What Is Tryptophan? Things You Should Know Update 05/2024

L-tryptophan is an important amino acid used by the body to make serotonin among other things. There’s a hormone in the brain called serotonin that regulates how we feel.

Although L-tryptophan supplements have shown promise in treating anxiety and sleep problems, further evidence is needed to confirm their efficacy.

The effectiveness and safety of L-tryptophan supplements are discussed.

What is L-tryptophan?

The amino acid L-tryptophan, sometimes known as tryptophan, is necessary for the production of the happy hormone serotonin. The brain contains a hormone called serotonin, which is found elsewhere in the body as well. Mood, anxiety, and happiness levels are all controlled by serotonin in the brain.

Tryptophan, or L-tryptophan, is a supplement that can be taken.

Potential benefits

Some professionals believe that L-tryptophan can aid in the treatment of anxiety and sleep disorders due to its role in serotonin generation in the brain. Some evidence exists to back up its application in certain contexts.

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Twenty-five young individuals participated in a brief study that found that adding extra L-tryptophan to their diets improved their mood. Depression and anxiety were also alleviated.

Low L-tryptophan levels have been linked to depression and anxiety in rodents, according to a 2016 analysis.

The human authors noticed that those at most danger are those who already have a predisposition for depression. There is some evidence that suggests people who are already at risk could benefit from even slightly higher tryptophan levels.


According to the results of a 2016 study (Reliable Source) conducted on young people undergoing drug detox, the psychological symptoms experienced by these individuals improved very little, if at all.

They did, however, find that L-tryptophan was helpful in getting people to sleep during detox. Researchers cautioned that more research is needed to confirm the treatment’s potential benefits.

Premenstrual dysphoric disorder

An previous study (which should be treated with caution due to its age) found that L-tryptophan helped reduce PMDD-related pain. The study also indicated that premenstrual syndrome symptoms were more severe in participants whose diets contained little to none of the amino acid (PMS).

Pain tolerance

The impact of L-tryptophan on pain tolerance was investigated in a 2017 study (Reliable Source). The research concluded that increased amounts of this amino acid reduced perceived pain.

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Side effects

L-tryptophan is safe for human consumption when included in a balanced diet. Minor adverse effects have been reported in people taking it as a supplement.

One study (a Trusted Source) lists the following as examples of moderate but common adverse effects:

  • nausea
  • tremor
  • sleepiness (in those not taking it for sleep disorders)
  • dizziness


Serotonin syndrome is rare, although it can occur if a person takes numerous antidepressants or anxiety drugs at once.

The combination of an L-tryptophan supplement and drugs that affect serotonin levels, such as antidepressants, increases the risk of a serious condition known as serotonin syndrome.

Serotonin syndrome signs could include:

  • coma
  • involuntary twitching or jerking
  • delirium
  • hyperthermia

A temporary association between tryptophan supplements and eosinophilia myalgia syndrome was reported in 1989 (Reliable Source) (EMS). Muscle soreness to the point of disability and an elevated peripheral eosinophil count are both indications of EMS. EMS was traced back to a defective batch of the supplement, rather than the supplement itself.

It’s also worth noting that dietary supplements are not presently regulated by the Food and Drug Administration (FDA).

However, there are a number of third-party labs that examine supplements for quality and safety. If you want to reduce your chances of buying a subpar product or one that doesn’t work, it’s best to opt for supplements that have been evaluated and approved by impartial authorities.

Other sources

Many foods include L-tryptophan as an ingredient. Here are a few examples of potential food sources:

  • turkey
  • tuna
  • nuts
  • seeds
  • bananas
  • dairy products
  • red meat
  • shellfish
  • soy products

The amount of the vitamin in food probably won’t have any influence, either positive or bad, on a person’s sleep or mood.

Tryptophan - ChemicalSafetyFacts.org

Alternatives to L-tryptophan

Supplemental melatonin is another option for those seeking relief from sleeplessness. The hormone melatonin helps regulate sleep patterns and wakefulness.

Alternative sleep aids that don’t include supplements are also an option. Among the measures that have the potential to improve sleep quality are:

  • Taking a warm milk drink.
  • Maintaining a comfortable temperature and complete darkness in the bedroom.
  • Getting your workout in during the workday.

If you have any additional health concerns and are thinking about taking L-tryptophan for treatment, you should discuss this with your doctor first.

When to see a doctor

Before using any supplement, people should see their doctor. Antidepressant patients in particular should consult a medical professional before beginning L-tryptophan supplementation.

If someone taking the supplement experiences any kind of adverse reaction, they should stop taking it immediately and consult a medical professional.


The amino acid L-tryptophan has been studied for its potential as a sleep aid, as well as its potential to alleviate symptoms of chronic pain, anxiety, sadness, and premenstrual syndrome (PMS).

However, the supplement might not work for everyone and might not improve everything. People should consult their physician before beginning a new supplement regimen, and should discontinue use if adverse reactions occur.

L-tryptophan may be helpful in alleviating some of these symptoms, but further research is needed to confirm this.

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