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Dietary supplement

L-Tryptophan Ingredients & Drug Interactions

by SuperiorLabs

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

L-Tryptophan is a dietary supplement by SuperiorLabs 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 by SuperiorLabs

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 product contains one active ingredient: L-tryptophan, an amino acid your body uses to produce serotonin, a chemical messenger that helps regulate mood, sleep, and other functions. The capsules also contain rice and cellulose as inactive ingredients.

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: amino acid that supports sleep and brain function.
  • We looked for evidence on: Anxiety, Depression, Premenstrual dysphoric disorder (PMDD), Premenstrual syndrome (PMS), Seasonal affective disorder (SAD), Sleep disorders — and 2 related terms.
  • The closest evidence on file: L-tryptophan is rated "Possibly Ineffective" for Depression (Natural Medicines).
  • Also on file: L-tryptophan is rated "Insufficient Reliable Evidence To Rate" for Anxiety, Premenstrual dysphoric disorder (PMDD), Premenstrual syndrome (PMS), Seasonal affective disorder (SAD).

L-tryptophan has been studied for depression, but the evidence rates it as possibly ineffective for that use. For anxiety, athletic performance, teeth grinding (bruxism), and premenstrual dysphoric disorder, there isn't enough reliable evidence yet to say whether it works.

The data we hold doesn't establish an effectiveness rating for these other purposes.

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 when taken by mouth. Common side effects include belching, diarrhea, drowsiness, dry mouth, gas, headache, lightheadedness, nausea, stomach pain, blurred vision, and vomiting.

In rare cases, it's been linked to a serious neurological condition called eosinophilia-myalgia syndrome (EMS), though almost all documented cases in the U.S. came from contaminated product made by a single Japanese manufacturer in 1989. The product carries a history of that contamination scare, so caution is warranted.

During pregnancy, there isn't enough safety data, so the guidance advises against use. The same applies to breastfeeding — safety hasn't been established, so it's best avoided then too.

Talk with your doctor or pharmacist before using this if you're pregnant, planning pregnancy, or nursing.

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.

Check with your pharmacist before using L-Tryptophan if you take CNS depressants (sedatives, sleep aids, anxiety medications, opioids, or drink alcohol) — the risk is Major. Also check if you're on serotonergic drugs like antidepressants (SSRIs, SNRIs), certain pain or migraine medications — the risk is Moderate.

Use the medication checker on this page to be sure.

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 someone looking for a natural mood or sleep support, but it has real interactions with common medications and side effects to watch for. If you take anything for depression, anxiety, pain, or sleep, you need to check with us first.

Pregnant or breastfeeding? Skip it.

Anyone considering this should talk to their pharmacist about their full medication list.

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 Sep 25, 2025.

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, straight from the product label.

Brand SuperiorLabs
Barcode (UPC) 850569006209
Net contents 120 Vegetable Capsule(s)
Market status On market
Date entered into DSLD Sep 25, 2025
DSLD ID 338186
Product type Amino Acid/protein
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
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 by SuperiorLabs, 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
120
UPC/BARCODE
850569006209
IngredientAmount% DV
L-Tryptophan500 mg--

Other ingredients: Rice, Cellulose

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.
Formula

L-Tryptophan is an amino acid that is converted in the body to serotonin, an important neurotransmitter that supports many functions in the brain and is used to aid sleep. As we age, many find it more difficult to get a good night's rest and L-Tryptophan can help maintain serotonin levels to support normal sleep.

Amino acid

Suggested/Recommended/Usage/Directions

Suggested use: As a dietary supplement, adult take 1 capsule two to three times daily, or as directed by your health care practitioner. Best when taken with a meal.

Precautions

Caution: Do not exceed recommended dosage. Do not use if safety seal is damaged or missing.

Please consult a physician before consuming this product if you are pregnant or nursing, taking medication or have a medical condition.

Not intended for use by individuals under the age of 18. Keep out of reach of children.

Storage

Store in a cool, dry place.

Seals/Symbols

Metal Safe Heavy Metal Tested GMP Compliant Facility Manufactured in the USA with globally sourced ingredients

Formulation

Metal Safe Heavy Metal Tested

Optimal absorption Premium potency Promotes restful sleep Promotes relaxation Maintains serotonin levels This product is formulated, developed and manufactured in a Food and Drug Administration-registered and GMP-compliant facility, 3rd party inspected by a leading compliance authority for superior quality assurance.

Does not contain: magnesium stearate, dioxides, preservatives, or artificial ingredients of any kind.

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.

FDA Statement of Identity

Dietary Supplement

See for yourself

L-Tryptophan by SuperiorLabs label

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

What’s inside

The Ingredients in L-Tryptophan by SuperiorLabs

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 container120 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: Rice, Cellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Tryptophan by SuperiorLabs Drug Interactions

Want to check YOUR meds against L-Tryptophan?

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 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, from the product label.

SuperiorLabs

See all SuperiorLabs products
Name
Superior Labs, LLC.
City
Park City
State
UT
ZipCode
84098
Phone Number
(888) 708-5227
Web Address
www.superiorlabs.com
Pharmacist Counseling Corner

L-Tryptophan by SuperiorLabs: Common Questions

Does L-Tryptophan by SuperiorLabs interact with any medications?
Yes. Based on its ingredients, L-Tryptophan 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 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.
Will L-tryptophan make me drowsy?
Yes, clinical research shows L-tryptophan can cause fatigue and drowsiness. If you drive or operate machinery, be aware of this effect, especially when you first start taking it or if you combine it with other drugs that make you sleepy.
Is this safe to take if I'm pregnant or breastfeeding?
No. There isn't enough safety data during pregnancy, so it's advised against then. The same goes for breastfeeding — safety hasn't been established. Talk with your doctor or pharmacist about alternatives if you're pregnant, planning to become pregnant, or nursing.
What's eosinophilia-myalgia syndrome, and should I worry about it?
EMS is a rare neurological disorder that was linked to L-tryptophan use in the late 1980s. Nearly all U.S. cases came from contaminated product made by one Japanese manufacturer. Because of that scare, the FDA limited L-tryptophan imports. Modern products are safer, but the history means caution is still warranted.
Can I take this with my antidepressant?
Not without checking first. L-tryptophan combines with antidepressants to potentially increase serotonin levels too much, raising the risk of serotonin syndrome and other serious effects. Use the medication checker here or call your pharmacist before starting.
What are the most common side effects?
Belching, diarrhea, drowsiness, dry mouth, gas, headache, lightheadedness, nausea, stomach pain, blurred vision, and vomiting have all been reported. Most people tolerate it okay, but these effects are worth knowing about before you start.

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

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

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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 label
Sources

Sources & How We Checked

L-Tryptophan'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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