What does low tryptophan mean? (6+ signs)

In this article, we will discuss low tryptophan levels. Furthermore, we’ll explore what research suggests on this, the causes and contributing factors of low tryptophan levels, symptoms and effects of low tryptophan on the body, the risks and complications associated with it and management strategies to balance the levels.

What does low tryptophan mean? 

Low tryptophan levels refer to a condition in which the concentration or amount of tryptophan is below the normal or necessary range in the body. Tryptophan is considered an essential amino acid that your body can’t produce on its own, rather you must obtain it through your diet to meet the daily requirements of the body. (1,2)

Tryptophan plays a role in several crucial processes in the body including protein synthesis which helps in the maintenance and repair of damaged body tissues and it also serves as a precursor for serotonin synthesis which is an important neurotransmitter that regulates mood and reduces feelings of anxiety and depression. (1)

If you have any concerns about tryptophan levels or related health issues, it is advisable to consult your healthcare provider. They might help to identify and address the underlying cause of low tryptophan levels and assess further evaluation in this regard.

What does research suggest?

According to research, scientists used a method called acute tryptophan depletion (ATD) to learn how low tryptophan leads to low serotonin levels and its effects on the human brain. They found out that low serotonin levels from tryptophan depletion negatively altered the mood of individuals and increased depression in them. (2)

The researchers gave a mixture of tryptophan-free amino acids (18.2g) to healthy volunteers and found that their serum tryptophan dropped by 42%. This group also felt more anxious and restless compared to the control group who received the tryptophan mixture. (2)

Later, another team used a similar mixture without tryptophan and also removed glycine amino acid this time and found that it significantly affected the sleep of healthy individuals. 

These studies show how low levels of tryptophan in the body can affect your sleep cycle, alter mood and promote irritability and aggressive behaviour while those who were receiving adequate tryptophan supplements felt happy and relaxed with no negative changes in their mood or behaviour. (2)

What factors contribute to low tryptophan levels? 

Several factors can contribute to tryptophan deficiency in your body. Some of the key factors include: (1,3)

Dietary insufficiency: If you’re not consuming enough food rich in tryptophan composition like meat, dairy products, nuts, seeds and certain cereals or grains, this means you are taking an imbalanced diet that is deficient in overall protein content and low your tryptophan levels.

Malnutrition: General malnutrition, where the body lacks essential vitamins and nutrients may lead to low tryptophan levels. 

Competition with other amino acids: Tryptophan competes with other amino acids to cross the blood-brain barrier. If other amino acids are abundant, tryptophan may have a reduced chance of entering the brain, which will also affect serotonin production.

Digestive disorders: If your digestive system is not functioning properly due to some other conditions like malabsorption disorders, this can also influence and hinder the absorption of tryptophan from the diet. 

Increased metabolic demand: Certain conditions like chronic stress, illness or intense physical activity can heighten your body’s metabolic demand and may lead to increased utilization of tryptophan, thereby reducing its levels.

Genetic factors: Everyone is unique in terms of brain chemistry and how they respond to or process medications or natural substances in the body. Changes in genetic makeup cause diversions in the metabolism and utilization of tryptophan. 

Medications: Certain medications, especially those affecting amino acid metabolism, can influence tryptophan levels. 

Alcohol consumption: Consumption of alcohol in excessive quantity can lead to alterations of tryptophan metabolism by the liver and thus decrease levels. 

Vitamin B6 deficiency: Vitamin B6 is also responsible for the conversion of tryptophan into serotonin, so a deficiency of this vitamin may influence the conversion and activity of tryptophan. 

What are the signs and symptoms of low tryptophan levels?

Low levels of tryptophan can contribute to a variety of symptoms usually co-related with altered serotonin production in the body. The effects and symptoms may differ among individuals and include: (5)

Mood changes:

  • Depression: Tryptophan is a serotonin precursor and its low levels can contribute to depressive symptoms. 
  • Anxiety: Insufficient serotonin levels can negatively influence one’s mood and increase anxious feelings.

Sleep disturbances:

  • Insomnia: Low serotonin levels can impact your sleep patterns by disrupting the melatonin hormone, leading to difficulty falling asleep or staying asleep. 
  • Changes in sleep quality: Low levels of melatonin, a hormone which regulates your sleep-wake cycle, can affect the quality and timings of your sleeping schedule. 

Appetite changes:

  • Increased cravings: Low tryptophan levels in your body may increase the cravings for carbohydrates and sugary foods, potentially contributing to weight gain.

Cognitive Impairment: 

  • Poor concentration: Low tryptophan levels reduce the production of serotonin, a neurotransmitter which also supports cognitive functions and may lead to difficulty retaining focus and concentration. 

Digestive issues:

  • Gastrointestinal discomfort: Serotonin is also present in the gut and plays a role in digestive functions. Low levels may contribute to gastrointestinal discomfort such as abdominal pain, nausea, vomiting, diarrhoea etc.  

Migraines and headaches: 

  • Serotonin imbalance: Tryptophan plays a crucial role in maintaining serotonin levels and disruptions in this balance can lead to mild to moderate or even severe headaches and migraine. 

Niacin deficiency: 

  • Pellagra: Tryptophan serves as a precursor to make niacin (vitamin B3). Low levels may lead to niacin deficiency which can cause pellagra, a condition associated with skin, digestive and certain neurological symptoms. 

Cardiovascular effects:

  • Changes in blood pressure: Tryptophan being the precursor of serotonin can greatly influence blood pressure by constricting or dilating the blood vessels, depending on the availability of serotonin. Heart health can be compromised by alterations in tryptophan levels.


  • Low energy levels: Serotonin produced by tryptophan is also involved in energy regulation and disruptions in their levels can lead to feelings of fatigue or excessive tiredness. 

It’s important to remember that these symptoms can be influenced by various factors and not everyone experiencing tryptophan deficiency necessarily has to suffer all these symptoms, they can vary among different individuals. 

What are the management strategies for low tryptophan levels?

To balance the tryptophan levels you must address the underlying causes that might be contributing to its deficiency with the help of a doctor and ensure the adequate intake of tryptophan through your diet. (5)

Include foods rich in tryptophan in your daily routine like meat, poultry, nuts, grains etc. If dietary sources are limited or do not fulfil the sufficiency criteria then you may also switch to supplements but only under the guidance of your healthcare provider to avoid any harmful interactions or side effects. (4)

Practice some stress management techniques like regular exercise which might include running, swimming or weight lifting, and try out yoga or meditation to reduce your tension as chronic stress may also contribute to low tryptophan levels and also affect its metabolism. 

Keep yourself hydrated by drinking an adequate amount of water and try to incorporate the essential minerals and nutrients in your diet like vitamin B6 which is necessary for the conversion of tryptophan to serotonin. Fix your sleeping schedule and keep an eye on your gut health. (5)

As a pharmacist, In my opinion, adopting healthy lifestyle modification approaches and a balanced diet rich in all essential nutrients can help you complement your specific condition to a great extent. In case, you experience any aforementioned symptoms for a prolonged time and become troublesome reach out to your doctor and discuss the concerns carefully.

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National library of medicine. MedlinePlus Drug Information, Tryptophan, [Internet]. Available from: https://medlineplus.gov/ency/article/002332.htm