoning for these arguments is usually as follows:

Soybeans contain phytoestrogens. Phytoestrogens are a class of a plant-derived chemicals that mimic certain aspects of estrogen.

Most notably, certain phytoestrogens can bind to estrogen receptors in the body, potentially impacting hormonal balance.

Soybeans contain a class of phytoestrogens called isoflavones. Specifically, soybeans primarily contain the isoflavones daidzein and genistein, which both have the potential to bind to estrogen receptors in the body.

Opponents of soy claim that when the soybean’s phytoestrogen isoflavones bind to estrogen receptors, levels of estrogen rise in the body. In men, high levels of estrogen can lead to infertility, erectile dysfunction, decreased sex drive, and gynecomastia—breast tissue growth.

Biochemically, this could theoretically happen. However, such a theory needs scientific testing. Opponents of soy point to the following studies:

1. One study followed a 19-year-old diabetic male.¹Hypogonadism and erectile dysfunction associated with soy product consumption. To examine the effects of soy, the subject began eating large amounts of soy-based products on a vegan diet. He experienced a significant decrease in testosterone and libido, which persisted until one year after ceasing his soy-heavy vegan diet.

2. Another study examined the eating habits of 99 men in subfertile couples (meaning they were unable to or were having difficulty with conceiving).²Soy food and isoflavone intake in relation to semen quality parameters among men from an infertility clinic The study found a correlation between soy intake and lower sperm count. This was most notable at very high levels of soy intake.

3. One study examined the effects of soy protein isolate in 35 men.³Soy protein isolates of varying isoflavone content exert minor effects on serum reproductive hormones in healthy young men. They consumed milk protein isolate, low-isoflavone soy isolate, and high-isoflavone soy isolate for 57 days each. The researchers noted a decrease in testosterone after consuming both soy isolate products.

This research, at face value, suggests that soy products may negatively impact fertility, testosterone, and other masculine traits. However, as we discuss below, most research on soy does not support the above findings.

Arguments in Favor of Soy

Those who argue in favor of soy products will point out the flaws in the above studies. Furthermore, they argue that the vast majority of research has not found any correlation between soy consumption and hormonal imbalance.

First, there are several issues with the above studies.

1. There are a number of factors associated with the study on this 19 year old male that make it difficult to generalize the findings. First of all, he was diabetic. Secondly, he switched from an omnivorous diet to a vegan one. Finally, his low-T symptoms persisted for a year after discontinuing the diet. As such, it’s a stretch to claim that his diet was entirely the cause. And these are only a few of many factors that muddy the findings. Without any other subjects, there are no variables to control.

2. The second study similarly has several issues. Most notably, subfertile men don’t represent the general population. Other hormonal issues may already be at play. In addition, researchers only noted significantly decreased testosterone levels in those with very soy-heavy diet. Since vegans are more likely to engage in soy-heavy diets, and since the researchers did not account for vegan diets, significant dietary factors beyond soy intake alone could be at play.

3. The third study’s primary shortcoming is its very small sample size. Thousands of other factors could be at play, including the source of the soy products.

While some of these individuals studies may seem to suggest that there is a correlation between soy intake alone and hormonal imbalance, its very easy to point out their flaws.

There are a few criteria that need to be met before soy can be seriously considered as a threat to testosterone levels.

• Larger Sample Sizes

The findings thus far that have suggested that soy may decrease testosterone have only been seen in small samples. To control for age, race, diet, weight, physical activity, lifestyle, and thousands of other factors, much larger samples are needed.

It may also be that certain soy crops actually have had an impact on testosterone levels. With roughly 90 billion acres of soybean crops grown in the United States alone, any given soy product could be sourced from a wide variety of places.⁴Soybean Highlights A small sample size could end up consuming a soy product with findings that don’t represent the industry as a whole.

In addition to there being a wide varieties of crops, there are a wide varieties of soy preparations. From soy milk to tofu to silken tofu to fermented soy, there are many factors that come into play when considering the processing of these foods. Larger samples with more preparations are needed before coming to broad conclusions on soy in general.

• Repeatability

Studies suggesting that soy intake decreases testosterone have widely not been repeated with similar findings. On the other hand, studies finding little to no correlation between soy intake and testosterone have widely been supported by other studies.

Back to Phytoestrogens

Finally, we return to the original anti-soy argument: that soy contains phytoestrogens, which in turn impact hormonal balance.

As discussed above, it is true that soy contains phytoestrogens. However, the body of research has not found that the levels of phytoestrogens found in plant-based foods is enough to notably decrease testosterone. In fact, one meta-analysis of many studies found no correlation between phytoestrogens and feminization.⁵Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence.

Furthermore, proponents of soy will point out that many plant-based foods other than soy also contain phytoestrogens.

Foods high in phytoestrogens:

• Almonds
• Apples
• Beer
• Broccoli
• Carrots
• Coffee
• Grapes
• Lentils
• Oats
• Oranges
• Red wine
• Walnuts

If someone chooses to abstain from soy because of its phytoestrogen content, then they would logically also want to abstain from the above foods⁠—and many more.

Some people simply don’t like soy, and that’s fine. Some people don’t care for it and would rather avoid any potential feminization risk “just to be safe.” Perhaps that’s fine as well.

Although the body of research thus far has not found that soy negatively impacts hormonal balance, some people still prefer to stick with soy-free products. That’s why we’ve compiled this list of the best soy-free protein powders.

And if you’re fine with soy, these top picks are still excellent choices.

---

How to Take Soy-Free Protein Powder

Once you’ve decided on the best soy-free protein powder for your particular needs, you’ll want to know how much to take and when to take it. Here’s some helpful information on the ideal dosage for your soy-free protein shakes.

How Much Soy-Free Protein to Take

When to Take Your Soy-Free Protein

For more information the best dosage and timing for soy-free protein powder, check out our protein powder guide.

---

Brief Protein Overview

Not sure whether protein powders are for you? Here’s a brief overview on protein itself to help you make an informed decision.

What Are Proteins?

Proteins are made up of amino acids, the building blocks of the entire body. They’re used for all sorts of structures throughout the body, from building muscle tissue to tendons. They also play other important roles in many bodily functions.

There are 20 total amino acids. Eight of these, called essential amino acids, cannot be produced by the body and must come from diet. (There 9 essential amino acids for infants.)

Complete proteins contain all 8 essential amino acids, and incomplete proteins don’t. Most animal food sources are complete, and most plant food sources are incomplete. There are exceptions to both rules, of course.

Benefits of Protein Supplements

The following information is summarized from our complete protein powder guide. Give it a read for more thorough information.

Athletics

Weight Loss

Research has demonstrated that drinking protein shakes can help with reducing fat mass while increasing or maintaining muscle mass.³⁵Whey Protein Supplementation Improves Body Composition and Cardiovascular Risk Factors in Overweight and Obese Patients: A Systematic Review and Meta-Analysis³⁶A whey-protein supplement increases fat loss and spares lean muscle in obese subjects: a randomized human clinical study³⁷Effects of protein supplements consumed with meals, versus between meals, on resistance training–induced body composition changes in adults: a systematic review

There are a few contributing factors here. The simplest is that protein shakes are filling, and can often replace unhealthy food choices. They can help with both appetite control and responsible dietary choices.

But beyond simple meal replacements, protein shakes help increase muscle mass, which in turns helps with burning fat.

Even at rest, muscle consumes more calories than fat does. This means that the more muscle tissue you have, the higher your resting metabolism. And the higher your resting metabolism, the easier it is to maintain a calorie deficit and burn fat.

---

Summary

Protein powders can be a great source of nutrition and a great way to hit fitness goals. Luckily, for those who are trying to avoid soy, there are lots of soy-free protein powders on the market.

For more information on protein supplementation, see our complete protein powder guide.