The following essential amino acids are the three Branched Chain Amino Acids or BCAAs: L-Valine, L-Leucine and L-Isoleucine.

You will learn

  • The benefits of BCAAs to the human body
  • How many BCAAs you need every day
  • Which foods contain BCAAs

BCAAs are a popular and widely available fitness supplement. They are particularly well known in body-building and other sports requiring growth of strong muscle tissue. They cannot be synthesised by the body and therefore have to be supplemented via foods containing protein and are therefore classed as essential amino acids.


BCAAs play a pivotal role in human metabolism and are actively used in the treatment against cirrhosis of the liver and in intensive care with great success.


amino acid L-ValineThe branched-chain amino acid L-Valine has industrial applications in the fermentation of alcoholic beverages and is a central building block of many important enzymes. It assists in the human body’s energy provisioning processes and therefore plays an important role in building physical strength and muscle mass. Foods containing large amounts of L-Valine are very popular with athletes and especially body builders, who attempt to accelerate muscle hypertrophy (growth) in order to gain strength, power and speed.


L-Leucine plays a central role in the metabolism of muscle tissue therefore contributing to both its generation and preservation. It is an important building block for many proteins and therefore supports various healing processes. Adults should consume 10 to 50 mg L-Leucine per kilo body weight. A deficiency, however, can also be caused by an undersupply of Vitamin B6.


L-Alanine is a proteinogenic amino acidIn a similar fashion, the BCAA L-Isoleucine plays a pivotal role in the energy supply of muscle tissue, which is particularly critical during periods of extensive exercise or in acute hunger periods.

Unless present in sufficient quantity in the blood, the body will access its storage reserves, which will inevitably lead to a reduction of L-Leucine and muscle mass. This effect must be avoided by athletes trying to build muscle mass.

Foods with large amounts of BCAAs

Branched chain amino acids are contained mainly in protein rich foods and make up three out of the eight essential amino acids. With a balanced and healthy diet it should be no problem to cover the body’s daily minimum requirements. Certain factors, however, can radically increase this minimum requirement to the extend that supplementation becomes necessary.

diets generally deplete the body of BCAAsThe Flash Diet for example drastically reduces the body’s BCAA depots and the body will require urgent replenishment to avoid the breaking down of muscle tissue to source BCAAs for maintenance or muscle repair elsewhere.

Liver conditions and high intensity exercise will also increase the requirement of Leucine, Valine und Isoleucine. Athletes and patients should therefore consumer extra amounts regularly.

Foods particularly rich in L-Leucine are beef (approx. 1690 mg / 100 g), raw salmon (approx. 1615 mg / 100 g), eggs (approx. 1090 mg / 100 g) and wheat products (approx. 920 mg / 100 g).

L-Valine und L-Isoleucine are also included in significant amounts in meat and other animal produce. Dried peas (approx. 1160 mg / 100 g) and walnuts (approx. 750 mg / 100 g) are particularly suited for vegetarians with their high BCAA concentration.

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Meat eaters will get large amounts of their minimum daily requirement from chicken breast (approx. 1220 mg / 100 g) and rice  (approx. 330 mg / 100 g). A healthy adults needs about 10g per day, but this amount will vary between individuals of course.

If you exercise regularly it is worth considering taking either a dedicated BCAA supplement or consuming them with whey protein powder.

The aminoacidstudies team has compared the top 7 whey protein powders to help you find which one is right for you.

Functions of BCAAs

Energy supply of muscle tissue

BCAAs help build muscleUnlike most amino acids, BCAAs are predominantly metabolised in the muscles and not in the liver. This demonstrates their extraordinary importance in the energy supply of muscle tissue.

They are also useful in treating protein tissue reducing conditions such as tumors, because they reduce the natural amino acid catabolism or break down. In chronic liver conditions a sufficient supply of BCAAs is critical, because it can stop the transfer of potential harmful substances from the blood to the brain.

L-Leucine in particular plays a vital role in the generation and preservation of muscle tissue by supporting protein synthesis in the muscle and liver and blocking the breakdown of muscle tissue. It also regulates the energy supply of the body and plays a part in the synthesis of glucose. It is therefore advised to supplement it during low carbohydrate diets.

L-Valine is important in the biosynthesis of protein and the proper conversion of food into energy. This means it is an important muscle nutrient and is regularly supplemented by professional athletes.

Stimulation of insuline production

Another important property of this nutrient is the stimulation of insuline production which controls the blood sugar and accelerates the absorption of amino acids in muscle and liver. Supplying the body with too little L-Valine can result in disruptive growth and reduction of muscle tissue.

excess fat is often caused by irregular insulin levels

The third BCAA L-Isoleucine is also a crucial building block for protein synthesis and can significantly aid the energy supply of the mitochondria, the power plants inside each cell. Other important functions of BCAAs are the stimulation of insuline production and consistent maintenance of nitrogen levels inside the body.

This is particularly important for the generation of new tissue and makes possible healthy growth especially in children and adolescents. In the very rare case of an overdose, this amino acid is easily excreted by the body via urine and therefore does not cause any side effects in the body.

BCAAs can be used to effectively treat certain illnesses, because they play such an important role in many crucial metabolic processes. L-Leucine and L-Valine are particularly important, wich has been shown by many scientific studies in the past.



The effect of L-Leucine supplementation on protein synthesis in senile patients was investigated recently. The group was given four grams of L-Leucine per day with their meals. It was then confirmed that an improved protein synthesis and parallel phosphorylation of particular dietary neurotransmitters important in nutrition was a direct result of the regular consumption of Leucine via the dietary supplements. 1.

Building muscle tissue is therefore highly relevant not just for bodybuilders, but also for more mature people, who intend to lead an active anti-ageing lifestyle and eat and supplement according to their metabolic needs.

Lose weight with BCAAs
Lose weight with BCAAs

In 2010 an additional study showed the interdependency between a daily supply of BCAAs and a subject’s individual body weight based on BMI (Body-Mass-Index). Specifically it was shown that a high BCAA concentration  BCAA correlates with a low occurrence of adipositas (fatty heart) and an appropriate supplementation will have an extremely positive effect on the subject’s general health2.

BCAAs and amino acids in general play important role in healthy, sustainable weight loss.

Furthermore, it has been shown that an insufficient supply of BCAAs can contribute to causing diabetes 3. The same researchers showed that an additional supplementation of  L-Leucine, L-Valine and L-Isoleucine can stimulate the production of insuline in existing cases of diabetes and therefore contributes to improving the general condition of patients.

Similar results have been found in studies looking at links between L-Arginine und L-Carnitine and diabetes.


Branched Chain Amino Acids (BCAA) are essential to the human body and critical for muscle hypertrophy (growth) and maintenance. They have a significant positive effect on the generation of various tissues, healing and metabolic processes via the protein synthesis in the liver.

Walnuts and mais flower as plant-based sources and meat, milk and eggs are most appropriate to cover the recommended daily allowance. If the body does not receive a minimum amount of L-Valine, L-Leucine und L-Isoleucine, which can easily happen in professional athletes the shortage can easily compensated by consuming dietary supplements, which are also beneficial in the prevention and treatment of certain illnesses such as diabetes.

Supplementation is recommended especially during periods of highly intensive exercise which will promote the growth of muscle tissue.

BCAAs should also be supplemented to complement food during weight-loss diets to counteract muscle atrophy as the body may significantly lack certain nutrients. Most of the formula diets are designed to supply the critical nutrients to the body such as amino acids including L-Valine, L-Leucine and L-Isoleucine and are therefore highly recommended for healthy and sustainable weight loss.


Referenced BCAA studies:

  1. Casperson SL et al.: L-Leucine supplementation chronically improves muscle protein synthesis in older adults consuming the RDA for Protein; Clin Nutr. 2012 Feb 20
  2. Qin LQ et al.: Higher branched-chain amino acid intake is associated with a lower prevalence of being overweigth or obese in middle-aded east asian and western adults; J Nutr. 2010 Dec 15
  3. Takeshita Y et al.: Beneficial effect of branched-chain amino acid supplementation on diabetes in patients with insulin resistance: Implications for type 2 diabetes. Metabolism. 2012 Apr 19


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