Tryptophan—An Unassuming Amino Acid With a Remarkable Effect on Sleep and Brain Health!

Tryptophan—An Unassuming Amino Acid With a Remarkable Effect on Sleep and Brain Health!

Sleep plays a major role in how we face daily challenges, and there are certain nutrients that help us get better sleep. Tryptophan is one of then. Not only does this unassuming nutrient promote quality sleep, it plays a significant role in brain health! For example, did you know that tryptophan improves learning ability? Because it’s an essential amino acid, we need to get it from food, but we don’t always get enough. Why? And what does tryptophan deficiency mean for the body? What are the best ways to get it? Together let’s take a closer look at this fascinating nutrient!

Tryptophan is an essential amino acid and part of the building blocks of proteins that are vital for optimal bodily function. In addition to being involved in protein production, it performs a full range of other functions. In particular, it is essential to production of important substances like serotonin (a neurotransmitter also known as the “happy hormone”), melatonin (a hormone that affects our sleep-wake cycle), and vitamin B3 (niacin, which plays a role in the maintenance of normal bodily growth and energy levels, regulates hormone synthesis, supports fat metabolism, and helps reduce LDL cholesterol and triglycerides). So, it definitely deserves our attention!

Having mood swings? Maybe you’re deficient in tryptophan.

As aforementioned, tryptophan is essential to the production of serotonin. Deficiency thereof is associated with a number of mental illnesses, including anxiety, depression, addiction, and schizophrenia. It is also responsible for vasoconstriction (contraction of blood vessels), increases the permeability of vascular capillaries, promotes gastrointestinal motility, halts the secretion of gastric juices, and promotes the production and excretion of substances favourable to digestion. 

Simply put, after tryptophan is consumed, it is converted by vitamin B6 into a molecule called 5-hydroxytryptophan (5-HTP), which is crucial for the biosynthesis of both serotonin and melatonin. 5-HTP is not found in food itself, so if there isn’t enough tryptophan in your diet, your body won’t be able to produce enough 5-HTP or serotonin.

What’s interesting is that more than 90% of serotonin is produced in the cells of the gastrointestinal tract, where it promotes proper central nervous system function and digestion via a 2-way communication channel: the gut-brain axis. For more on this topic, please see our blog about how intestinal health affects brain function.

Italian scientist Vittorio Erspamer discovered serotonin in 1935 while studying the contractile properties of smooth muscle in the skin, digestive tracts, and hearts of various species of animals. The neurotransmitter was found to cause changes in smooth muscle tension (the name comes from the fact that it is a serum agent that affects tone). Serotonin was not discovered in the mammalian central nervous system, however, until 1953, by American biochemist Betty Twarog.

The importance of serotonin for health has been confirmed by a number of studies. In 2021, the Journal of Psychiatry Research published a scientific paper which revealed that balancing tryptophan levels could protect against anxiety in people with panic disorders. There is also a growing body of evidence suggesting that serotonin affects learning processes. A study published by Dutch researchers in Psychopharmacology found that low levels of tryptophan (and therefore serotonin) have a negative impact on long-term memory. 

Overall, we can say that the conversion of tryptophan into serotonin is responsible for several positive effects on physical health, emotional health, and learning. Serotonin is also converted into another important substance: melatonin—a hormone responsible for our sleep-wake cycles. 

The relationship between tryptophan, melatonin, and circadian rhythm

Melatonin is a hormone produced mainly at night. It is produced by the pineal gland, but it is also found in the eyes, bone marrow, genitals, and intestines. Melatonin is often called the “sleep hormone,” because when we have high levels of it our bodies slow down and sleep better. A 2019 study by Phillips found that sleep deprivation is a problem for as many as 62% of adults worldwide, with nearly 44% of respondents saying that their sleep quality has deteriorated over the past five years. 

It’s no surprise that poor sleep can have serious health consequences, including reduced metabolism and immunity. Long-term sleep deprivation can lead to exhaustion, reduced productivity, increased risk of high blood pressure and diabetes, and may even contribute to anxiety and depression.

How is it possible that melatonin can have such a great impact on sleep? It works together with your circadian rhythm. When it gets dark, the body automatically increases melatonin production. The hormone then binds to receptors in the brain that help reduce nerve activity, sending a signal to the body that it’s time to go to bed. In response, the body begins blocking the production of dopamine—a neurotransmitter that helps you stay awake. Melatonin also stimulates the production of hormones that regulate digestion, menstruation, and many other bodily processes.

Put simply, melatonin levels affect your body’s internal clock, i.e. your feeling for when it’s time to go to sleep, wake up, and eat. These are some of our most basic bodily functions.

There are many things that can cause low melatonin levels. Among them are stress, smoking, exposure to too much light at night, lack of natural light during the day, and ageing. So, how can we make sure our bodies are getting enough? We don’t get melatonin (or serotonin) directly from our diet. So, we need to get enough tryptophan!

Drink Mana and forget about the rest!

Your tryptophan levels depend on how much and what kind of protein you consume. The richest sources of it are animal proteins, including poultry, shrimp, eggs, salmon, and milk. But there are also effective plant alternatives.

According to a study published in SAGE Journals, the recommended daily dose of tryptophan for the average adult is 350 mg per day. The same study states that the average adult gets about 950 mg per day from a normal diet. Yet this applies to omnivores. Vegetarians and especially vegans are at risk of tryptophan deficiency. Vegetarians can get their tryptophan from eggs or dairy products, but vegans may have a harder time.

For vegans, the richest sources of tryptophan are tofu, boiled soybeans, pumpkin seeds, and oats. Or even better—Mana! One serving of ManaPowder delivers around 280 mg, while one ManaDrink delivers around 200 mg. This means that 2 servings of Mana throughout the day will give you more than enough tryptophan!

But Mana is an excellent source of much, much more than tryptophan. Thanks to its nutritionally perfect composition, it’s a complete food that delivers high-quality protein with a full and balanced spectrum of amino acids, complex carbohydrates, healthy fats and omega-3s, soluble and insoluble fiber, and 14 essential vitamins and 17 essential minerals. Altogether, it contains 42 essential nutrients that your body wants and needs!

You won’t have to worry about what foods to eat or in what proportions again!



[1] K. Schruers, T. Klaasen, H. Pols, T. Overbeek, N. E. P. Deutz, E. Griez (2000) Effects of tryptophan depletion on carbon dioxide provoked panic in panic disorder patients.

[2] Shih-Hsien Lin, Lan-Ting Lee, Yen Kuang Yang (2014) Serotonin and Mental Disorders: A Concise Review on Molecular Neuroimaging Evidence.

[3] W. J. Riedel, T. Klaassen, N. E. P. Deutz, A. van Someren, Herman M. van Praag (1999) Tryptophan depletion in normal volunteers produces selective impairment in memory consolidation.

[4] Joseph A. Hanson, Martin R. Huecker (2021) Sleep Deprivation.

[5] Singlecare (2021) Sleep statistics 2021.

[6] D. M. Richard, M. A. Dawes, Charles W. Mathias, Ashley Acheson, N. Hill-Kapturczak, D. M. Dougherty (2009) L-Tryptophan: Basic Metabolic Functions, Behavioral Research and Therapeutic Indications.

[7] Hormone Health (2018) What is Serotonin?

[8] The Plant Way. 10 Plant-Based Tryptophan Foods That Skyrocket Your Serotonin.

[9] Mendel Friedman (2018) Analysis, Nutrition, and Health Benefits of Tryptophan.

[10] Grant Tinsley, PhD (2018) How Tryptophan Boosts Your Sleep Quality and Mood.

[11] Daisy Whitbread (2021) Top 10 Foods Highest in Tryptophan.

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