L-Tryptophan - What is it & How to use

L-tryptophan is naturally found in animal and plant proteins. L-tryptophan is considered an essential amino acid because our bodies can’t make it. It is important for the development and functioning of many organs in the body. After absorbing L-tryptophan from food, our bodies convert it to 5-HTP (5-hyrdoxytryptophan), and then to serotonin, melatonin, and vitamin B6 (nicotinamide). Serotonin is a hormone that transmits signals between nerve cells. It also causes blood vessels to narrow. Changes in the level of serotonin in the brain can alter mood. Melatonin is important for sleep and vitamin B6 is essential for energy metabolism.

Effectiveness

Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.

The effectiveness ratings for L-TRYPTOPHAN are as follows:

Possibly effective for…

  • Premenstrual dysphoric disorder (PMDD). Taking 6 grams of L-tryptophan per day seems to decrease mood swings, tension, and irritability in women with PMDD.
  • To help people quit smoking. Taking L-tryptophan seems to help people quit smoking when used with conventional treatment.

Possibly ineffective for…

  • Teeth grinding (bruxism). . Taking L-tryptophan by mouth doesn’t help treat teeth grinding.
  • Facial pain. Taking L-tryptophan by mouth doesn’t help reduce facial pain.

Insufficient evidence to rate effectiveness for…

  • Improving athletic ability. Some research shows that taking L-tryptophan for 3 days before exercising can improve power during exercise. This improvement in power helps increase the distance an athlete can go in the same amount of time. But other early research shows that taking L-tryptophan during exercise doesn’t improve endurance during a cycling exercise. Reasons for the conflicting results are not clear. It is possible that L-tryptophan improves some measures of athletic ability but not others. On the other hand, L-tryptophan might need to be taken for a few days before exercise in order to see any benefit.
  • Attention deficit-hyperactivity disorder (ADHD). There is some evidence that L-tryptophan levels are lower in children with ADHD. But taking L-tryptophan supplements does not appear to improve ADHD symptoms.
  • Problems with mental function in the elderly. Taking a mixture of L-tryptophan and other ingredients can slightly improve mental function in older people. But the improvement is very small, so it might not be meaningful. Also, it’s not known if any potential benefit is due to L-tryptophan or another ingredient.
  • Depression. Early research suggests that L-tryptophan might improve the effectiveness of common medications for depression.
  • Healing ulcers caused by the bacteria Helicobacter pylori (H pylori). Research shows that taking L-tryptophan in combination with the ulcer medication omeprazole improves ulcer healing rates compared to taking omeprazole alone.
  • Treating sleep disorders. Taking L-tryptophan might decrease the amount of time it takes to fall asleep and improve mood in healthy people with sleep problems.
  • Seasonal affective disorder (SAD). Early research suggests L-tryptophan might be helpful in SAD.
  • Treating sleep apnea. There is some evidence that taking L-tryptophan might decrease episodes in some people who periodically stop breathing during sleep (sleep apnea).
  • Anxiety.
  • Other conditions.

More evidence is needed to rate L-tryptophan for these uses.

Dose

The following doses have been studied in scientific research:

ADULTS

BY MOUTH:

  • Premenstrual dysphoric disorder (PMDD): Doses of 6 grams of L-tryptophan have been taken daily from ovulation to the third day of the period.
  • To help people quit smoking: Doses of 50 mg/kg of L-tryptophan have been taken daily.

Safety Concerns

L-tryptophan is POSSIBLY UNSAFE when taken by mouth as a medicine. It has been linked to over 1500 reports of eosinophilia-myalgia syndrome (EMS) and 37 deaths. EMS is a neurological condition with symptoms that include fatigue; intense muscle pain; nerve pain; skin changes; baldness; rash; and pain and swelling affecting the joints, connective tissue, lungs, heart, and liver. Symptoms tend to improve over time, but some people may still experience symptoms up to 2 years after they develop EMS. Some people report that their symptoms have never gone away completely.

In 1990, L-tryptophan was recalled from the market due to these safety concerns. After the limitation of L-tryptophan products, the number of EMS cases dropped sharply. The exact cause of EMS in patients taking L-tryptophan is unknown, but some evidence suggests it may be due to contaminated L-tryptophan products. About 95% of all EMS cases were traced to L-tryptophan produced by a single manufacturer in Japan. Currently, under the Dietary Supplement Health and Education Act (DSHEA) of 1994, L-tryptophan is available and marketed as a dietary supplement.

L-tryptophan can cause some side effects such as heartburn, stomach pain, belching and gas, nausea, vomiting, diarrhea, and loss of appetite. It can also cause headache, lightheadedness, drowsiness, dry mouth, visual blurring, muscle weakness, and sexual problems.

Special precautions & warnings:

Pregnancy and breast-feeding: L-tryptophan is LIKELY UNSAFE in pregnancy because it may harm the unborn child. Not enough is known about the safety of L-tryptophan during breast-feeding. Avoid using L-tryptophan during pregnancy and breast-feeding.

A white blood cell disorder called eosinophilia: L-tryptophan might make this condition worse. L-tryptophan has been associated with the development of eosinophilia-myalgia syndrome (EMS).

Liver or kidney disease: L-tryptophan might make these conditions worse since it has been associated with the development of eosinophilia-myalgia syndrome (EMS).

Interaction with medication

Major
Do not take this combination.
Sedative medications (CNS depressants)
L-tryptophan might cause sleepiness and drowsiness. Medications that cause sleepiness are called sedatives. Taking L-tryptophan along with sedative medications might cause too much sleepiness.

Some sedative medications include clonazepam (Klonopin), lorazepam (Ativan), phenobarbital (Donnatal), zolpidem (Ambien), and others.

Moderate
Be cautious with this combination.
Dextromethorphan (Robitussin DM, and others)
L-tryptophan can affect a brain chemical called serotonin. Dextromethorphan (Robitussin DM, others) can also affect serotonin. Taking L-tryptophan along with dextromethorphan (Robitussin DM, others) might cause there to be too much serotonin in the brain and serious side effects including heart problems, shivering and anxiety could occur. Do not take L-tryptophan if you are taking dextromethorphan (Robitussin DM, others).
Medications for depression (Antidepressant drugs)
L-tryptophan increases a brain chemical called serotonin. Some medications for depression also increase the brain chemical serotonin. Taking L-tryptophan along with these medications for depression might increase serotonin too much and cause serious side effects including heart problems, shivering, and anxiety. Do not take L-tryptophan if you are taking medications for depression.

Some of these medications for depression include fluoxetine (Prozac), paroxetine (Paxil), sertraline (Zoloft), amitriptyline (Elavil), clomipramine (Anafranil), imipramine (Tofranil), and others.

Medications for depression (MAOIs)
L-tryptophan increases a chemical in the brain. This chemical is called serotonin. Some medications used for depression also increase serotonin. Taking L-tryptophan with these medications used for depression might cause there to be too much serotonin. This could cause serious side effects including heart problems, shivering, and anxiety.

Some of these medications used for depression include phenelzine (Nardil), tranylcypromine (Parnate), and others.

Meperidine (Demerol)
L-tryptophan increases a chemical in the brain called serotonin. Meperidine (Demerol) can also increase serotonin in the brain. Taking L-tryptophan along with meperidine (Demerol) might cause too much serotonin in the brain and serious side effects including heart problems, shivering, and anxiety.
Pentazocine (Talwin)
L-tryptophan increases a brain chemical called serotonin. Pentazocine (Talwin) also increases serotonin. Taking L-tryptophan along with pentazocine (Talwin) might cause serious side effects including heart problems, shivering, and anxiety. Do not take L-tryptophan if you are taking pentazocine (Talwin).
Phenothiazines
Taking L-tryptophan with phenothiazines can cause serious side effects including movement disorders.

Some phenothiazines include chlorpromazine (Thorazine), fluphenazine (Prolixin), trifluoperazine (Stelazine), thioridazine (Mellaril), and others.

Sedative medications (Benzodiazepines)
Sedative medications can affect the nervous system. L-tryptophan can also affect the nervous system. Taking L-tryptophan along with sedative medications can cause serious side effects. Do not take L-tryptophan if you are taking sedative medications.

Some of these sedative medications include clonazepam (Klonopin), diazepam (Valium), lorazepam (Ativan), and others.

Tramadol (Ultram)
Tramadol (Ultram) can affect a chemical in the brain called serotonin. L-tryptophan can also affect serotonin. Taking L-tryptophan along with tramadol (Ultram) might cause too much serotonin in the brain and side effects including confusion, shivering, and stiff muscles could result.

* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.