Does tryptophan increase serotonin? (5+ benefits)

In this article, we will explore whether tryptophan increases serotonin. Furthermore, we will also discuss related research findings, sources of tryptophan, the benefits of increased serotonin levels, and precautions to be considered while using tryptophan.

Does tryptophan increase serotonin?

Yes, tryptophan increases serotonin. Tryptophan is an essential amino acid that can not be synthesized by the human body, but it is an important constituent of the human diet. Tryptophan can be obtained through tryptophan-rich diets or supplements. 

Tryptophan is converted primarily to serotonin and melatonin when taken through diets or supplements. The levels of tryptophan can also be used in clinical settings to diagnose various cognitive disorders by healthcare professionals.

Tryptophan supplements are used to treat anxiety, depression, and sleep disorders (1). Serotonin, a chemical neurotransmitter found in the synaptic regions of the brain regulates sleep, mood, behaviour, appetite, emotions, and the body’s response in stressful conditions (2). 

What does research suggest about tryptophan’s effect on serotonin?

According to a research study, it was found that tryptophan, the precursor of serotonin is directly associated with anxiety and depression. When tryptophan was administered to depressed patients in a dose of 0.14 to 3gm, along with tryptophan-rich foods, it improved the mood and decreased anxiety in the research participants (3). 

Another research study suggested that the availability of tryptophan is directly linked to serotonin synthesis. When there is a deficiency of tryptophan in plasma levels, patients may experience cognitive issues. Tryptophan can also be used to treat various psychological disorders especially when used in combination with other medications (4). 

What are the sources of tryptophan?

Tryptophan is available in tryptophan-rich diets or supplements. The common food sources of tryptophan may include oats, bread, cheese, eggs, chicken, turkey, tuna fish, nuts, bananas, chocolate, and milk (4).

Tryptophan is also available in the form of supplements that can be used to treat cognitive issues such as anxiety, depression, and sleep disorders. The usual adult dose of tryptophan is 60mg taken for 3 months. However, your healthcare provider will determine the most suitable dose and duration as per your specific needs (5).

If you are taking tryptophan-rich foods along with supplements, be careful that you do not exceed the recommended limits, because higher levels of tryptophan may cause some gastrointestinal adverse effects such as nausea, vomiting, diarrhoea, constipation, or abdominal pain (5).

If you are taking tryptophan supplements along with other medications that may increase serotonin, such as Celexa, Luvox etc., they may increase serotonin levels excessively. These high levels of serotonin may pose a risk of serotonin syndrome. Serotonin syndrome is a rare but life-threatening condition. If you have any concerns regarding your supplements, please contact your healthcare provider (6). 

What are the benefits of increased serotonin levels caused by tryptophan?

The benefits of increased serotonin levels are mentioned below: 

  • Increased serotonin levels caused by tryptophan, improve the sleep-wake cycle and promote quality sleep. 
  • Higher serotonin levels may enhance the mood and behaviours of depressed individuals. 
  • Serotonin when available at sufficient levels, relieves the symptoms of stress and anxiety. 
  • Serotonin may also play a role in cognitive functions, therefore its increased levels may cause improved memory, concentration, or learning. 
  • Appetite control is another function of increased levels of serotonin. 
  • Serotonin may also affect various other biological processes in the human body (2).

What precautions should be taken while using tryptophan supplements?

The precautions that should be taken while consuming tryptophan supplements may include: 

  • You should only take tryptophan supplements after consulting your healthcare provider. 
  • Your doctor should be aware of your family or medical history, and any underlying health condition. 
  • Inform your doctor if you are taking any other medicines or supplements. 
  • Tryptophan supplements should not be used by pregnant women and nursing mothers (5).

In my opinion, tryptophan increases serotonin, as it is directly linked to serotonin synthesis in the human body. Tryptophan can not be synthesized in the human body, therefore, it has to be taken through tryptophan-rich food sources or supplements. Increased serotonin levels are associatd with overall improved cognitive functions. 

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Young SN. How to increase serotonin in the human brain without drugs. J Psychiatry Neurosci. 2007 Nov;32(6):394-9. PMID: 18043762; PMCID: PMC2077351. Available from:


Bamalan OA, Moore MJ, Al Khalili Y. Physiology, Serotonin. 2023 Jul 30. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan–. PMID: 31424752. Available from:


Kikuchi AM, Tanabe A, Iwahori Y. A systematic review of the effect of L-tryptophan supplementation on mood and emotional functioning. J Diet Suppl. 2021;18(3):316-333. doi: 10.1080/19390211.2020.1746725. Epub 2020 Apr 10. PMID: 32272859. Available from:


Dawn M Richard, Michael A Dawes, Charles W Mathias, Ashley Acheson, Nathalie Hill-Kapturczak, and Donald M Dougherty. L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications. PMCID: PMC2908021. NIHMSID: NIHMS104762. PMID: 20651948. Available from:


L-Tryptophan-MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US); [Last reviewed – 05/12/2023]. Available from:


Foong AL, Grindrod KA, Patel T, Kellar J. Demystifying serotonin syndrome (or serotonin toxicity). Can Fam Physician. 2018 Oct;64(10):720-727. PMID: 30315014; PMCID: PMC6184959. Available from: