Last updated: August 11, 2021

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Have you ever wondered what amino acids are needed for in your body and how you can get them? You are probably also wondering what the symptoms of an isoleucine deficiency can be and what you can do about it.

We answer these and other questions in our big isoleucine test 2021. We explain what products are available on the market and what you have to look out for when buying them. We also give you important background information from current studies on the topic of isoleucine.




The most important facts

  • Together with other amino acids, isoleucine belongs to the essential proteinogenic amino acids. These are not produced by the body, but must be taken in through food or dietary supplements.
  • Meat, dairy products or cereals are a natural source of isoleucine. If this is not enough, isoleucine is available in capsule, powder or liquid form. There is no exact amount, but a guideline is 20 mg of isoleucine per kilogram of body weight.
  • Isoleucine is depleted during sport, but also through physical stress such as operations or illness. An isoleucine deficiency can cause symptoms such as muscle weakness, fatigue or listlessness.

The Best Isoleucine: Our Picks

Buying and evaluation criteria for isoleucine

There are many different products that contain isoleucine. Based on our criteria, we would like to give you some tips so that you can buy the right product for you. You should consider the following points:

In the following sections, we have explained the individual criteria in more detail. These should help you find the right isoleucine product for you.

Quantity per pack

The quantity per pack is crucial. You should always calculate the price of the different products to one unit so that you can really compare the products.

For capsules, it is worth calculating per individual capsule.

For powders, you can calculate the price per portion. For drinks you should compare the price per litre, you can do the same for shots.

Of course, you always have to consider how often you want to take isoleucine. Depending on how often you want to consume isoleucine, it may be worthwhile to buy a smaller package so that you don't buy too much isoleucine or the product expires before you have used it all.

Animal or Vegan

Isoleucine is found in a variety of foods. Among others, in meat, dairy products and cereals. If you are vegetarian or even vegan, look for a vegan version. There is also synthetic isoleucine on the market.

However, you will not notice any difference in quality or effect. The products are always the same isoleucine. If you are not sure whether you want a vegan or animal product, you can simply ask for advice.

Dosage

Depending on the type of product, the amount of isoleucine varies greatly. Often, only the total number of all amino acids contained is stated. First find out how much isoleucine you should take. This is often reflected in the price. Compare the amount of isoleucine per 100g on the package. This will help you choose the right product.

Compare the individual product
descriptions.

BCAA powders often contain the right ratio of essential amino acids. You can use the measuring spoon provided to determine the correct amount. In the case of capsules, it is indicated how many capsules you should take per day.

In any case, it is worth consulting your fitness coach. Otherwise, you may spend a lot of money on the products but not feel any effects due to incorrect use.

Taste

While the isoleucine capsules are tasteless, the powder or drinks come in various flavours. Drinks are available in orange, cherry or green tea-lemon flavours. With the powder, there is a much wider choice. In addition to the neutral variant, we have found flavours such as:

  • Orange
  • Cola
  • Peach
  • Melon
  • Blackcurrant
  • Apple
  • Cassis
  • Lemon

Depending on the manufacturer, the choice is larger or smaller. First decide on the product and only then on a flavour. Otherwise, your product may not come in the desired flavour and you may be disappointed.

Type Flavours
Capsules and tablets Flavourless
Powders and drinks Wide range of common and unusual flavours

Which flavour you choose depends on your personal preference. Opt for a smaller pack at the beginning or ask your shop assistant if there is a possibility to try it.

Other ingredients

When making your choice, also consider what other ingredients are included and how much. In particular, sugar and fat are important metrics if you are using the product during weight loss.

In addition, some products contain substances such as gelatine, which is made from animal connective tissue. They also contain colourings or other binding agents.

Guide: Frequently asked questions about isoleucine answered in detail

Below we have answered the most important questions about isoleucine. We have analysed and summarised various studies for you. You should then have a good basis for deciding whether or not to take isoleucine.

What is isoleucine and what effect does it have?

Together with leucine and valine, isoleucine is one of the essential proteinogenic amino acids, also called BCAA. BCAA stands for branched chain amino acids.(1, 2)

Isoleucin-1

Isoleucine can also be taken in powder form.
(Image source: HowToGym on Unsplash)

However, the body cannot produce it itself, but must absorb it through food or supplements. Isoleucine is an essential nutrient for humans, both for physiological and immune functions. Isoleucine also plays a role in the body's growth and protein metabolism, as well as in glucose transport.(1, 2, 3)

However, you will most often come across BCAAs in connection with sport. They are supposed to help build muscle, shorten the recovery time or prevent muscle loss during a diet. However, if you only focus on the intake of BCAAs or isoleucine in particular, the effects will not be as great. Other proteins and amino acids must also be consumed.(3, 4, 5)

Isoleucin-2

Isoleucine is mainly taken by athletes.
(Image source: John Arano on Unsplash)

But beware: Taking supplements such as BCAA powder with isoleucine, isoleucine drinks or shots do not replace a meal! They are supplements and not substitutes. This also applies to all other products such as protein powders or vitamin supplements.

What does isoleucine contain?

Since isoleucine cannot be produced by the body, it must be taken in through food. Meat and products containing meat are best suited for this.(2, 3)

Isoleucin-3

Meat offers the largest natural source of isoleucine.
(Image source: Victoria Shes on Unsplash)

Likewise, isoleucine is found in grains such as wheat. So products like bread, pasta or corn are good sources. Isoleucine is also found in milk or dairy products.(2, 3)

How much isoleucine is needed per day?

There is no generally valid statement on how much isoleucine should be taken in per day. However, the following formula has become accepted in science: 20 mg of isoleucine per kilogram of body weight should be consumed per day(6). Other studies speak of 10 to 20 grams of BCAA per day.(7, 8, 9)

The best way to determine the exact amount is to talk to your fitness coach or get advice from a pharmacy or your family doctor. Especially if you have a deficiency or are on a diet, it is worthwhile to determine the exact dosage.

At what time should I take isoleucine?

The effect depends decisively on the time at which you take isoleucine. The further away the time is from the sporting activity, the less great the effect. Although various studies have investigated whether taking isoleucine before or after training is better, no clear difference was found. (13, 14)

Again, it is worth consulting your fitness coach or a pharmacy staff member. Often, personal experience can also help you make your decision.

What types of isoleucine are there?

Isoleucine is available both as a pure substance in capsules and in combination with other important amino acids and caffeine. The following list should give you a brief overview.

Product type Properties
Isoleucine capsules or tablets Isoleucine with high purity. This prevents the absorption of other substances and allows the amount to be adjusted
BCAA powder combination of all essential amino acids. Drink can be prepared by the user
BCAA Drink Ready-to-use drink that can be easily transported
BCAA-Shot Small amount, but highly dosed

Which product you choose depends on the area of application.

How much does isoleucine cost?

Depending on which of the types described above you choose, the price will vary. We have compiled a brief price overview for you in the table below.

Type price
Isoleucine capsules approx. 25 to 50 euros, depending on pack size
BCAA powder approx. 10 to 50 euros, depending on pack size
BCAA drink approx. 5 to 8 euros per litre
BCAA shot approx. 1.50 to 3 euros per shot

In any case, get advice from a specialist before buying so that you buy the right product for you. It is best to compare the price per kilogram for powder and the price per litre for drinks. For the shots, it is worth calculating the price per shot.

How does an isoleucine deficiency develop and what are the symptoms?

An isoleucine deficiency occurs during energy production, especially during sports or dieting. However, amino acids are also increasingly depleted by the body during physical or physical stress, for example during operations or illnesses. (11)

Isoleucin-4

When you are ill, your body breaks down amino acids such as isoleucine.
(Image source: Natinal Cancer Institute on Unsplash)

The body reacts to this with muscle weakness, listlessness and fatigue. But mental exhaustion is also a sign of isoleucine deficiency.(9, 10)

What alternatives are there to isoleucine?

As isoleucine is an essential amino acid, there is no alternative. Isoleucine is needed by the body and must be taken in through food or special dietary supplements such as powder or capsules. (1, 2, 3)

How is isoleucine produced?

There are several methods of extracting amino acids from substances. Fermentation with microorganisms decomposes the starting substances. There is also the possibility of decomposing the substances with enzymes. Finally, there is the possibility of producing isoleucine through synthesis. (12)

However, you don't have to worry about the manufacturing process when choosing your product. The end result is always the same and you will have isoleucine in your product.

Photo source: Dudzi?ski/ 123rf.com

References (14)

1. Gu C, Mao X, Chen D, Yu B, Yang Q. Isoleucine Plays an Important Role for Maintaining Immune Function. Curr Protein Pept Sci. 2019;20(7):644-651. doi: 10.2174/1389203720666190305163135. PMID: 30843485.
Source

2. Schütz L-M. (2020). Nahrungsergänzungsmittel im sportlichen Bereich: Verzweigtkettige Aminosäuren und ihr Einfluss auf die sportliche Leistungsfähigkeit. Hamburg: Diplomica Verlag. ISBN: 978-3-86341-622-5
Source

3. Górska-Warsewicz H, Laskowski W, Kulykovets O, Kudlińska-Chylak A, Czeczotko M, Rejman K. Food Products as Sources of Protein and Amino Acids-The Case of Poland. Nutrients. 2018 Dec 13;10(12):1977. doi: 10.3390/nu10121977. PMID: 30551657; PMCID: PMC6315330.
Source

4. Blomstrand E, Eliasson J, Karlsson HK, Köhnke R. Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J Nutr. 2006 Jan;136(1 Suppl):269S-73S. doi: 10.1093/jn/136.1.269S. PMID: 16365096.
Source

5. Coombes JS, McNaughton LR. Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after prolonged exercise. J Sports Med Phys Fitness. 2000 Sep;40(3):240-6. PMID: 11125767.
Source

6. Brestenský, M., Nitrayová, S., Patráš, P., Heger, J., & Nitray, J. (2015). Branched chain amino acids and their importance in nutrition. Journal of Microbiology, Biotechnology and Food Sciences, 05(02), 197–202. https://doi.org/10.15414/jmbfs.2015.5.2.197-202
Source

7. Blomstrand E, Hassmén P, Ek S, Ekblom B, Newsholme EA. Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise. Acta Physiol Scand. 1997 Jan;159(1):41-9. doi: 10.1046/j.1365-201X.1997.547327000.x. PMID: 9124069.
Source

8. Blomstrand E, Hassmén P, Ekblom B, Newsholme EA. Administration of branched-chain amino acids during sustained exercise--effects on performance and on plasma concentration of some amino acids. Eur J Appl Physiol Occup Physiol. 1991;63(2):83-8. doi: 10.1007/BF00235174. PMID: 1748109.
Source

9. Hassmén P, Blomstrand E, Ekblom B, Newsholme EA. Branched-chain amino acid supplementation during 30-km competitive run: mood and cognitive performance. Nutrition. 1994 Sep-Oct;10(5):405-10. PMID: 7819652.
Source

10. Arndt K, Albers, T. (2011) Handbuch Protein Und Aminosäuren: Optimaler Einsatz Von Protein & Aminos Im Sport, in Der Diät, Bei Erkrankungen, Zur Gesundheitsvorsorge : Beste Kombinationen Und Exakte Angaben Zu Dosierungen, Neben- Und Wechselwirkungen. 3. Aufl. Arnsberg: Novagenics ISBN: 978-3-929002-38-6
Source

11. Schmidt E, Schmidt N. (2004). Leitfaden Mikronährstoffe. München: Urban & Fischer Verlag ISBN: 978-3437565403
Source

12. Chibata I, Itoh T, Izumi Y. (1978). Production and Utilization of Amino Acids. Angewandte Chemie, Ausgabe(17), 176 - 183. https://doi.org/10.1002/anie.197801761
Source

13. Ra SG, Miyazaki T, Kojima R, Komine S, Ishikura K, Kawanaka K, Honda A, Matsuzaki Y, Ohmori H. Effect of BCAA supplement timing on exercise-induced muscle soreness and damage: a pilot placebo-controlled double-blind study. J Sports Med Phys Fitness. 2018 Nov;58(11):1582-1591. doi: 10.23736/S0022-4707.17.07638-1. Epub 2017 Sep 22. PMID: 28944645.
Source

14. Howatson G, Hoad M, Goodall S, Tallent J, Bell PG, French DN. Exercise-induced muscle damage is reduced in resistance-trained males by branched chain amino acids: a randomized, double-blind, placebo controlled study. J Int Soc Sports Nutr. 2012 Jul 12;9:20. doi: 10.1186/1550-2783-9-20. PMID: 22569039; PMCID: PMC3395580.
Source

Why you can trust me?

Wissenschaftliche Studie
Gu C, Mao X, Chen D, Yu B, Yang Q. Isoleucine Plays an Important Role for Maintaining Immune Function. Curr Protein Pept Sci. 2019;20(7):644-651. doi: 10.2174/1389203720666190305163135. PMID: 30843485.
Go to source
Bachelorarbeit
Schütz L-M. (2020). Nahrungsergänzungsmittel im sportlichen Bereich: Verzweigtkettige Aminosäuren und ihr Einfluss auf die sportliche Leistungsfähigkeit. Hamburg: Diplomica Verlag. ISBN: 978-3-86341-622-5
Go to source
Wissenschaftliche Studie
Górska-Warsewicz H, Laskowski W, Kulykovets O, Kudlińska-Chylak A, Czeczotko M, Rejman K. Food Products as Sources of Protein and Amino Acids-The Case of Poland. Nutrients. 2018 Dec 13;10(12):1977. doi: 10.3390/nu10121977. PMID: 30551657; PMCID: PMC6315330.
Go to source
Wissenschaftliche Studie
Blomstrand E, Eliasson J, Karlsson HK, Köhnke R. Branched-chain amino acids activate key enzymes in protein synthesis after physical exercise. J Nutr. 2006 Jan;136(1 Suppl):269S-73S. doi: 10.1093/jn/136.1.269S. PMID: 16365096.
Go to source
Wissenschaftliche Studie
Coombes JS, McNaughton LR. Effects of branched-chain amino acid supplementation on serum creatine kinase and lactate dehydrogenase after prolonged exercise. J Sports Med Phys Fitness. 2000 Sep;40(3):240-6. PMID: 11125767.
Go to source
Wissenschaftliche Studie
Brestenský, M., Nitrayová, S., Patráš, P., Heger, J., & Nitray, J. (2015). Branched chain amino acids and their importance in nutrition. Journal of Microbiology, Biotechnology and Food Sciences, 05(02), 197–202. https://doi.org/10.15414/jmbfs.2015.5.2.197-202
Go to source
Wissenschaftliche Studie
Blomstrand E, Hassmén P, Ek S, Ekblom B, Newsholme EA. Influence of ingesting a solution of branched-chain amino acids on perceived exertion during exercise. Acta Physiol Scand. 1997 Jan;159(1):41-9. doi: 10.1046/j.1365-201X.1997.547327000.x. PMID: 9124069.
Go to source
Wissenschaftliche Studie
Blomstrand E, Hassmén P, Ekblom B, Newsholme EA. Administration of branched-chain amino acids during sustained exercise--effects on performance and on plasma concentration of some amino acids. Eur J Appl Physiol Occup Physiol. 1991;63(2):83-8. doi: 10.1007/BF00235174. PMID: 1748109.
Go to source
Wissenschaftliche Studie
Hassmén P, Blomstrand E, Ekblom B, Newsholme EA. Branched-chain amino acid supplementation during 30-km competitive run: mood and cognitive performance. Nutrition. 1994 Sep-Oct;10(5):405-10. PMID: 7819652.
Go to source
Fachbuch
Arndt K, Albers, T. (2011) Handbuch Protein Und Aminosäuren: Optimaler Einsatz Von Protein & Aminos Im Sport, in Der Diät, Bei Erkrankungen, Zur Gesundheitsvorsorge : Beste Kombinationen Und Exakte Angaben Zu Dosierungen, Neben- Und Wechselwirkungen. 3. Aufl. Arnsberg: Novagenics ISBN: 978-3-929002-38-6
Go to source
Fachbuch
Schmidt E, Schmidt N. (2004). Leitfaden Mikronährstoffe. München: Urban & Fischer Verlag ISBN: 978-3437565403
Go to source
Wissenschaftliche Studie
Chibata I, Itoh T, Izumi Y. (1978). Production and Utilization of Amino Acids. Angewandte Chemie, Ausgabe(17), 176 - 183. https://doi.org/10.1002/anie.197801761
Go to source
Wissenschaftliche Studie
Ra SG, Miyazaki T, Kojima R, Komine S, Ishikura K, Kawanaka K, Honda A, Matsuzaki Y, Ohmori H. Effect of BCAA supplement timing on exercise-induced muscle soreness and damage: a pilot placebo-controlled double-blind study. J Sports Med Phys Fitness. 2018 Nov;58(11):1582-1591. doi: 10.23736/S0022-4707.17.07638-1. Epub 2017 Sep 22. PMID: 28944645.
Go to source
Wissenschaftliche Studie
Howatson G, Hoad M, Goodall S, Tallent J, Bell PG, French DN. Exercise-induced muscle damage is reduced in resistance-trained males by branched chain amino acids: a randomized, double-blind, placebo controlled study. J Int Soc Sports Nutr. 2012 Jul 12;9:20. doi: 10.1186/1550-2783-9-20. PMID: 22569039; PMCID: PMC3395580.
Go to source
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