L-Tryptophan – The amino acid for mood and sleep

The amino acid L-tryptophan is involved in numerous important processes in our body and influences, among other things, our mood and sleep behavior. Here we explain which foods have a good tryptophan content, how exercise affects tryptophan metabolism and how our sleep is improved by this amino acid.

Table of Contents

  1. The amino acid L-tryptophan
  2. The influence of L-tryptophan on mood and sleep
  3. Sport & L-Tryptophan
  4. The best L-tryptophan sources
  5. Use and application of L-tryptophan
  6. Conclusion

1. The amino acid L-tryptophan

L-Tryptophan belongs to the group of essential amino acids. This means that this amino acid cannot be produced by our body itself and should therefore be consumed in sufficient form through food. A deficiency of L-tryptophan affects numerous mechanisms in the body. This is because L-tryptophan is simultaneously a hormone and neurotransmitter precursor and is therefore significantly involved in many important body functions, for example in the construction of various proteins in our muscles, and serves as a precursor to vitamin B3. The effects of L-tryptophan are often described as mood-enhancing, calming and even weight-reducing.

Sportliche Frau ernährt sich morgens gesund

2. The influence of L-tryptophan on mood and sleep

L-tryptophan absorbed via the foodg can be transported via the bloodstream to our cells in the muscles and brain, where it is further processed. The enzyme tryptophan hydroxylase creates 5-hydroxytryptophan (5-HTP) and then our happiness hormone serotonin. However, this process can easily be influenced and disrupted, for example, by a vitamin B6/vitamin B3 deficiency, insulin resistance, magnesium deficiency or stress. Therefore, sufficient intake or the avoidance of disruptive factors must be taken into account. Due to the direct connection to serotonin metabolism, L-tryptophan is also said to have a mood-enhancing effect.

The L-tryptophan metabolism

Tryptophan Stoffwechsel


Towards the evening and as darkness increases, serotonin in the brain is converted into the sleep hormone melatonin, which regulates sleep significantly and ensures that we get tired in the evening and fall asleep. As a basic building block in the biosynthesis of serotonin and its later conversion into melatonin, an adequate supply of the amino acid L-tryptophan is of great importance for a healthy sleep-wake rhythm.

This positive effect on sleep has also been proven in scientific studies, in which additional intake of the amino acid shortened the time it took the test subjects to fall asleep and improved sleep quality.

Gut schlafende Frau dank Tryptophan

3. Sport & L-Tryptophan

Many people are not aware of the close connection between sports activity and L-tryptophan. Physical activity improves the uptake of L-tryptophan into the brain, laying the foundation for increased central serotonin production. Various studies also indicate that L-tryptophan appears to have a positive effect on performance and the ability to regenerate. Regular physical activity also has a very positive effect on sleep behavior by activating numerous metabolic processes, including:a also through the L-tryptophan – serotonin – melatonin connection described above. In addition, the amino acid also plays a role in the regulation of our immune system. During an immune reaction, enzymes are activated to limit the availability of L-tryptophan to virus-infected cells or cancer cells and thus limit their growth. For this reason, reduced tryptophan levels are observed in the blood of these patients, and this is sometimes accompanied by a depressive mood.

4. The best sources of L-tryptophan

Since L-tryptophan is constantly processed in our body, it must be consumed daily. The amount required depends primarily on body weight, so that for healthy adults approx. 5 mg of L-tryptophan per kilogram of body weight per day is recommended. A need that can be easily met given the high natural occurrence in plant and animal foods.

Tryptophan Quellen in Nahrungsmitteln zum Essen Trinken und besser schlafen

The following foods are good sources of L-tryptophan:

  • Soybeans: 590mg
  • Emmental cheese: 460mg
  • Cashew nuts: 450mg
  • Sunflower seeds: 310mg
  • Veal fillet: 310mg
  • Chicken breast: 310mg
  • Tuna: 300mg
  • Chicken egg: 230mg
  • Oatmeal: 190mg
  • Walnuts: 170mg

All information per 100g of food

Fortunately, L-tryptophan has a high resistance to heat and is hardly lost when preparing food.

5. Use & Application of L-Tryptophan

A deficiency in the amino acid L-tryptophan can lead to the following symptoms:

  • Mood swings up to depressive moods and depression
  • Inner restlessness and anxiety
  • Sleep disorders
  • Loss in performance & lack of drive

An L-tryptophan deficiency can normally be compensated for by a healthy diet. Especially people with poor eating habits or certain metabolic diseases (e.g.b sugar malabsorption) but can benefit from dietary supplementation with L-tryptophan. Most L-tryptophan supplements contain between 0.5 and 5g of tryptophan. It can ideally be taken with a sugary drink because L-tryptophan is increasingly absorbed across the blood-brain barrier under the influence of insulin and can therefore promote serotonin and melatonin production. Since L-tryptophan has no known negative effects on the organism, even in high doses, overdoses are currently not known.

6. Conclusion

    • L-Tryptophan is an important amino acid and is a central building block in the formation of the happiness hormone serotonin and the sleep hormone melatonin, which means it can influence our mood and sleep behavior.
    • Sports activity and sugary foods promote the absorption of L-tryptophan into the brain.
      • The daily L-tryptophan requirement can usually be met through diet. In exceptional situations, supplements can also be helpful.

      Greetings and see you soon!

       smartsleep Schlaf Experte Dr. Markus Dworak

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