Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

L-Tryptophan Peptide Ingredients & Drug Interactions

by Jarrow Formulas

Tablet Or Pill Category: Amino Acid/protein
Most serious interaction: Major
The interaction bottom line Most serious interaction: Major

L-Tryptophan Peptide 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 Peptides. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of L-Tryptophan Peptide 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.
  • “L-Tryptophan Peptides” is listed as a grouped ingredient — the label gives one combined amount (1,350 mg) without saying how much of each component you get.

This product contains a single active ingredient: L-tryptophan peptides, which are chains of the amino acid L-tryptophan. L-tryptophan is an essential amino acid your body uses to make serotonin, a chemical messenger involved in mood, sleep, and other functions.

The product also contains several inactive ingredients — calcium phosphate, cellulose, stearic acid, silicon dioxide, magnesium stearate, and a food-grade coating — which serve as fillers and binders to form the tablet.

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: relaxation, restful sleep and positive mood.
  • We looked for evidence on: Anxiety, Depression, Premenstrual syndrome (PMS), Premenstrual dysphoric disorder (PMDD), Seasonal affective disorder (SAD), insomnia — and 1 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).

The evidence on L-tryptophan for the conditions it's marketed for is limited. For depression, the data we hold rates it as possibly ineffective.

For anxiety, athletic performance, teeth grinding (bruxism), and premenstrual dysphoric disorder (PMDD), there isn't enough reliable evidence to establish whether it works. If you're considering this product for any of these uses, talk it over with your doctor — they can help you weigh the limited evidence against other options.

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, flatulence, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, and vomiting.

A serious rare concern is eosinophilia-myalgia syndrome (EMS), a neurological disorder — however, nearly all cases documented in the U.S. in the late 1980s were traced to a contaminated batch from a single Japanese manufacturer, and modern products are produced under stricter controls. The safety data advises against L-tryptophan during pregnancy and while 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, alcohol, or other drugs that cause drowsiness — because L-tryptophan may boost their sedative effect. Also double-check if you're on serotonergic medications like antidepressants or migraine drugs, as combining them with L-tryptophan might increase serotonin-related side effects.

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 Peptide is an option if you're exploring amino acid support for mood or sleep, but the evidence for depression is weak and evidence for other uses is lacking. The biggest concern is mixing it with sedating drugs or serotonin-based medications — if you take any of those, check first with your doctor or pharmacist before adding this.

Avoid it if you're pregnant or breastfeeding.

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 Dec 22, 2019.

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 Peptide, straight from the product label.

Brand Jarrow Formulas
Barcode (UPC) 790011150671
Net contents 60 Tablet(s)
Market status On market
Date entered into DSLD Dec 22, 2019
DSLD ID 212250
Product type Amino Acid/protein
Supplement form Tablet Or Pill
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegetarian, Adult (18 - 50 Years), Gluten 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 Peptide 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:
2 Tablet(s)
Maximum serving Sizes:
2 Tablet(s)
Servings per container
30
UPC/BARCODE
790011150671
IngredientAmount% DV
L-Tryptophan Peptides1350 mg--
L-Tryptophan500 mg--

Other ingredients: Calcium Phosphate, Cellulose, Stearic Acid, Silicon Dioxide, Magnesium Stearate, food-grade Coating

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

Usage: Take 2 tablets on an empty stomach 30 minutes before sleep with water or fruit juice or as directed by your qualified healthcare professional.

Precautions

Warning: Do not drive or operate machinery immediately following use of this product; Do not take this product if you are on any medications (especially antidepressents [e.g., SSRIs (selective serotonin reuptake inhibitors)]).

Warning: Do not drive or operate machinery immediately following use of this product; Do not take this product if you are on any medications (especially antidepressents [e.g., SSRIs (selective serotonin reuptake inhibitors)]). If you are pregnant breastfeeding, trying to conceive, under the age of 18, or have a medical condition, consult your qualified healthcare professional before using this product.

If you are pregnant breastfeeding, trying to conceive, under the age of 18, or have a medical condition, consult your qualified healthcare professional before using this product.

Keep out of the reach of children.

Contains: Milk.

No wheat, gluten, soybeans, egg, fish/shellfish, or peanuts/tree nuts.

Formulation

Jarrow Formulas L-Tryptophan Peptide uses PepForm technology.

For relaxation, positive mood & sleep

Veggie

No wheat, gluten, soybeans, egg, fish/shellfish, or peanuts/tree nuts.

Suitable for vegetarians.

Formula

L-tryptophan is an essential amino acid and must be obtained from food or supplements. L-tryptophan is metabolized to serotonin (5-hydroxytryptamine) and melatonin, which is important for relaxation, restful sleep and positive mood.

TRP PepForm Tryptophan Peptides

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.

FDA Statement of Identity

Dietary Supplement

Brand IP Statement(s)

PepForm is a trademark of Glanbia plc.

2018 Jarrow Formulas

See for yourself

L-Tryptophan Peptide 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 Peptide by Jarrow Formulas

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

Serving size2 Tablet(s) Dosage formTablet Or Pill Servings per container30 Amounts shown are per serving.

L-Tryptophan Peptides

Interacts with
394 drugs
1350 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 Peptides monograph & interactions

Other (inactive) ingredients: Calcium Phosphate, Cellulose, Stearic Acid, Silicon Dioxide, Magnesium Stearate, Food-grade Coating. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Tryptophan Peptide by Jarrow Formulas Drug Interactions

Want to check YOUR meds against L-Tryptophan Peptide?

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 Peptide 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-Tryptophan Peptides2 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 Peptide, from the product label.

Jarrow Formulas

See all Jarrow Formulas products
Name
Jarrow Formulas Superior Nutrition and Formulation
Street Address
P.O. Box 35994
City
Los Angeles
State
CA
ZipCode
90035-4317
Web Address
www.Jarrow.com
Pharmacist Counseling Corner

L-Tryptophan Peptide by Jarrow Formulas: Common Questions

Does L-Tryptophan Peptide by Jarrow Formulas interact with any medications?
Yes. Based on its ingredients, L-Tryptophan Peptide 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 Peptide 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.
What are L-tryptophan peptides, and why are they in this product?
L-tryptophan peptides are chains of the amino acid L-tryptophan. Your body uses L-tryptophan to make serotonin, a chemical that influences mood, sleep, and other functions. The product delivers L-tryptophan in peptide form as a potential dietary support.
Does this really help with depression or anxiety?
The evidence is weak. For depression, the data rates L-tryptophan as possibly ineffective. For anxiety, there isn't enough reliable evidence to say whether it works. Talk with your doctor about whether this is right for you.
What are the most common side effects?
Most often, users report belching, diarrhea, drowsiness, dry mouth, gas, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, or vomiting. Most people tolerate it fairly well, but side effects vary.
I've heard about a contamination scare with L-tryptophan. Should I be worried?
In 1989, a contaminated batch from one Japanese manufacturer caused a neurological disorder called eosinophilia-myalgia syndrome (EMS) in over 1,500 people in the U.S. About 95% of those cases were tied to that one manufacturer. Modern products are made under stricter controls, though the concern remains documented in the safety data.
Can I take this while pregnant or breastfeeding?
The safety data advises against L-tryptophan during pregnancy and while breastfeeding. If you're pregnant or nursing and interested in this product, talk with your doctor or pharmacist for personalized guidance.
Can I take this with my sleep medication or antidepressant?
Not without checking first. L-tryptophan can add to the drowsiness of sleep aids or sedating drugs, and it may increase serotonin-related side effects when combined with antidepressants. Ask your doctor or pharmacist before combining them.

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

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

Our pharmacists answer your medication & supplement questions — free.

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 Peptide label
Sources

Sources & How We Checked

L-Tryptophan Peptide'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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