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Dietary supplement

L-Tryptophan Ingredients & Drug Interactions

by Lidtke

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

L-Tryptophan is a dietary supplement by Lidtke 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 Lidtke

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 make serotonin, a chemical messenger involved in mood and sleep. The powder form allows flexible dosing.

There are no other inactive ingredients listed.

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: support healthy sleep and mood.
  • We looked for evidence on: Anxiety, Depression, Premenstrual dysphoric disorder (PMDD), Premenstrual syndrome (PMS), Seasonal affective disorder (SAD), Insomnia — and 3 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 mixed. For depression, the data rates it as possibly ineffective.

For anxiety, athletic performance, teeth grinding (bruxism), and premenstrual dysphoric disorder, there isn't enough reliable evidence to know whether it works. If you're considering this product for a specific health concern, talk with your doctor about whether the evidence supports its use for your situation.

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 by mouth, though it can cause belching, diarrhea, drowsiness, dry mouth, flatulence, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, and vomiting. The product comes with a cautionary note about past contamination issues: in 1989, a batch of L-tryptophan from a Japanese manufacturer was linked to more than 1,500 cases of a serious neurological condition called eosinophilia-myalgia syndrome (EMS).

Most modern products are considered safe from that specific source, but it's something to be aware of. The safety data advises against L-tryptophan during pregnancy and while breastfeeding.

If you are pregnant, planning pregnancy, or breastfeeding, talk with your doctor or pharmacist before starting this product.

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 L-Tryptophan, double-check with your doctor or pharmacist if you take CNS depressants (sedatives, sleep aids, opioids, or some pain relievers)—risk of increased drowsiness is Major. Also confirm if you're on serotonergic drugs like antidepressants or certain migraine or pain medications—risk is Moderate and includes possible serotonin syndrome.

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 be worth considering if you're exploring options for mood or sleep and your doctor agrees the evidence fits your situation—but it's not a proven treatment for depression or anxiety. The main caution is mixing it with sedatives or serotonin-based medications; if you take either category, check with your doctor or pharmacist before starting.

Pregnancy and breastfeeding are not ideal times for this supplement based on current safety data.

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 Mar 24, 2020.

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 Lidtke
Barcode (UPC) 630610003759
Net contents 250 Gram(s) Powder
Market status On market
Date entered into DSLD Mar 24, 2020
DSLD ID 215289
Product type Amino Acid/protein
Supplement form Powder
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 Lidtke, 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:
0.33 tsp
Maximum serving Sizes:
0.33 tsp
Servings per container
500
UPC/BARCODE
630610003759
IngredientAmount% DV
L-Tryptophan500 mg--

Other ingredients: None

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.
General Statements

Thank you for choosing L-Tryptophan by Lidtke. We sincerely wish the best of health for you and your family.

Purest on the planet Superb quality since 1994

As certified by the manufacturer.

Formulation

L-Tryptophan is a natural building block of serotonin, the neurotransmitter that plays an important role in appetite, mood, normal sleep patterns, and nervous-system health. When your body needs extra help producing serotonin for peaceful sleep and a more relaxed outlook, choose Lidtke L-Tryptophan. Lidtke stands behind each product and guarantees customer satisfaction for 365 days from the date of purchase.

Sleep well, stay calm Supports healthy sleep & mood

No added gluten, yeast, wheat, corn, soy, dairy, eggs, tree nuts, peanuts, fish, shellfish, salt, sugar, artificial color or flavor, or preservatives. Non-GMO.

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.

Precautions

Warning: Keep out of reach of children.

If you are pregnant, lactating, taking any medications (especially MAOIs, Tricyclics, or SSRIs), or have a medical condition, consult your doctor.

Discontinue use if adverse reaction occurs. Do not use if seal is damaged or missing.

Adverse events may be reported above.

Storage

Keep lid tightly closed. Keep in a cool, dry place.

Formula

L-Trytophan, USP

Seals/Symbols

GMP

FDA Statement of Identity

A Dietary Supplement

Suggested/Recommended/Usage/Directions

Directions (Adults): Take 1/3 level teaspoon or as directed by a health-care professional. Best if taken at bedtime or between meals.

See for yourself

L-Tryptophan by Lidtke label

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

What’s inside

The Ingredients in L-Tryptophan by Lidtke

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

Serving size0.33 tsp Dosage formPowder Servings per container500 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: None. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Tryptophan by Lidtke 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.

Lidtke

See all Lidtke products
Name
Lidtke Technologies
City
Casa Grande
State
AZ
ZipCode
85122
Phone Number
1-800-404-8185
Pharmacist Counseling Corner

L-Tryptophan by Lidtke: Common Questions

Does L-Tryptophan by Lidtke 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.
Can I take L-Tryptophan if I'm on an antidepressant?
Not without checking first. L-Tryptophan and antidepressants both work through serotonin, and combining them could raise the risk of serotonin-related side effects, including a serious condition called serotonin syndrome. Talk with your doctor or pharmacist about your specific antidepressant before starting L-Tryptophan.
Will L-Tryptophan help my depression?
The evidence rates L-Tryptophan as possibly ineffective for depression, meaning it's not shown to be a reliable treatment for that condition. If you're looking for depression support, discuss proven options with your doctor.
What are the common side effects?
Most people tolerate L-Tryptophan well, but you might notice belching, diarrhea, drowsiness, dry mouth, gas, headache, heartburn, lightheadedness, nausea, stomach pain, blurred vision, or vomiting. Start with a low dose to see how you respond.
Is L-Tryptophan safe if I'm pregnant or breastfeeding?
The safety data advises against L-Tryptophan during pregnancy and while breastfeeding. If you are or plan to become pregnant, or if you're nursing, talk with your doctor or pharmacist before taking this product.
Should I be concerned about the eosinophilia-myalgia syndrome cases I've heard about?
In 1989, a contaminated batch from one Japanese manufacturer caused over 1,500 cases of that serious neurological condition. Most modern L-Tryptophan products are produced under different standards, but it's something to discuss with your pharmacist if you have concerns about source and purity.

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

Not sure if L-Tryptophan 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 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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