Tryptophan is one of the 23 proteinogenic (protein building) amino acids found in nature. Humans need this nutrient as an important component to process proteins and to synthesize the neurotransmitter Serotonin.
Tryptophan is one of nine “essential” amino acids for humans. Essential amino acids are necessary for various body functions; however, the body cannot produce these compounds internally. Essential amino acids, including Tryptophan, must be obtained through the diet or dietary supplements.
Tryptophan is found in many protein rich foods, including red meat, eggs, poultry, fish, chickpeas, almonds, peanuts, cottage cheese, and milk.
However, Tryptophan is often the least plentiful amino acid in the standard North American diet. Also, research has found that increasing dietary Tryptophan is unlikely to increase Tryptophan concentrations in the blood.
Additionally, the amount of dietary Tryptophan, or its metabolites like 5-HTP, that can cross the barrier separating the bloodstream and the brain is limited. Other amino acids from food protein sources use the same transport channels across the blood-brain barrier as Tryptophan uses. This limits the amount of Tryptophan that can enter the brain.
Purified Tryptophan supplements have been shown to increase the amount of Serotonin in the brain, while eating Tryptophan rich foods does not always have an effect. As such, many individuals have started using Tryptophan supplements to increase levels of Serotonin in the brain, which may result in improved mood and better sleep patterns.
Tryptophan is not soluble in water and also possesses a notable resistance to heat, making it a very durable compound. It also has a high degree of bioavailability.
Tryptophan has nootropic qualities insofar as it may alleviate symptoms of anxiety and depression, increase restful sleep, improve focus, and balance the mood.



- Precursor for serotonin synthesis
- Supports a calm, relaxed mood
- Promotes restful sleep patterns
Tryptophan Effects
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Tryptophan is a precursor to a number of different hormones, neurotransmitters, and other substances throughout the body.
As this supplement travels through the bloodstream it aids in the production or synthesis of various proteins. Tryptophan is a precursor for Niacin, a B vitamin with several positive effects on the brain. Tryptophan is also used to make Serotonin, an important neurotransmitter.
Tryptophan is broken down in the liver into the compound 5-HTP and other metabolites. The 5-HTP travels through the bloodstream to the brain, crosses the blood-brain barrier, and enters the brain. Once in the brain, the 5-HTP is converted into Serotonin.
Serotonin is known as the “happiness neurotransmitter,” because the presence of Serotonin in the brain is associated with positive emotions including happiness, peacefulness, and calm.
Tryptophan being a precursor for Serotonin is an important function in itself, but it also leads to a number of additional effects. Serotonin is thought to help regulate things like appetite and mood. Some Serotonin is also converted to Melatonin, the hormone which regulates sleep/wake patterns (circadian rhythm).
Tryptophan Benefits
One of the key benefits of Tryptophan is that it may help to decrease appetite and reduce symptoms of depression and anxiety. Studies have shown that low levels of Tryptophan in the body may lead to anxiety disorders and depression.
It has also been shown that the Serotonin resulting from Tryptophan has a limiting effect on appetite and may help to reduce caloric intake and weight in obese people. Tryptophan is further used to synthesize Niacin, which is used in the processing of carbohydrates and fats.
Tryptophan supplementation may also encourage healthy sleep patterns. These benefits seem to be directly related to the release and synthesis of Serotonin and Melatonin. Tryptophan is capable of maintaining a fairly consistent level of Serotonin throughout the day and aids in the production of the proper level of Melatonin at night.
This makes Tryptophan distinct from the other well-known Serotonin precursor (and Tryptophan metabolite), 5-HTP. When ingested orally, 5-HTP is not subject to any rate-limiting factors, which means there is no control on how high Serotonin levels may go.
Consequently, Tryptophan’s effects may be less noticeable than 5-HTP, but with potentially fewer side effects.
There are a number of medical conditions which Tryptophan is able to improve. A 2010 study showed that Tryptophan may halt the spread of a common liver condition known as steatohepatitis.
Tryptophan may also be capable of improving conditions associated with irritable bowel syndrome (IBS). It has been shown that the less Tryptophan a person has in their body, the more serious the symptoms of this condition can be.
Tryptophan Dosage
As with most supplements, the dosage you take will be determined by your specific purpose or condition. For this reason it is advised to consult with your doctor or qualified medical professional before beginning use.
Some sources indicate that the most commonly used dosage range is between 6 and 12 grams.
Most adults (especially those who are looking to reduce symptoms of depression) will take Tryptophan supplements in 3 or 4 equally divided daily administrations to ensure a consistent supply.
Tryptophan Side Effects
When taken as directed and in the proper doses, most users can expect to experience no unusual side effects from Tryptophan.
Gastrointestinal side effects have been reported by some users though, including nausea, heartburn, vomiting, stomach pain, and diarrhea.
It is possible to suffer an overdose when Tryptophan is taken in excessive amounts. This can lead to a number of possible side effects, including: agitation, confusion, fever, overactive reflexes, restlessness, shivering, sweating, shaking, twitching, dizziness, dry mouth, or headache.
If any of these symptoms occur, it is recommended to discontinue usage immediately and contact a doctor. After the side effects pass, it is possible to re-start use with a lower dose if advised by your doctor.
Tryptophan Review
There is much to be said in favor of using Tryptophan in a nootropic stack. Dietary Tryptophan is what the body naturally uses to make Serotonin and it also plays a role in various other processes related to metabolism and health.
While some may rebuff Tryptophan supplements in favor of more powerful Serotonin precursors like 5-HTP, this compound may have notably positive effect on mood and sleep.
More importantly, Tryptophan boosts Serotonin levels without bypassing the main regulatory mechanisms that are used to keep neurotransmitter supplies in balance.
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Article last updated on: May 7th, 2018 by Nootriment
1 Comment
Tryptophan also has the benefit of taking longer to metabolize into Serotonin, which gives it more time to cross the blood-brain barrier (which Serotonin cannot) before being metabolized.
I’ve also read that Serotonin can have a deleterious effect on your heart, so ensuring the Serotonin is created in your brain rather than the rest of your body is beneficial in that way as well.