Interactions on record — worth a quick check against your medications. Check your meds →
Dietary supplement

Zen Sleep with P5P and 5-HTP Ingredients & Drug Interactions

by Allergy Research Group

Zen Sleep with P5P and 5-HTP label
See full label image
Capsule Category: Other Combinations
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 30, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Zen Sleep with P5P and 5-HTP against your medications. The heart of this page is the interaction checker and the full interaction report — how this product’s ingredients may interact with prescription and over-the-counter medicines you may be taking.

Around that, we add a pharmacist’s high-level view of the product as a whole — what’s inside, the evidence for its stated use, how transparent the label is, and what safety data exists — so you can see the full picture in one place. It’s educational information from our licensed clinical databases and the clinical staff at HelloPharmacist — not medical advice — and we don’t sell or endorse products. Our editorial policy

The interaction bottom line Most serious interaction: Moderate

Zen Sleep with P5P and 5-HTP is a dietary supplement by Allergy Research Group with 4 active ingredients. Its ingredients are commonly taken for low mood or depression, anxiety and stress, sleep problems.Based on those ingredients, 572 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Suntheanine, GABA, L-5-Hydroxytryptophan. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

Jump to a section

Check Your Meds Against Zen Sleep with P5P and 5-HTP by Allergy Research Group

Ask about any prescription or over-the-counter medication and we check it for interactions with Zen Sleep with P5P and 5-HTP by Allergy Research Group — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of Zen Sleep with P5P and 5-HTP by Allergy Research Group

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

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Oct 1, 2026

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 4 of its 4 active ingredients.
  • No proprietary blends here — you can verify the dose of every single component.

Zen Sleep contains four active ingredients. L-5-hydroxytryptophan (5-HTP) is an amino acid your body uses to make serotonin, a chemical messenger involved in mood and sleep.

Vitamin B6 (also called pyridoxine) is an essential nutrient your body needs for nerve function, immune health, and metabolism. Suntheanine is a form of theanine, a compound found in green tea that promotes relaxation without sedation.

GABA (gamma-aminobutyric acid) is a naturally occurring brain chemical that supports calm and relaxation. The capsule also contains inactive ingredients—hydroxypropyl methylcellulose, microcrystalline cellulose, rice hull concentrate, gum Arabic, and sunflower oil—which serve as binders and capsule material.

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.

Why this rating?
  • The label markets this product for: promote relaxation and support normal healthy sleep.
  • We looked for evidence on: Insomnia, Anxiety, Generalized anxiety disorder (GAD), sleep quality, sleep onset, sleep maintenance.
  • The closest evidence on file: Gamma-aminobutyric Acid (gaba) is rated "Insufficient Reliable Evidence To Rate" for Anxiety (Natural Medicines).
  • Also on file: Gamma-aminobutyric Acid (gaba) is rated "Insufficient Reliable Evidence To Rate" for Insomnia.
  • Also on file: 5-htp is rated "Insufficient Reliable Evidence To Rate" for Anxiety, Insomnia.

The evidence for this product's ingredients is mixed. 5-HTP is possibly effective for depression, though it hasn't been reliably studied for panic disorder, cerebellar ataxia, or Alzheimer's disease.

Vitamin B6 is effective for sideroblastic anemia and vitamin B6 deficiency, and likely effective for high homocysteine; it's possibly effective for pregnancy-related nausea. Theanine is possibly effective for cognitive function but lacks reliable evidence for anxiety, cognitive decline, Alzheimer's, or OCD.

GABA's effectiveness for anxiety, ADHD, athletic performance, and other conditions lacks sufficient evidence in the data we hold. Overall, while 5-HTP shows some promise for depression, the product as a whole has not been studied as a sleep aid formulation.

The evidence, ingredient by ingredient 5-htp Vitamin B6 Theanine Gamma-aminobutyric Acid (gaba)

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 4 of the 4 matched ingredients.
  • Pregnancy & breastfeeding safety ratings cover 4 of 4.
  • General safety write-ups exist for 4 of 4.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

5-HTP is generally well tolerated short-term, but the facts show it carries real risks: it commonly causes nausea, diarrhea, drowsiness, headache, and abdominal pain—effects that are dose-dependent. Rare but serious side effects include hallucinations, mania, and aggression, especially at high doses or when combined with carbidopa.

Vitamin B6 is safe at normal dietary levels and standard supplement doses, but the facts warn that high doses over time can damage nerves (sensory neuropathy), with increased risk above 1,000 mg daily. Theanine is generally well tolerated for short-term use in healthy adults, though long-term safety isn't established; headaches and drowsiness have been reported.

GABA appears well tolerated orally short-term, with drowsiness, nausea, and muscle weakness reported occasionally, but long-term safety data is lacking.

Side effects, ingredient by ingredient 5-htp Vitamin B6 Theanine Gamma-aminobutyric Acid (gaba)

Meds to double-check

Moderate interaction found
Known Interaction Concern · database check
Moderate identified

The most serious documented interaction for these ingredients is Moderate. Check your medications for a personalized result.

Why this rating?
  • 4 of the 4 matched ingredients can interact with medications — Gamma-aminobutyric Acid (gaba), 5-htp, Vitamin B6, Theanine.
  • The most serious interaction on file is rated Moderate.
  • Some involve high-stakes drug classes: Parkinson's medications.
  • For scale: 572 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 before taking this if you use any serotonergic drugs (antidepressants, certain pain relievers, migraine medications), sedating medications (sleep aids, antihistamines, opioids), blood pressure medications, seizure medications (phenobarbital or phenytoin), the heart medication amiodarone, or carbidopa for Parkinson's disease. These are the main medication types where documented interactions exist.

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. Moderate medication interactions have been identified, and safety information is well characterized.

If you're looking to support sleep and calm with natural ingredients, this product has a mixed evidence base—5-HTP shows some promise for mood, but the sleep-supporting effect of the combination hasn't been established. Be aware that 5-HTP carries real risks if you take serotonergic medications (like many antidepressants), blood pressure drugs, seizure medications, or sedating medications, and that high-dose vitamin B6 can damage nerves over time.

Before you start, talk with your doctor or pharmacist about whether this product is right for you and your medications.

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

Assessment coverage: 4 of 4 active ingredients 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 Zen Sleep with P5P and 5-HTP, straight from the product label.

Brand Allergy Research Group
Barcode (UPC) 713947773608
Net contents 60 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Jan 24, 2024
DSLD ID 304290
Product type Other Combinations
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Women (not pregnant or lactating)
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 Zen Sleep with P5P and 5-HTP by Allergy Research Group, 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 Capsule(s)
Maximum serving Sizes:
2 Capsule(s)
Servings per container
30
UPC/BARCODE
713947773608
IngredientAmount% DV
L-5-Hydroxytryptophan100 mg--
Vitamin B610 mg588%
Suntheanine200 mg--
GABA550 mg--

Other ingredients: Hydroxypropyl Methylcellulose, Microcrystalline Cellulose, Rice Hull Concentrate, Gum Arabic, Sunflower Oil

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

Zen Sleep includes the same amounts of GABA and L-Theanine as the best-selling 200 mg of Zen, augmented with Vitamin B6 as P5P, and 5-HTP, the precursor to serotonin and melatonin.

Formulation

This combination helps promote a relaxed state, and provides the necessary factors for the body to produce melatonin, supporting normal, healthy sleep.

Hypoallergenic

Suggested/Recommended/Usage/Directions

Suggested use As a dietary supplement, 2 capsules 30 minutes before bedtime, or as directed by a healthcare practitioner.

Precautions

Warning: Not indicated for pregnant or nursing women. If taking antidepressants or other psychotropic medications, use only under the supervision of a qualified healthcare practitioner.

Storage

Keep in a cool, dry place, tightly capped.

FDA Disclaimer Statement

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

Brand IP Statement(s)

Suntheanine Suntheanine is a registered trademark of Taiyo International, Inc.

FDA Statement of Identity

Dietary Supplement

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

Zen Sleep with P5P and 5-HTP by Allergy Research Group label

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

Zen Sleep with P5P and 5-HTP label

Label images are published by the NIH Dietary Supplement Label Database for the version of this product on file. Always read your actual product label.

View the full label (PDF)
What’s inside

The Ingredients in Zen Sleep with P5P and 5-HTP by Allergy Research Group

These are the 4 active ingredients this product is made of. Select any to open its full monograph.

Serving size2 Capsule(s) Dosage formCapsule Servings per container30 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

L-5-Hydroxytryptophan

Interacts with
398 drugs
100 mg per serving

5-HTP is a compound your body uses to make serotonin, and people take it as a supplement hoping to improve mood, sleep, and headaches. Some early rese...

L-5-Hydroxytryptophan monograph & interactions

Vitamin B6

Interacts with
210 drugs
10 mg per serving Form: Pyridoxal 5-Phosphate

Vitamin B6 (pyridoxine) is an essential water-soluble vitamin that your body needs for metabolism, brain function, and making red blood cells. It is b...

Vitamin B6 monograph & interactions

Suntheanine

Interacts with
565 drugs
200 mg per serving Form: L-Theanine

Theanine (usually L-theanine) is an amino acid found naturally in tea leaves that many people take to feel calmer and less stressed without strong dro...

Suntheanine monograph & interactions

GABA

Interacts with
419 drugs
550 mg per serving

GABA is a calming chemical messenger (neurotransmitter) that your body makes on its own, and it is sold as a supplement for stress, anxiety, and sleep...

GABA monograph & interactions

Other (inactive) ingredients: Hydroxypropyl Methylcellulose, Microcrystalline Cellulose, Rice Hull Concentrate, Gum Arabic, Sunflower Oil. These complete the product’s ingredient list but are not active constituents.

Interaction report

Zen Sleep with P5P and 5-HTP by Allergy Research Group Drug Interactions

Want to check YOUR meds against Zen Sleep with P5P and 5-HTP?

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
572Drugs
570 Moderate 2 Minor

Ingredients driving the most interactions

Suntheanine 565
GABA 419
L-5-Hydroxytryptophan 398
Vitamin B6 210

Individual Drug Interactions

The ingredients in Zen Sleep with P5P and 5-HTP interact with 572 drugs. Click any drug to see the details.

4 of the 4 ingredients in Zen Sleep with P5P and 5-HTP interact with drugs. Each result below shows which ingredient is responsible. Suntheanine GABA L-5-Hydroxytryptophan Vitamin B6

Each ingredient & the kinds of drugs it affects

For each ingredient in Zen Sleep with P5P and 5-HTP with known interactions, here are the types of medications they can affect. Open any type for the detail — or search your exact drug in the checker above.

Suntheanine3 drug types · 565 drugs

Antihypertensive Drugs

Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Animal research shows that theanine can lower blood pressure in spontaneously hypertensive animals. Theoretically, concomitant use of theanine and antihypertensive drugs might potentiate the antihypertensive activity.

Likelihood Possible Evidence D
Cns Depressants

Theoretically, theanine might have additive sedative effects when used in conjunction with CNS depressants. However, it is unclear if this concern is clinically relevant.
Theoretically, theanine may compete with glutamate and/or increase plasma gamma-aminobutyric acid (GABA) levels, which could cause CNS depression. In one clinical study, some subjects taking oral theanine reported drowsiness.

Likelihood Unlikely Evidence D
Serotonergic Drugs

Clinical studies regarding the effects of L-theanine on serotonin levels are conflicting. Some studies suggest it can increase serotonin levels in the brain while others report that it may decrease them. Nevertheless, there have been no reports of l-theanine being a causative agent in serotonergic-related side effects or serotonin syndrome.

Likelihood Unlikely Evidence C
Suntheanine full monograph & interactions

GABA2 drug types · 419 drugs

Antihypertensive Drugs

Theoretically, taking GABA with antihypertensive drugs might increase the risk of hypotension.
Some clinical research shows that GABA can decrease blood pressure in patients with hypertension.

Likelihood Possible Evidence B
Cns Depressants

Theoretically, GABA might have additive sedative effects when used in conjunction with CNS depressants. However, it is unclear if this concern is clinically relevant.
Endogenous GABA has well-established relaxant effects and GABA(A) receptors have an established physiological role in sleep. However, the effects of GABA supplements are unclear, as it is unknown whether exogenous GABA crosses the blood-brain barrier. Although there have been limited reports of drowsiness or tiredness with GABA supplements, these effects have not been widely reported in clinical studies. Additionally, intravenous GABA 0.1-1 mg/kg has been shown to induce anxiety in a dose-dependent manner.

Likelihood Unlikely Evidence D
GABA full monograph & interactions

L-5-Hydroxytryptophan3 drug types · 398 drugs

Carbidopa (Lodosyn)

Combining 5-HTP and carbidopa can increase the risk of serotonergic side effects.
Carbidopa is sometimes used with 5-HTP to minimize peripheral 5-HTP metabolism and boost the amount that reaches the brain. However, this combination might also increase the risk of some side effects including hypomania, restlessness, rapid speech, anxiety, insomnia, and aggressiveness. Combining carbidopa and 5-HTP might also increase the risk of scleroderma-like skin changes due to elevated serotonin levels.

Likelihood Possible Evidence D
Cns Depressants

Theoretically, concomitant use of 5-HTP with medications that cause sedation might have additive effects.
In clinical trials, 5-HTP has been associated with drowsiness and somnolence.

Likelihood Possible Evidence D
Serotonergic Drugs

Combining serotonergic drugs with 5-HTP might cause additive serotonergic effects.
5-HTP can increase serotonin levels and cause serotonergic effects. Theoretically, combining serotonergic drugs with 5-HTP might increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstrictive disorders. However, serotonin syndrome with 5-HTP has not yet been reported in humans. Monitor patients for signs of serotonin syndrome and other serotonergic side effects if using 5-HTP with serotonergic drugs.

Likelihood Possible Evidence D
L-5-Hydroxytryptophan full monograph & interactions

Vitamin B65 drug types · 210 drugs

Amiodarone (Cordarone)

Theoretically, vitamin B6 might increase the photosensitivity caused by amiodarone.
Despite initial case reports suggesting that pyridoxine may have a protective effect against amiodarone-induced photosensitivity, preliminary clinical research suggests that pyridoxine may actually exacerbate this adverse effect.

Likelihood Possible Evidence B
Antihypertensive Drugs

Theoretically, vitamin B6 may have additive effects when used with antihypertensive drugs.
Research in hypertensive rats shows that vitamin B6 can decrease systolic blood pressure. Similarly, clinical research in patients with hypertension shows that taking high doses of vitamin B6 may reduce systolic and diastolic blood pressure, possibly by reducing plasma levels of epinephrine and norepinephrine.

Likelihood Possible Evidence B
Phenobarbital (Luminal)

High doses of vitamin B6 may reduce the levels and clinical effects of phenobarbital.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenobarbital, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenobarbital to avoid high doses of vitamin B6.

Likelihood Possible Evidence D
Phenytoin (Dilantin)

High doses of vitamin B6 may reduce the levels and clinical effects of phenytoin.
Preliminary clinical evidence suggests that vitamin B6 200 mg daily can reduce plasma levels of phenytoin, possibly by increasing metabolism. It is not known whether lower doses have any effect. Advise people taking phenytoin to avoid high doses of vitamin B6.

Likelihood Possible Evidence D
Levodopa

Vitamin B6 may increase the metabolism of levodopa when taken alone, but not when taken in conjunction with carbidopa.
Vitamin B6 (pyridoxine) enhances the metabolism of levodopa, reducing its clinical effects. However, this interaction does not occur when carbidopa is used concurrently with levodopa (Sinemet). Therefore, it is not likely to be a problem in most people.

Likelihood Unlikely Evidence D
Vitamin B6 full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Zen Sleep with P5P and 5-HTP, from the product label.

Allergy Research Group

See all Allergy Research Group products
Name
Allergy Research Group
City
South Salt Lake
State
UT
ZipCode
84115
Phone Number
800.545.9960
Web Address
www.allergyresearchgroup.com
Pharmacist Counseling Corner

Zen Sleep with P5P and 5-HTP by Allergy Research Group: Common Questions

Does Zen Sleep with P5P and 5-HTP by Allergy Research Group interact with any medications?
Yes. Based on its ingredients, Zen Sleep with P5P and 5-HTP has a known interaction with 572 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Zen Sleep with P5P and 5-HTP contains 4 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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 this make me drowsy during the day?
Possibly. 5-HTP and theanine can both cause drowsiness, and that's actually part of the intended effect for sleep. But if you're sensitive, you might feel groggy the next day, especially when you first start. How much drowsiness you get depends on the dose and how your body responds.
Is it safe to take during pregnancy?
The facts show there isn't enough safety data for 5-HTP, theanine, or GABA during pregnancy, so it's best to avoid them unless your doctor advises otherwise. Vitamin B6 is rated Likely Safe at standard doses and Possibly Unsafe at high doses during pregnancy—talk with your doctor before taking this product if you're pregnant.
Can I take this if I'm breastfeeding?
The safety data for 5-HTP, theanine, and GABA while breastfeeding is insufficient, so it's best to avoid this product unless your doctor says it's okay. Vitamin B6 is rated Likely Safe while breastfeeding, but since the product contains other ingredients with unknown safety, check with your doctor or pharmacist first.
What are the most common side effects?
5-HTP commonly causes nausea, diarrhea, drowsiness, headache, and stomach pain—these are dose-dependent and may improve with continued use. Vitamin B6 and theanine can cause headaches. GABA may cause drowsiness, nausea, and mild throat burning. If side effects persist or worsen, stop and talk with your pharmacist.
How long does it take to work?
The facts don't specify how long before you'd notice sleep or mood benefits. Since 5-HTP and the other ingredients work on brain chemistry, it may take several days or longer. Your doctor or pharmacist can give you more personalized guidance on what to expect.
Is this safe to take long-term?
Long-term safety hasn't been well studied for theanine or GABA. 5-HTP has been used short-term with reasonable tolerance, but the facts don't confirm long-term safety. High doses of vitamin B6 over time can cause nerve damage. Talk with your doctor before taking this product for more than a few weeks.

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

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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.

Zen Sleep with P5P and 5-HTP label
Go deeper

The Full Monographs Behind Zen Sleep with P5P and 5-HTP’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

5-htp

Interacts with 398 drugs

5-HTP is a compound your body uses to make serotonin, and people take it as a supplement hoping to improve mood, sleep, and headaches. Some early research is promising, but the overall evide...

Read the full 5-htp monograph → Herb & supplement monograph

Vitamin B6

Interacts with 210 drugs

Vitamin B6 (pyridoxine) is an essential water-soluble vitamin that your body needs for metabolism, brain function, and making red blood cells. It is best known for helping with pregnancy-rel...

Read the full Vitamin B6 monograph → Herb & supplement monograph

Theanine

Interacts with 565 drugs

Theanine (usually L-theanine) is an amino acid found naturally in tea leaves that many people take to feel calmer and less stressed without strong drowsiness. Early research suggests it may...

Read the full Theanine monograph → Herb & supplement monograph

Gamma-aminobutyric Acid (gaba)

Interacts with 419 drugs

GABA is a calming chemical messenger (neurotransmitter) that your body makes on its own, and it is sold as a supplement for stress, anxiety, and sleep. The science behind oral GABA supplemen...

Read the full Gamma-aminobutyric Acid (gaba) monograph →
Sources

Sources & How We Checked

Zen Sleep with P5P and 5-HTP'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 82 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.

5-htp 32 references
  1. Birdsall TC. 5-Hydroxytryptophan: A Clinically-Effective Serotonin Precursor. Altern Med Rev 1998;3:271-80.
  2. Michelson D, Page SW, Casey R, et al. An eosinophilia-myalgia syndrome related disorder associated with exposure to L-5-hydroxytryptophan. J Rheumatol 1994;21:2261-5.
  3. Cangiano C, Ceci F, Cancino A, et al. Eating behavior and adherence to dietary prescriptions in obese adult subjects treated with 5-hydroxytryptophan. Am J Clin Nutr 1992;56:863-7. PubMed
  4. U.S. Food and Drug Administration. Impurities confirmed in dietary supplement 5-hydroxy-L-tryptophan. FDA Talk Paper, August 31, 1998; T98-48.
  5. Sternberg EM, Van Woert MH, Young SN, et al. Development of a scleroderma-like illness during therapy with L-5-hydroxytryptophan and carbidopa. N Engl J Med 1980;303:782-7. PubMed
  6. Poldinger W, Calanchini B, Schwarz W. A functional-dimensional approach to depression: serotonin deficiency as a target syndrome in a comparison of 5-hydroxytryptophan and fluvoxamine. Psychopathology 1991;24:53-81.
  7. Ribeiro CA. L-5-Hydroxytryptophan in the prophylaxis of chronic tension-type headache: a double-blind, randomized, placebo-controlled study. Headache 2000;40:451-6.
  8. 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.
  9. Singhal AB, Caviness VS, Begleiter AF, et al. Cerebral vasoconstriction and stroke after use of serotonergic drugs. Neurology 2002;58:130-3. PubMed
  10. Johnson KL, Klarskov K, Benson LM, et al. Presence of peak X and related compounds: the reported contaminant in case related 5-hydroxy-L-tryptophan associated with eosinophilia-myalgia syndrome. J Rheumatol 1999;26:2714-7.
  11. Takahashi S, Kondo H, Kato N. Effect of l-5-hydroxytryptophan on brain monoamine metabolism and evaluation of its clinical effect in depressed patients. J Psychiatr Res 1975;12:177-87. PubMed
  12. Iovieno, N., Dalton, E. D., Fava, M., and Mischoulon, D. Second-tier natural antidepressants: review and critique. J Affect.Disord. 2011;130(3):343-357. PubMed
  13. den Boer JA, Westenberg HG. Behavioral, neuroendocrine, and biochemical effects of 5-hydroxytryptophan administration in panic disorder. Psychiatry Res 1990;31:267-78. PubMed
  14. Jangid P, Malik P, Singh P, Sharma M, Gulia AK. Comparative study of efficacy of l-5-hydroxytryptophan and fluoxetine in patients presenting with first depressive episode. Asian J Psychiatr 2013;6:29-34. PubMed
  15. Ceci F, Cangiano C, Cairella M, et al. The effects of oral 5-hydroxytryptophan administration on feeding behavior in obese adult female subjects. J Neural Transm 1989;76:109-17. PubMed
  16. Angst J, Woggon B, Schoepf J. The treatment of depression with L-5-hydroxytryptophan versus imipramine. Results of two open and one double-blind study. Arch Psychiatr Nervenkr 1977;224:175-86. DOI
  17. Titus F, Dávalos A, Alom J, Codina A. 5-Hydroxytryptophan versus methysergide in the prophylaxis of migraine. Randomized clinical trial. Eur Neurol 1986;25:327-9. PubMed
  18. De Benedittis G, Massei R. Serotonin precursors in chronic primary headache. A double-blind cross-over study with L-5-hydroxytryptophan vs. placebo. J Neurosurg Sci 1985;29:239-48.
  19. Van Woert, M. H., Rosenbaum, D., Howieson, J., and Bowers, M. B., Jr. Long-term therapy of myoclonus and other neurologic disorders with L-5- hydroxytryptophan and carbidopa. N Engl J Med 1-13-1977;296(2):70-75. PubMed
  20. Wyatt, R. J., Vaughan, T., Galanter, M., Kaplan, J., and Green, R. Behavioral changes of chronic schizophrenic patients given L-5- hydroxytryptophan. Science 9-22-1972;177(54):1124-1126. PubMed
  21. Chase, T. N., Ng, L. K., and Watanabe, A. M. Parkinson's disease. Modification by 5-hydroxytryptophan. Neurology 1972;22(5):479-484.
  22. van Hiele LJ. l-5-Hydroxytryptophan in depression: the first substitution therapy in psychiatry? The treatment of 99 out-patients with 'therapy-resistant' depressions. Neuropsychobiology 1980;6:230-40. PubMed
  23. Pranzatelli, M. R., Tate, E., Huang, Y., Haas, R. H., Bodensteiner, J., Ashwal, S., and Franz, D. Neuropharmacology of progressive myoclonus epilepsy: response to 5- hydroxy-L-tryptophan. Epilepsia 1995;36(8):783-791. PubMed
  24. Trouillas P, Serratrice G, Laplane D, et al. Levorotatory form of 5-hydroxytryptophan in Friedreich's ataxia. Results of a double-blind drug-placebo cooperative study. Arch Neurol 1995;52:456-60. PubMed
  25. Bastard, J., Truelle, J. L., and Emile, J. [Effectiveness of 5 hydroxy-tryptophan in Parkinson's disease]. Nouv Presse Med 9-11-1976;5(29):1836-1837.
  26. Auffret, M., Comte, H., and Bene, J. Eosinophilia-myalgia syndrome induced by L-5 hydroxytryptophane: about three cases. Fund Clin Pharmacol 2013;Suppl 1(120):poster P2-204.
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Vitamin B6 32 references
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Theanine 6 references
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Gamma-aminobutyric Acid (gaba) 12 references
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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.

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