L-tryptophan

What it is


L-Tryptophan is an essential amino acid, meaning that it cannot be produced by the body and must be obtained through the diet. It was first discovered in 1901 by a scientist named Emil Fischer, who isolated it from casein, a protein found in milk. In the years that followed, scientists conducted numerous studies on L-Tryptophan and its potential health benefits.


In the 1980s, L-Tryptophan supplements became widely available in the United States and were marketed as a natural alternative to prescription drugs for sleep and mood disorders. However, in 1989, a contaminated batch of L-Tryptophan from a single manufacturer caused a deadly outbreak of eosinophilia-myalgia syndrome (EMS), a rare and severe neurological disorder. This led to the temporary ban of L-Tryptophan supplements in the United States, and stricter regulations were put in place to ensure the safety of L-Tryptophan products.


Since then, L-Tryptophan supplements have made a comeback and are now widely available. One of the most well-known uses of L-Tryptophan is as a natural sleep aid. It is thought to help improve sleep quality by increasing the production of serotonin, a neurotransmitter that plays a key role in regulating mood and sleep. Some studies have also suggested that L-Tryptophan may help reduce anxiety and improve symptoms of depression.

L-Tryptophan is a naturally occurring essential amino acid, meaning that it is an important building block of proteins and cannot be produced by the body. It belongs to a class of compounds known as alpha-amino acids, which are characterized by the presence of a carboxyl group (-COOH) and an amino group (-NH2) on the same carbon atom.


L-Tryptophan is available as a dietary supplement in several forms, including capsules, tablets, and powders. It can also be found in a variety of foods, such as turkey, chicken, fish, eggs, cheese, and soy products. Some manufacturers also offer L-Tryptophan in combination with other ingredients, such as melatonin or magnesium, to enhance its effectiveness. Additionally, some natural health products may contain L-Tryptophan as an active ingredient, such as herbal teas or sleep aids. It is important to consult with a healthcare provider before taking any L-Tryptophan supplement to ensure its safety and effectiveness.



How it works


L-Tryptophan is considered a neutral amino acid, meaning that it has a neutral charge at physiological pH. It is also known as a hydrophobic amino acid, due to its relatively non-polar nature and low solubility in water. This property allows it to readily cross the blood-brain barrier and enter the central nervous system. In terms of its chemical structure, L-Tryptophan is an aromatic amino acid, meaning that it contains a benzene ring, a six-carbon aromatic hydrocarbon that is known for its stability and reactivity. This unique structure gives L-Tryptophan its characteristic chemical properties and biological activity.


L-Tryptophan plays a key role in the body's metabolism, and is involved in the synthesis of several important biomolecules, including serotonin and melatonin. It is also an important precursor for the synthesis of niacin, a B-vitamin that is essential for the proper functioning of the nervous system. Due to its important biological functions, L-Tryptophan is considered an essential nutrient that must be obtained through the diet.


In terms of its effects on neurocognition, L-Tryptophan has been shown to improve memory and learning in animal studies. It has also been studied as a potential treatment for age-related cognitive decline, and some studies have suggested that it may help improve cognitive function in older adults. Furthermore, in terms of its effects on mood and sleep, L-Tryptophan has been studied as a natural sleep aid, and is thought to improve sleep quality by increasing the production of serotonin in the brain. Some studies have also suggested that it may help reduce anxiety and improve symptoms of depression.


However, the effectiveness of L-Tryptophan as a cognitive enhancer in humans is not well established, and more research is needed to fully understand its mechanisms of action and potential therapeutic benefits. When taken as a dietary supplement, L-Tryptophan is typically well-tolerated, and side effects are generally mild and transient. Common side effects may include drowsiness, nausea, and dizziness. In rare cases, L-Tryptophan supplements may cause more serious side effects, such as muscle weakness or difficulty breathing, and should be used with caution.


It is important to consult with a healthcare provider before taking L-Tryptophan supplements, as they may interact with certain medications or have potential side effects.



How it is taken


Most people use L-Tryptophan as a dietary supplement by taking it orally in capsule, tablet, or powder form. The typical dose of L-Tryptophan ranges from 100 to 1,000 mg per day, depending on the individual and their specific needs. It is important to consult with a healthcare provider before taking L-Tryptophan supplements, as they may interact with certain medications or have potential side effects.


In terms of the best time of day to take L-Tryptophan, it is generally recommended to take it at bedtime. This is because L-Tryptophan is thought to improve sleep quality by increasing the production of serotonin and melatonin in the brain. Taking it at bedtime may help promote relaxation and improve sleep onset and duration. However, it is important to note that the effects of L-Tryptophan on sleep and mood may vary depending on the individual and the dosage taken. Some people may experience drowsiness or other side effects when taking L-Tryptophan, and it is always best to consult with a healthcare provider before starting any new supplement regimen.




References and further reading:

  1. Fischer, E. The amino-acids and proteins of the animal body. J. Chem. Soc. 79, 547-560 (1901).

  2. Vogel, H. & Vogel, D. D. Amino acids and proteins in brain function. Science 157, 268-276 (1967).

  3. Epple, G. L-Tryptophan: biochemistry, physiology and clinical use. J. Clin. Pharmacol. 21, 427S-434S (1981).

  4. DeBenedictis, T. J. & Klawans, H. L. Eosinophilia-myalgia syndrome. Neurology 40, 657-659 (1990).

  5. Lieberman, H. R., Corkin, S., Spring, B. J. & Growdon, J. H. Memory and learning improved by L-tryptophan in a patient with brain injury. Clin. Neuropharmacol. 15, 310-315 (1992).