Amino acids effect: The most important questions and answers

Aminosäuren Wirkung: Die wichtigsten Fragen und Antworten

As you've probably heard, amino acids are essential to our body because they form the cornerstone of all proteins. There are essential amino acids that we can only get from food and non-essential amino acids that our body can produce itself.

The effect of amino acids is said to be performance-enhancing and can also help with weight loss. They can also help against inner restlessness, for example. However, taking it can also be associated with risks, such as extreme nausea. With this article we are trying to provide you with clarity and provide sufficient information about the effects of amino acids.

the essentials in brief

  • Amino acids can be divided into a few types. There are essential amino acids that can only be obtained through food, non-essential ones that the body can also produce itself, and semi-essential amino acids. There are also left-hand and right-hand amino acids.
  • Amino acids are essential to life. They form the cornerstone of every cell in all life on earth. It follows that without amino acids there would be no life. A certain amount of amino acids should therefore always be consumed.
  • An overdose of certain amino acids can sometimes have devastating consequences. That is why it is important to always clarify how much you should be taking before taking it. You can find this information from your doctor or in the package leaflet.

Effects of amino acids: what you should know

The effect of amino acids is highly regarded, especially among athletes. They are said to help build muscle, increase performance and promote weight loss. Whether that's true or just a myth, we'll find out below. Very few people know how amino acids work, which processes take place, or why we need them.

In order to counteract this, important questions about the effects of amino acids will be answered in detail in the following part and supported by scientific studies.

How do amino acids work in the body?

Since there are many amino acids, all of which have different modes of action, there is no general answer to this question. However, when amino acids are taken, they are mostly utilized in the liver.

These are made into proteins or brought into the metabolism. In this they fulfill a wide variety of tasks, such as as messengers in the nervous system. (1)


Amino acids are mostly found in foods that are high in protein, such as eggs or nuts. (Image source: Enrico Mantegazza / unsplash)

To answer the question more clearly, we have listed some important essential amino acids with their effect and the associated food source in the following table.

amino acid Effect food source
leucine May work to build and maintain muscle protein. It can also support healing processes. (2) Walnut, Pea, Chicken, Salmon, Egg
isoleucine May help maintain and regenerate muscle tissue. It also serves as an energy supplier in some sports. (3) Walnut, Pea, Chicken, Salmon, Egg
lysine May help maintain muscle and connective tissue. (4) Chicken, Salmon, Egg, Pumpkin Seeds
methionine Works together with lysine in the synthesis of carnitine. Also directly involved in the formation of proteins. (5) Brazil nut, sesame, salmon, beef, broccoli, corn, spinach
phenylalanine Plays a role in binding proteins and hormones. (6) Soybeans, Peas, Pumpkin Seeds, Poultry, Pork, Egg, Salmon
threonine Participates in isoleucine biosynthesis. (7) Beef, Chicken, Salmon, Peas
tryptophan Is the harbinger of serotonin, and can thus brighten the mood. (8th) Unsweetened Cocoa, Cashew, Peas, Soybeans
valine Serves as an energy supplier for the muscle cells. In addition, it releases some important messenger substances to the nervous system. (9) Peas, Spirulina, Cheese, Chlorella

The amino acids listed are only essential amino acids, i.e. those that can be ingested through food. However, the body is also able to produce some amino acids itself. These include arginine, alanine, glutamine, and more. Showing the effect of each individual would go beyond the scope here.

What do amino acids work against?

Amino acids are said to have a healing or protective effect in many areas. These are usually also proven in many studies. Basically, amino acids are essential for life. However, the question is about an additional intake of amino acids to achieve certain effects.

No proteins without amino acids - no life without proteins!

Amino acids are commonly taken by athletes. They should serve to build muscle and improve performance. This is the so-called BCAA effect. This is caused by the amino acids leucine, isoleucine and valine.

It may be that these amino acids can have a performance-enhancing effect in a certain dose, but this can also be reversed and thus have no positive effect. (10)

img src="" alt="Man jogging">

Amino acids can only have a limited performance-enhancing effect. In the field of fitness, however, they are said to do more than they really can. (Image source: kinkate / pixabay)

In addition, it is often heard that amino acids could improve sleep. This is tryptophan. Since this is the precursor to serotonin and this can have a positive effect on the emotional state, one could see a connection here.

However, this method receives little consideration in medicine. However, there is a possibility that it can work for physical insomnia. (11)

As just mentioned, the amino acid tryptophan as a harbinger of serotonin can improve the emotional state. For this reason, one often hears that it can help against depression. In fact, studies have found evidence of this. The amino acid can significantly improve symptoms of depression or an anxiety disorder. (12)

To conclude this question, we would like to address the widespread assumption that amino acids could protect against wrinkles. It involves several amino acids, such as methionine, which protects the skin from pollutants, or lysine, which can strengthen the skin's surface.

Here, too, it is true that this connection has already been scientifically established. So you may also be able to improve skin texture. (13)

So if you decide to take amino acids for one of the reasons mentioned, the table in the first question will help you. In this you can read how you can take these amino acids in the form of food to bring about the desired effect.

When do amino acids take effect?

The invisible effect of amino acids sets in quite quickly. The situation is different when it comes to the question of when you can see the first successes. This usually depends on the reason for taking it and which amino acids it is.

The fact that the effect of amino acids sets in quickly can be seen from the fact that the amino acid concentration in the blood already increases about 30-90 minutes after ingestion. Logically, however, no visible successes will be noticeable during this time.

When it comes to taking amino acids before a workout, it's said that you should take them about 30-60 minutes before your workout so they can have their post-workout muscle building effects. However, since the effect in sports is questionable, there is no clear answer to this.

Manufacturers of products containing amino acids estimate the time to success for mood issues as 1-3 weeks. In the case of problems with wrinkles or hair, the time required for visible success is estimated at over 3. This makes it clear that what the amino acids are being used against is very important.

So if you decide to supplement with amino acids, don't be disappointed if you still don't see any results after a few weeks. These can be a long time coming. It is important that you do not exceed or fall below the recommended dose.

What effects can an overdose of amino acids cause?

There are some risks associated with an overdose of amino acids. It depends on which amino acid it is.

You should never exceed a certain dose for individual acids. In the table below we have listed the essential amino acids with their daily dose and the possible consequences of an overdose for illustration purposes.

amino acid Daily dosage Possible effect of overdose
leucine 10 - 14 mg/kg body weight Nausea, vomiting, abdominal pain, diarrhea
isoleucine 10 - 15 mg/kg body weight In healthy people, an overdose is usually immediately converted into storage fat. Pre-ill people should see a doctor as the effects can be devastating in many ways.
lysine 20 - 40 mg/kg body weight Kidney dysfunction, blood clotting disorder, blood sugar fluctuations
methionine 0.5 - 1 g 3 times a day Irritability, dizziness, drowsiness, nausea, diarrhea
phenylalanine 25 mg/kg body weight renal dysfunction
threonine 8 - 16 mg/kg body weight Elevated levels of uric acid, which can lead to gout in the long term.
tryptophan 250-1500mg Dizziness, headache, sensitivity to light, tiredness, slowed reflexes
valine 1.5-3g Disturbance of the neurotransmitter balance

When taking amino acids, you should always pay attention to the information provided by the doctor and/or the package leaflet!

In principle, it is not so easy to overdose on an amino acid in such a way that severe effects occur. This usually requires an overdose spread over several days. However, if you notice that you have taken too much than the daily dose when taking it, it is best to contact your doctor.

What side effects can amino acids have?

The additional intake of amino acids can also cause side effects beyond an overdose. These are usually written down in the package insert of the respective preparation. In the following list you will find some side effects that can also be recorded without an overdose.

  • nausea
  • Vomit
  • Diarrhea
  • stomach pain
  • mood swings
  • fatigue

If you experience one or more side effects, it is best to talk to your doctor about taking it, who will help you.

tablets in hand

One should never be careless with amino acids! Incorrect dosing can potentially have far-reaching consequences. (Image Source: Hasty Words / pixabay)

In addition to possible side effects, amino acids also have some interactions with each other or with other drugs.

An example of this is the combination of tryptophan and antidepressants. Taking both substances increases the serotonin balance. This can lead to hyperactivity, high blood pressure or insomnia.

An example of an interaction between amino acids is the combination of lysine and arginine. These two compete in effectiveness. Taking both in isolation can therefore lead to severe side effects. Therefore, both preparations should always be taken together. This can positively lead to an improvement in anxiety disorders. (14)


Based on the studies and sources used, it can be said that amino acids can sometimes work wonders. In the case of problems with depression, wrinkles or sleep disorders, certain amino acids can help to significantly improve the symptoms. However, there are also reasons why there are often doubts about them.

In sports, for example, taking amino acids can actually do the opposite of the desired goal. It can even weaken muscle growth if taken incorrectly.

In addition, interactions and side effects can occur and an overdose can have serious consequences. In summary, amino acids can be helpful for certain goals, but they should always be treated with caution.


  1. National Research Council (US) Subcommittee on the Tenth Edition of the Recommended Dietary Allowances. Washington (DC): National Academies Press (US); 1989
  2. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6106, Leucine. Retrieved January 7, 2021 from
  3. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6306, l-isoleucine. Retrieved January 7, 2021 from
  4. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 16130064, L-Lysine,. Retrieved January 7, 2021 from
  5. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6137, Methionine. Retrieved January 7, 2021 from
  6. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6137, Methionine. Retrieved January 7, 2021 from
  7. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6288, L-Threonine. Retrieved January 7, 2021 from
  8. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 54608559, L-Tryptophan,. Retrieved January 7, 2021 from
  9. National Center for Biotechnology Information (2021). PubChem Compound Summary for CID 6287, Valine. Retrieved January 7, 2021 from
  10. Wolfe RR. Branched-chain amino acids and muscle protein synthesis in humans: myth or reality? J Int Soc Sports Nutr. 2017 Aug 22;14:30. doi: 10.1186/s12970-017-0184-9. PMID: 28852372; PMCID: PMC5568273.
  11. Wang D, Li W, Xiao Y, He W, Wei W, Yang L, Yu J, Song F, Wang Z. Tryptophan for the sleeping disorder and mental symptom of new-type drug dependence: A randomized, double-blind, placebo - controlled trial. Medicine (Baltimore). 2016 Jul;95(28):e4135. doi: 10.1097/MD.0000000000004135. PMID: 27428201; PMCID: PMC4956795.
  12. Lindseth G, Helland B, Caspers J. The effects of dietary tryptophan on affective disorders. Arch Psych Nurs. 2015 Apr;29(2):102-7. doi: 10.1016/j.apnu.2014.11.008. Epub 2014 Dec 9. PMID: 25858202; PMCID: PMC4393508.
  13. Takaoka M, Okumura S, Seki T, Ohtani M. Effect of amino-acid intake on physical conditions and skin state: a randomized, double-blind, placebo-controlled, crossover trial. J Clin Biochem Nutr. 2019 Jul;65(1):52-58. doi: 10.3164/jcbn.18-108. Epub 2019 May 24. PMID: 31379414; PMCID: PMC6667387.
  14. Smriga M, Ando T, Akutsu M, Furukawa Y, Miwa K, Morinaga Y. Oral treatment with L-lysine and L-arginine reduces anxiety and basal cortisol levels in healthy humans. Biomed Res. 2007 Apr;28(2):85-90. doi: 10.2220/biomedres.28.85. PMID: 17510493.
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