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Medicines and supplements

L-tryptophan and sertraline: what the label and NIH say

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Ask your pharmacist or doctor before combining. The sertraline label lists tryptophan among the serotonergic drugs that raise the risk of serotonin syndrome, a reaction that can be life-threatening, and MedlinePlus names tryptophan among the nonprescription products that may interact with sertraline.1,2

Key facts

  • In its drug interaction table, the sertraline label tells prescribers to monitor for serotonin syndrome when serotonergic drugs such as tryptophan are added.1
  • The label's medication guide asks people to tell their healthcare provider if they take tryptophan.1
  • MedlinePlus says not to start tryptophan while taking sertraline without discussing it with your healthcare provider.2
  • NIH's center for complementary health warns that L-tryptophan with medicines affecting serotonin may cause life-threatening serotonin toxicity.3

Ask your pharmacist or doctor first

The sertraline label lists tryptophan among the serotonergic drugs that raise the risk of serotonin syndrome when taken with sertraline, and tells prescribers to monitor for it. MedlinePlus names tryptophan among the nonprescription products that may interact with sertraline, and NIH warns that L-tryptophan taken with medicines that affect serotonin may cause life-threatening serotonin toxicity.1,2,3

On the medicine's label

What the sertraline label says

The warning is printed on the medicine's own label. In its section on serotonin syndrome, the label says the risk rises when sertraline is used with other serotonergic drugs and names tryptophan among them, along with triptans, tricyclic antidepressants, tramadol, lithium, buspirone and St. John's wort. Its interaction table repeats the point and asks prescribers to watch for symptoms, especially when sertraline is started or its dose is raised.1

The label does not say the two can never be combined. It says that if combining serotonergic drugs is clinically warranted, patients should be told about the increased risk and watched for symptoms. That decision belongs to your prescriber, not to a supplement page.1

What MedlinePlus says

MedlinePlus, the National Library of Medicine's consumer guide to medicines, lists tryptophan with St. John's wort and some over-the-counter pain relievers as products that may interact with sertraline. It asks you to tell your doctor and pharmacist about them before starting sertraline, and not to start any of them while on sertraline without discussing it first.2

Why the two add up

Sertraline works by keeping more serotonin available between nerve cells. Tryptophan is the raw material the body makes serotonin from, and a supplement raises how much is produced. Together they can push serotonin activity too high, which is what serotonin syndrome is.1,4

Signs that need medical help

  • Changes in the mind: agitation, confusion or hallucinations1,2
  • Body signs: fever, heavy sweating, shivering or a fast heartbeat1,2
  • Muscle signs: twitching, stiffness or loss of coordination1,2
  • Stomach signs: nausea, vomiting or diarrhea1,2

MedlinePlus tells people taking sertraline to call their doctor immediately if these appear. If you notice them after combining sertraline with tryptophan, get medical help straight away.2

What to ask your pharmacist

  • Should I take tryptophan at all while I am on sertraline?
  • Do any of my other supplements, such as a sleep or mood blend, contain tryptophan or St. John's wort?
  • Which of my other medicines also raise serotonin?
  • Which signs should make me stop and call you?

Bring the Supplement Facts panel of everything you take. Tryptophan can be one of several ingredients in a blend, listed as L-tryptophan.

Questions people ask

Can I take L-tryptophan with sertraline?

Only your doctor or pharmacist can answer that for you. The sertraline label lists tryptophan as a combination that raises the risk of serotonin syndrome and calls for monitoring, so do not start it on your own.1

Does a small amount of tryptophan matter?

The label names tryptophan without setting any amount, and this page does not give one either. Ask your pharmacist about the exact product and amount.1

What about tryptophan in food?

The label and MedlinePlus refer to tryptophan as a drug or nonprescription product, alongside supplements such as St. John's wort, and do not mention food. If you are unsure, ask your pharmacist.1,2

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Sources

  1. Sertraline hydrochloride tablets: prescribing information (Cipla USA Inc.). DailyMed, U.S. National Library of Medicine. Published June 23, 2026. Opened 2026-10-07.
  2. MedlinePlus Drug Information. Sertraline. U.S. National Library of Medicine. Last revised October 15, 2025. Opened 2026-10-07.
  3. National Center for Complementary and Integrative Health. Sleep Disorders and Complementary Health Approaches. Bethesda (MD): National Institutes of Health. Last updated May 2024. Opened 2026-10-07.
  4. Fernstrom JD. Effects and side effects associated with the non-nutritional use of tryptophan by humans. J Nutr. 2012;142(12):2236S-2244S. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.