L-tryptophan (Tryptan)

What is tryptophan capsule, tablet, and how does it work (mechanism of action)?

L-tryptophan is an herbal supplement used for depression. Chemically it is a natural occurring amino acid obtained from plants and animals. L-tryptophan is an "essential" amino acid because humans cannot make it and must obtain L-tryptophan from food. It is converted in the body to serotonin. People with depression have an imbalance of serotonin and other brain chemicals. Increased serotonin levels in the brain improve symptoms of depression.

What brand names are available for tryptophan capsule, tablet?

Tryptophan, Tryptan

Is tryptophan capsule, tablet available as a generic drug?


Do I need a prescription for tryptophan capsule, tablet?


What are the side effects of tryptophan capsule, tablet?

Side effects of L-tryptophan are:

What is the dosage for tryptophan capsule, tablet?

  • Adults: Take 8 to 12 grams of L-tryptophan by mouth per day. L-tryptophan should be taken in divided doses of three or four times a day.
  • Pediatric: Safe and effective use in pediatric patients is not determined.

Which drugs or supplements interact with tryptophan capsule, tablet?

L-tryptophan should be used with caution with other anti-depressants like citalopram (Celexa), desvenlafaxine (Pristiq), vilazodone, linezolid, and phenelzine because of increased risk of a serious condition called serotonin syndrome caused by excessive serotonin in the brain.


Sleep Disorders: Foods That Help Sleep or Keep You Awake See Slideshow

Is tryptophan capsule, tablet safe to take if I'm pregnant or breastfeeding?

There are no adequate studies done on L-tryptophan to determine safe and effective use in pregnant women.

It is not known whether L-tryptophan enters breast milk; however, it is best to avoid L-tryptophan during breastfeeding to avoid risk to the newborn.

What else should I know about tryptophan capsule, tablet?

What preparations of tryptophan capsule, tablet are available?

L-tryptophan is available in 500 mg and 1000 mg tablets and capsules.

How should I keep tryptophan capsule, tablet stored?

L-tryptophan is stored in tightly closed containers. Due to multiple companies producing this medication, storage requirement may vary based on manufacturer.


L-tryptophan (Tryptophan, Tryptan) is an herbal supplement taken for depression, anxiety, sleep apnea, premenstrual syndrome (PMS), and a variety of other conditions. Side effects, drug interactions, dosage, and pregnancy safety should be reviewed prior to taking this supplement.

Treatment & Diagnosis

Medications & Supplements

Prevention & Wellness

Health Solutions From Our Sponsors

FDA Logo

Report Problems to the Food and Drug Administration

You are encouraged to report negative side effects of prescription drugs to the FDA. Visit the FDA MedWatch website or call 1-800-FDA-1088.

Medically reviewed by John P. Cunha, DO, FACOEP; Board Certified Emergency Medicine