Muscle Mass

Soy Protein Isolation - Benefits, How to Take and Tips

Protein is a fundamental nutrient in the diet of those who exercise because it is necessary for both the growth and regeneration and maintenance of various tissues, including muscle.

Although the main sources of high biological value protein are of animal origin, soy provides the best protein among vegetables, and studies indicate that regular consumption of soy protein isolate may help in hypertrophy muscular.

What is

Like other leguminous plants (a group that also includes beans and lentils), soybeans are a plant with a high protein content. Unlike them, however, soy provides a complete protein, that is, with all the amino acids that the body needs for its metabolic functions (such as muscle growth).

Protein isolated from soy, or PIS, is nothing more than a product obtained from the removal of soy fats. PIS contains at least 90% protein in its composition, and a very low content of carbohydrates and fats.

Types of Soy Protein


In order to separate the protein part of the other components present in the soybean, the plant goes through a process that removes the fat and concentrates the proteins.

The resulting soybean processing product can be divided into three types:

  • Concentrated Soy Protein:After removal of excess fat and moisture, the product obtained contains at least 65% pure protein and a good part of the soybean carbohydrates;
  • Isolated Soy Protein:Similar to isolated whey protein (which is the most concentrated animal protein), isolated soy protein is the purest, most concentrated form of soybeans on sale. Unlike concentrated soybeans, the isolated protein contains few carbohydrates and a high protein content (at least 90%). As the carbohydrates are removed from the mixture, the isolated soy protein has the advantage (in relation to the other types) of not having the accentuated flavor of the legume;
  • Textured Soy Protein:Known popularly as soybeans, or PTS, textured soy protein is a food obtained through industrial processes termed thermoplastic extrusion or spinning. According to the procedure chosen during its manufacture, the PTS may have a protein content of 50% (extrusion) or 90% (spinning).

What does it serve

Protein isolated from soy serves as a protein alternative for non-food users. animal origin, or as a way to increase amino acids in the diet without having to spend so much.

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PIS is still an option for those who are lactose intolerant or else have an eye on cholesterol levels because vegetable protein is naturally free of both nutrients.

For those who practice bodybuilding, isolated soy protein can be a great aid in gaining muscle mass, as it has a good aminogram (that is, it contains all the essential amino acids), which guarantees a good use of amino acids by muscles.


Protein isolated from soy provides a number of important nutrients for health, including potassium, zinc, iron and phosphorus minerals, and B vitamins.

Check the other PIS nutrients present in a spoon of the food (20g portion):

  • Calories: 70 kcal
  • Proteins: 18 g
  • Carbohydrate: 0 g
  • Total Fat: 0g
  • Cholesterol: 0 mg
  • Food fiber: g
  • Calcium: 40mg
  • Sodium: 200mg
  • Isoflavones: 60mg

Soy Protein Isolate x Whey Protein


When compared to whey concentrate, isolated soy protein has the benefit of not containing lactose in its formulation. In addition, soy is naturally cholesterol-free, which makes vegetable protein a good choice for anyone who has problems with LDL (bad cholesterol) levels.

With the exception of these two aspects, we can say that isolated soy protein and whey protein complement each other in a feeding directed towards the gain of muscular mass. While whey protein has a slightly higher concentration of branched-chain amino acids (BCAAs) higher than that of soybeans, vegetable protein provides higher amounts of the amino acids arginine and glutamine.

Arginine stimulates the production of nitric oxide (a gas that causes dilation of the blood vessel wall) and a series of anabolic hormones that promote muscle mass.

Glutamine is essential for energy metabolism and acts on the immune system, as well as regulating the processes of anabolism and catabolism.



It is no wonder that soybeans have been consumed by Asian peoples for more than , 00 years: the legume is linked to a number of benefits, including a food with medicinal properties.

Part of these benefits are extended to isolated soy protein that, while not containing all components of the grains, still retains the major nutrients needed for health.

Learn then what are the main benefits of isolated soy protein:

- Source of High Biological Value Protein

There are basically two types of amino acids: the essential and the non-essential. While the former can not be synthesized by the human organism itself, the essential amino acids are produced naturally by the body from the proteins obtained through food.

Although both are indispensable for the maintenance of metabolism, the essential amino acids deserve attention, since they are not produced internally they must be obtained through diet or supplementation.

Currently, nine amino acids are considered essential, and the greater the concentration of them in a particular protein, the greater the biological value. That is: a protein that presents all nine amino acids will have a better use in the body and will thus be considered complete.

At the top of the list of proteins with the highest biological value are foods of animal origin, such as eggs, meat and dairy products. Soy is the best source of these proteins in the plant kingdom, as it also provides the nine essential amino acids.

Scientists use the PDCAAS method to analyze the quality of a particular protein, and a PDCAAS of 1 is considered the maximum value on the protein scale.

According to this classification, the soy protein is of high biological value since, like the egg and the milk, it has a PDCAAS of 1. In comparative tests developed by the World Health Organization, isolated soy protein showed quality values ​​very similar to those of red meat, egg and milk proteins (casein).

- Auxiliary Muscle Gain

As we have seen above, isolated soybean protein may aid muscle gain, contrary to what many believe, has a high biological value and has a good use of the fibers muscles.

In a study presented at a meeting of theAmerican College of Sports Medicine(which was curiously sponsored by the North American dairy council), researchers have shown that a shake with post-workout soy protein was as effective as a skim milk formulation in gaining mass and increasing strength muscular.

For those responsible for the study, this means that, in fact, the protein obtained from the soy is as efficient as milk proteins for the formation and growth of muscle tissue.

Another research published in 2004 in theNutrition Journalconcluded that both soy protein and whey protein are able to induce muscle mass gain and counteract the negative effects of catabolism.

- Prevents Catabolism

Protein isolated from soybeans has relatively rapid absorption, which is only slightly slower than the absorption of whey protein. Despite this, PIS has much faster absorption than casein and albumin, which makes it a good choice for nourishing muscles efficiently and decreasing muscle catabolism.

- Has antioxidant potential

In addition to poor nutrition, stress and excess pollutants, the practice of high-intensity exercise also contributes significantly to the formation of free radicals.

Although they are a natural byproduct of cellular metabolism, these unstable molecules must be combated to the maximum, because when in excess they cause irreversible damages to the cells. As a result, there can be from the early aging to even the emergence of a number of diseases, such as some cancers.

Soy isoflavones act as a natural antioxidant, helping to combat the excessive formation of free radicals during exercise, an effect that can accelerate post-workout recovery.

- Stimulates fat burning

Here again we have the performance of isoflavones. A study of theApplied Research Instituteof Japan has shown that the soy protein isolated had positive effects in reducing the body fat content of rats.

Although these results have not been conclusively investigated in humans, they are according to one of the effects of isoflavones, which is exactly that of controlling the metabolism of lipids.

Another research published in 2004 in the specialized journalMetabolismfound that the use of isoflavones in combination with physical activity was able to reduce the accumulation of body fat, while at the same time increasing muscle mass and reestablishing mass levels bone.

- Decreases Cholesterol Levels

The same study cited above inMetabolismalso concluded that isoflavone is able to lower the concentration of LDL in the circulation, reducing the risk of clogging of the arteries and consequently of cardiac complications.

A meta-analysis of 38 clinical studies concluded that regular consumption of soy protein isolate may help lower total cholesterol and LDL levels in the bloodstream.

The US Food and Drug Administration (FDA) has determined that consuming 25 grams of soy protein daily can help reduce LDL values ​​by up to 10 percent.

- Weight Loss Assistant

One of the biggest difficulties that those who are dieting encounter is the control of appetite. The decrease in calorie intake sends the brain a signal to increase the urge to eat more unhealthy and caloric foods, which makes it difficult to maintain a food plan restrictive.

In this search for peace with the balance, proteins can be of great help, as they bring satiety and stimulate metabolism. This is because proteins require a greater effort of the digestive system, which is forced to resort own energy stocks to obtain fuel for the breakdown of these proteins into amino acids.

Protein isolated from soybeans may be one of these proteins, as well as acting in the control of appetite still has the advantage of not having carbohydrates and fats. For those who are dieting to eat, consume one or two tablespoons of protein isolated from can be a good way to reduce hunger and avoid the catabolism of muscular.

- Relieves the symptoms of menopause

Several studies suggest that women of Asian origin have fewer menopause symptoms than Western women. One of the explanations would be the fact that soybeans are one of the main diet foods of the Asian people, who consume the legume almost daily.

And, as we have seen, soy contains isoflavones, phytochemicals that act as the estrogen in the body, a naturally diminished hormone in menopause.

A survey conducted byNew England Research Institutesin the United States found that American women of Asian descent had fewer complaints of heat waves and pains in the body than their countrymen.

- Prevents osteoporosis and cancer

Asian women also have considerably lower rates of osteoporosis, which is an interesting fact when we consider that in Asia the consumption of milk was until recently considered quite rare.

This information led scientists to conclude that once again it is the isoflavones that are responsible for such effect, since these phytoestrogens may help to reduce the bone loss naturally associated with menopause.

Other studies also suggest that soy protein contributes directly to a decrease in the rich colon, breast and prostate cancers.



Despite all the benefits, isolated soy protein is also surrounded by doubts, especially regarding the presence of phytoestrogens.

In addition to having a high quality protein content, soy is also distinguished by the presence of isoflavones, which as we have already seen are phytohormones with antioxidant function and that are mainly responsible for the diverse benefits of Soy.

These same isoflavones, however, are a source of great controversy, since there are studies linking excessive consumption of phytohormone to a decrease in endogenous testosterone production.

On the other hand, numerous researches have not been able to find a direct link to soybeans and the emergence of negative effects, be they a hormone production or even the emergence of female characteristics (after all, some say soy would be capable of causing breast men).

What there are, until now, are studies that contradict and do not allow to state that soy is bad or that consuming soy protein can cause an increase in the production of estrogen.

In addition, the protein isolated from soybean has a very low amount of isoflavones, which would not be enough to cause hormonal imbalances in the body.

As the issue is controversial, health professionals recommend the consumption of soybeans in moderate portions, and in a way interspersed with other sources of protein.

How to take

The best way to take soy protein isolate will depend on your goals.

For those who use PIS to gain muscle mass, the tip is to take two spoons diluted in water or fruit juice. Of course you can also dilute it in milk, but in this case it will slow down digestion and absorption of amino acids (which may not be so interesting post-training).

For those who need to lose weight, it is best to dilute the PIS in water or a little skim milk, so as not to exaggerate the amount of calories.

If you do not fit into any of the two groups above, try adding two scoops of soy protein isolate to your menu throughout the day. You can add it to the granola, to the green juice or even to sprinkle a little on the salad.


- Combine soybeans with whey

Studies suggest that soy protein improves athletic performance and even aids post-workout recovery, reducing inflammation and muscle pain. This makes PIS a great alternative to complement your protein shake.

While whey has faster digestion, the proteins isolated from soy are absorbed more gradually. Together, these two proteins can offer a continuous release of amino acids needed for muscle recovery.

- Best time

If you only supplement with PIS, opt for post-workout, which is the time your body is most in need of nutrients to begin the long task of recovering damaged muscle fibers during the bodybuilding.

If you also use whey, it may be a better option for post-workout, because it has faster absorption and is more effective than the isolated soy protein in combating catabolism.

You can take a soy protein shake at any other time of day, wake up and before bed, which are two other critical times for those who are looking for hypertrophy muscular.

- Add a carbohydrate source to your shake

Like whey isolated, PIS contains almost no carbohydrates, but these are essential for better absorption of amino acids by the cells.

The tip is therefore to take PIS with a source of carbohydrates, which can be either a fruit (such as banana) or the popular sweet potato.

- Use creativity

You do not need to consume soy protein alone in the form of a shake. Since it has no sharp taste, you can use it in several other ways, such as replacing wheat flour, fruit, egg omelet or even mixed with rice and beans.

- Be aware of the type of product

As we saw earlier on, soy protein can be found in a less pure form with a lower concentration of amino acids.

To ensure all the benefits of soy protein isolate and do not take along other ingredients (such as carbohydrates and ensure that the product you are purchasing has a minimum of 90% protein formulation.


The price of the isolated soy protein may vary according to the brand and the amount purchased, but overall it can be found for approximately $ 0.00 kilo.

Where to buy

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It is possible to buy soy protein isolated from physical stores of food supplements, or online supplement stores.

Additional references:

  • Anderson, JW, Johnstone BM, Cook-Newell ME. Meta-analysis of effects of soy protein intake on serum lipids in humans. N Engl J Med 1995; 33: 76-282;
  • Atkinson C, Compston JE, Day NE, Dowsett M, Bingham SA. The effects of phytoestrogen isoflavones on bone density in women: a double-blind, randomized, placebo-controlled trial. Am J Clin Nutr. 2004; 9 (2): 326-33;
  • Brown C. Eric et al. Soy versus whey protein bars: Effects on exercise training on lean body mass and antioxidant status. Nutrition Journal. 2004;
  • Jason E. Tang et al. Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in Young men. J app Physiol. 2009;
  • Rossi A., Disilvestro R.A., Blostein-Fugii A. Effects of soy consumption on exercise-induced acute muscle damage and oxidative stress in young adult males. FASEB J 199: 2 (5); A653;
  • Wu J, Wang X, Chiba H, Higuchi M, Nakatani T, Ezaki O, Cui H, Yamada K, Ishimi Y. Combined intervention of soy isoflavone and moderate exercise prevents body fat elevation and bone loss in ovariectomized mice. Metabolism. 2004 Ju; 3 (7): 942-8.

Would you use soy isolated protein as a supplement to gain muscle mass? What are your favorite protein sources? You are vegetarian? Comment below!

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