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Dietary supplement

L-Tryptophan 500 mg Ingredients & Drug Interactions

by Jarrow Formulas

Capsule Category: Amino Acid/protein
Most serious interaction: Major
The interaction bottom line Most serious interaction: Major

L-Tryptophan 500 mg is a dietary supplement by Jarrow Formulas with 1 active ingredient. Its ingredients are commonly taken for sleep problems, low mood and depression, anxiety.Based on those ingredients, 394 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are L-Tryptophan. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of L-Tryptophan 500 mg by Jarrow Formulas

Our pharmacy team’s full take, with four database checks built into the cards below — a summary of what is known, not a grade of the product itself.

From our pharmacy team — supplement deep dive

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This supplement contains one active ingredient: L-tryptophan, an amino acid your body uses to make serotonin, a brain chemical involved in mood and sleep. The capsule also holds inactive ingredients — microcrystalline cellulose, hydroxypropyl methylcellulose, magnesium stearate, silicon dioxide, and water — which are fillers and binders that don't add therapeutic value.

Does it work?

Not established
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Not established

The graded evidence we hold for these ingredients covers different conditions than the ones this product is marketed for, so there's no established rating for its stated use — see L-tryptophan's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: sleep support.
  • We looked for evidence on: insomnia, sleeplessness, sleep quality.
  • The closest evidence on file: L-tryptophan is rated "Insufficient Reliable Evidence To Rate" for Insomnia (Natural Medicines).

The evidence for L-tryptophan in depression is rated possibly ineffective based on the data we hold. For anxiety, athletic performance, teeth grinding (bruxism), and premenstrual dysphoric disorder, there isn't enough reliable evidence to rate whether it works.

If you're considering it for any of these uses, talk with your doctor about whether it's right for you.

The evidence, ingredient by ingredient L-tryptophan

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

L-tryptophan is generally well tolerated, though mild side effects are common: belching, diarrhea, drowsiness, dry mouth, gas, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, and vomiting. There's an important historical note: in 1989, a contaminated batch from a single Japanese manufacturer caused over 1,500 cases of a serious neurological disorder called eosinophilia-myalgia syndrome (EMS), leading to an FDA alert and recall.

Current products are not from that source, but caution is warranted. The safety data advises against use during pregnancy and breastfeeding — there isn't enough evidence to know it's safe in either situation, so talk with your doctor or pharmacist before taking it if you're pregnant, planning pregnancy, or breastfeeding.

Side effects, ingredient by ingredient L-tryptophan

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — L-tryptophan.
  • The most serious interaction on file is rated Major.
  • For scale: 394 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

Before taking this product, check with your doctor or pharmacist if you take any CNS depressants — sedatives, sleep aids, opioids, or other drugs that slow your nervous system — or any serotonergic drugs, including most antidepressants, some migraine medications, and certain pain relievers. These carry Major and Moderate interaction risks, respectively.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Major medication interactions have been identified, and safety information is well characterized.

L-Tryptophan may appeal to you if you're interested in a natural approach to mood or sleep, but the evidence for depression is weak and for other uses it's unproven. It's not right for you if you take CNS depressants or serotonergic drugs like most antidepressants without clearing it first.

Check with your own doctor or pharmacist before starting, especially if you're on any psychiatric or pain medication.

Educational only — not medical advice; always confirm with your pharmacist. Our editorial policy · How we use AI

Assessment coverage: 1 of 1 active ingredient matched to our full ingredient reviews (monographs). Based on the product label dated Jan 24, 2024.

This Scorecard evaluates available label information, ingredient evidence, and known medication-safety considerations. It does not independently verify product identity, purity, potency, contamination, or manufacturing quality. How these ratings are computed

At a glance

General information

Key facts about L-Tryptophan 500 mg, straight from the product label.

Brand Jarrow Formulas
Barcode (UPC) 790011150565
Net contents 60 Veggie Capsule(s)
Market status On market
Date entered into DSLD Jan 24, 2024
DSLD ID 307642
Product type Amino Acid/protein
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), No Allergies, Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for L-Tryptophan 500 mg by Jarrow Formulas, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
60
UPC/BARCODE
790011150565
IngredientAmount% DV
L-Tryptophan500 mg--

Other ingredients: Hydroxypropyl Methylcellulose, Water, Magnesium Stearate, Microcrystalline Cellulose, Silicon Dioxide

Tap any ingredient to jump to its full detail below.

Label statements
These statements are the manufacturer’s wording, reproduced from the product label — the label is saying it, not HelloPharmacist. We don’t verify or endorse them.
Suggested/Recommended/Usage/Directions

Suggested Use: Adults take 1 capsule once a day on an empty stomach 30 minutes before sleep with water or fruit juice or as directed by your qualified healthcare professional.

Formula

Jarrow Formulas L-tryptophan is an essential amino acid that cannot be synthesized by the body, but must be obtained from food or supplements. L-tryptophan is converted to serotonin (5-hydroxytryptamine) and melatonin in the body, which plays an important role in supporting a balanced mood and restful sleep.

Precautions

Warning: Do not take this product if you are taking any SSRIs (selective serotonin reuptake inhibitors) or MAOIs (monoamine oxidase inhibitors). Consult a healthcare professional before using this product if you are trying to conceive, pregnant, or lactating, under the age of 18, or have a medical condition; if adverse reactions occur, discontinue use.

Consult a healthcare professional before using this product if you are trying to conceive, pregnant, or lactating, under the age of 18, or have a medical condition; if adverse reactions occur, discontinue use. Keep out of the reach of children.

This product is for occasional sleeplessness. Do not use if safety seal is damaged or missing.

Storage

Store in a cool, dry place.

FDA Disclaimer Statement

These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.

Formulation

Vegan

Relaxation Supports production of serotonin (relaxation, balanced mood) & melatonin (sleep)

Gluten free

No wheat, gluten, soybeans, dairy, egg, fish/shellfish, peanuts/tree nuts or sesame. IGEN Non-GMO tested

FDA Statement of Identity

Dietary Supplement

Seals/Symbols

IGEN Non-GMO tested

Brand IP Statement(s)

Copyright 2023 Jarrow Formulas

General Statements

Sleep support

See for yourself

L-Tryptophan 500 mg by Jarrow Formulas label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

What’s inside

The Ingredients in L-Tryptophan 500 mg by Jarrow Formulas

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size1 Capsule(s) Dosage formCapsule Servings per container60 Amounts shown are per serving.

L-Tryptophan

Interacts with
394 drugs
500 mg per serving

L-tryptophan is an essential amino acid the body uses to make serotonin and melatonin, and people take it to support sleep and mood. The evidence for...

L-Tryptophan monograph & interactions

Other (inactive) ingredients: Hydroxypropyl Methylcellulose, Water, Magnesium Stearate, Microcrystalline Cellulose, Silicon Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Tryptophan 500 mg by Jarrow Formulas Drug Interactions

Want to check YOUR meds against L-Tryptophan 500 mg?

Ask about interactions with your drugs in plain English — “Can I take it with lisinopril?” — and we find you the answer in seconds, ingredient by ingredient.

Go to the checker
394Drugs
248 Major 146 Moderate

Ingredients driving the most interactions

Each ingredient & the kinds of drugs it affects

For each ingredient in L-Tryptophan 500 mg with known interactions, here are the types of medications it can affect. Open any type for the detail — or search your exact drug in the checker above.

L-Tryptophan2 drug types · 394 drugs

Cns Depressants

Theoretically, concomitant use of L-tryptophan with CNS depressants might cause additive sedative effects.
Clinical research shows that L-tryptophan can cause fatigue and drowsiness.

Likelihood Probable Evidence B
Serotonergic Drugs

Theoretically, combining L-tryptophan with serotonergic drugs might cause additive serotonergic effects.
L-tryptophan is a precursor to serotonin. Theoretically, combining serotonergic drugs with L-tryptophan might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders.

Likelihood Possible Evidence D
The maker

Brand information

Manufacturer and brand details for L-Tryptophan 500 mg, from the product label.

Jarrow Formulas

See all Jarrow Formulas products
Name
Jarrow Formulas, Inc.
City
Sherman Oaks
State
CA
ZipCode
91403
Phone Number
1-866-459-4154
Web Address
www.Jarrow.com
Pharmacist Counseling Corner

L-Tryptophan 500 mg by Jarrow Formulas: Common Questions

Does L-Tryptophan 500 mg by Jarrow Formulas interact with any medications?
Yes. Based on its ingredients, L-Tryptophan 500 mg has a known interaction with 394 medications, including 248 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
L-Tryptophan 500 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this if I'm pregnant or breastfeeding?
The safety data advises against it. There isn't enough evidence to know it's safe during pregnancy or breastfeeding, so don't take it in either situation without talking to your doctor or pharmacist first.
What are the most common side effects?
Belching, diarrhea, drowsiness, dry mouth, gas, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, and vomiting. Most people tolerate it well, but these are worth knowing about.
Does L-tryptophan actually work for depression?
Based on the evidence we hold, it's rated possibly ineffective for depression. If you're dealing with depression, talk with your doctor about proven treatment options.
Is this safe given the 1989 contamination scare?
That outbreak came from a single Japanese manufacturer and has been traced and resolved. Current products aren't from that source, but the history warrants caution — which is why we mention it.
What is L-tryptophan and what does it do?
It's an amino acid — a building block your body uses to make serotonin, a brain chemical tied to mood and sleep. Your body can't make it on its own, so it comes from food or supplements.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if L-Tryptophan 500 mg is safe with your meds?

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Ask a pharmacist

Label information is sourced from the NIH Dietary Supplement Label Database and reflects the product version on file; always read your actual product label. This page is for education only and is not a substitute for professional medical advice. Confirm with your pharmacist or doctor before combining supplements and medications.

L-Tryptophan 500 mg label
Sources

Sources & How We Checked

L-Tryptophan 500 mg's label data comes from the NIH Dietary Supplement Label Database; the ingredient interaction data is from the Natural Medicines database, reviewed by our pharmacists.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

The 18 references behind this product’s interaction data

Every citation that drives the interaction findings for this product’s ingredients, from the evidence-graded Natural Medicines (TRC Healthcare) database. Open an ingredient to browse its citations — links open the study on PubMed or the publisher’s site.

L-tryptophan 18 references
  1. Messiha FS. Fluoxetine: adverse effects and drug-drug interactions. J Toxicol Clin Toxicol 1993;31:603-30. PubMed
  2. Devoe LD, Castillo RA, Searle NS. Maternal dietary substrates and human fetal biophysical activity. The effects of tryptophan and glucose on fetal breathing movements. Am J Obstet Gynecol 1986;155:135-9. DOI
  3. Lieberman HR, Corkin S, Spring BJ. The effects of dietary neurotransmitter precursors on human behavior. Am J Clin Nutr 1985;42:366-70. PubMed
  4. U. S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, Office of Nutritional Products, Labeling, and Dietary Supplements. Information Paper on L-Tryptophan and 5-hydroxy-L-tryptophan, February 2001.
  5. Sullivan EA, Kamb ML, Jones JL, et al. The natural history of eosinophilia-myalgia syndrome in a tryptophan-exposed cohort in South Carolina. Arch Intern Med 1996;156:973-9. DOI
  6. Philen RM, Hill RH, Flanders WD, et al. Tryptophan contaminants associated with eosinophilia-myalgia syndrome. Am J Epidemiol 1993;138:154-9. PubMed
  7. Bohme A, Wolter M, Hoelzer D. L-tryptophan-related eosinophilia-myalgia syndrome possibly associated with a chronic B-lymphocytic leukemia. Ann Hematol 1998;77:235-8. PubMed
  8. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  9. Priori R, Conti F, Luan FL, et al. Chronic fatigue: a peculiar evolution of eosinophilia myalgia syndrome following treatment with L-tryptophan in four Italian adolescents. Eur J Pediatr 1994;153:344-6..
  10. Klein R, Berg PA. A comparative study on antibodies to nucleoli and 5-hydroxytryptamine in patients with fibromyalgia syndrome and tryptophan-induced eosinophilia-myalgia syndrome. Clin Investig 1994;72:541-9.. PubMed
  11. Simat TJ, Kleeberg KK, Muller B, Sierts A. Synthesis, formation, and occurrence of contaminants in biotechnologically manufactured L-tryptophan. Adv Exp Med Biol 1999;467:469-80.. PubMed
  12. Shaw K, Turner J, Del Mar C. Tryptophan and 5-hydroxytryptophan for depression. Cochrane Database Syst Rev 2002;(1):CD003198. PubMed
  13. Kilbourne EM, Philen RM, Kamb ML, Falk H. Tryptophan produced by Showa Denko and epidemic eosinophilia-myalgia syndrome. J Rheumatol Suppl 1996;46:81-8.
  14. Horwitz RI, Daniels SR. Bias or biology: evaluating the epidemiologic studies of L-tryptophan and the eosinophilia-myalgia syndrome. J Rheumatol Suppl 1996;46:60-72.
  15. Shapiro S. Epidemiologic studies of the association of L-tryptophan with the eosinophilia-myalgia syndrome: a critique. J Rheumatol Suppl 1996;46:44-58.
  16. Mayeno AN, Gleich GJ. The eosinophilia-myalgia syndrome: lessons from Germany. Mayo Clin Proc 1994;69:702-4. PubMed
  17. Carr L, Ruther E, Berg PA, Lehnert H. Eosinophilia-myalgia syndrome in Germany: an epidemiologic review. Mayo Clin Proc 1994;69:620-5. PubMed
  18. Ullrich SS, Fitzgerald PCE, Giesbertz P, Steinert RE, Horowitz M, Feinle-Bisset C. Effects of intragastric administration of tryptophan on the blood glucose response to a nutrient drink and energy intake, in lean and obese men. Nutrients 2018;10(4). pii: PubMed

See these in context on the L-tryptophan monograph →

Parts of this content are provided by the Therapeutic Research Center, LLC.

DISCLAIMER: Currently this does not check for drug-drug interactions. This is not an all-inclusive comprehensive list of potential interactions and is for informational purposes only. Not all interactions are known or well-reported in the scientific literature, and new interactions are continually being reported. Input is needed from a qualified healthcare provider including a pharmacist before starting any therapy. Application of clinical judgment is necessary.

© 2021 Therapeutic Research Center, LLC

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