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Dietary supplement

Zen Theanine Ingredients & Drug Interactions

by AOR Advanced Orthomolecular Research Premium

Zen Theanine label
See full label image
Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Oct 7, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking Zen Theanine 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 Theanine is a dietary supplement by AOR Advanced Orthomolecular Research Premium with 1 active ingredient. Its ingredients are commonly taken for anxiety and stress, relaxation and calm, sleep support.Based on those ingredients, 565 medications have a known interaction with it, the most serious rated moderate. The ingredients most likely to interact are Suntheanine L-Theanine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

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Check Your Meds Against Zen Theanine by AOR Advanced Orthomolecular Research Premium

Ask about any prescription or over-the-counter medication and we check it for interactions with Zen Theanine by AOR Advanced Orthomolecular Research Premium — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of Zen Theanine by AOR Advanced Orthomolecular Research Premium

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 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

Zen Theanine is a single-ingredient supplement containing Suntheanine L-theanine, a naturally occurring amino acid found in green tea. The capsule itself is made from microcrystalline cellulose (a plant-based filler) and capsule material.

Does it work?

Moderate evidence
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
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: calm and relaxed alertness.
  • We looked for evidence on: Generalized anxiety disorder (GAD), Stress, Insomnia, Cognitive function, anxiety, relaxation — and 1 related terms.
  • The strongest evidence on file: Theanine is rated "Possibly Effective" for Cognitive function (Natural Medicines).
  • Also on file: Theanine is rated "Insufficient Reliable Evidence To Rate" for Generalized anxiety disorder (GAD), Insomnia, Stress.

The evidence for L-theanine is mixed. It's possibly effective for supporting cognitive function, but for age-related cognitive decline, Alzheimer disease, generalized anxiety, obsessive-compulsive disorder, and cancer, there isn't enough reliable evidence yet to say whether it works.

The data we hold doesn't establish a clear benefit for these other uses.

The evidence, ingredient by ingredient Theanine

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-theanine is generally well tolerated in healthy adults when used short-term, but we don't have solid long-term safety data. Common side effects include headaches, drowsiness, longer sleep duration, and more vivid dreams.

One case of facial tics in a child was reported, though the child had a history of tics and they stopped when theanine was discontinued, so a direct link wasn't clear. There isn't enough safety data in pregnancy or while breastfeeding — the facts advise avoiding supplements during both.

Talk with your doctor or pharmacist about whether it's right for you in these situations.

Side effects, ingredient by ingredient Theanine

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?
  • 1 of the 1 matched ingredient can interact with medications — Theanine.
  • The most serious interaction on file is rated Moderate.
  • For scale: 565 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 you start, double-check with your doctor or pharmacist if you take blood pressure medications (antihypertensives) — theanine might lower your pressure further. Also check if you're on central nervous system depressants (sedatives, sleep aids, opioids) or serotonergic drugs like antidepressants, even though the evidence of real-world problems is limited.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Moderate medication interactions have been identified, and safety information is well characterized.

Zen Theanine might appeal to someone looking to support focus or calm, though the evidence is strongest for cognitive function. If you're on blood pressure medication, sedating drugs, or antidepressants, you'll want to check with your doctor or pharmacist first — theanine can interact with these.

It's generally easy to tolerate short-term, but the long-term picture isn't clear yet.

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 Zen Theanine, straight from the product label.

Brand AOR Advanced Orthomolecular Research Premium
Barcode (UPC) 624917083415
Net contents 120 Vegetarian Capsule(s)
Market status On market
Date entered into DSLD Mar 24, 2020
DSLD ID 214728
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy Free
From the label
Everything in this section is reproduced from the manufacturer’s own product label — it’s the label speaking, not HelloPharmacist. We show it so you can see exactly what the maker states; we don’t verify or endorse those statements.

Supplement Facts

The label details for Zen Theanine by AOR Advanced Orthomolecular Research Premium, 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
624917083415
IngredientAmount% DV
Suntheanine L-Theanine225 mg--

Other ingredients: Microcrystalline Cellulose, Capsule

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.
Formulation

GMP Manufacturing Quality assured Independent testing

Promotes relaxation without drowsiness

Vegan

Non-GMO Gluten free

AOR guarantees that all ingredients have been declared on the label.

Made without wheat, gluten, corn, nuts, peanuts, soy, dairy, eggs, fish, shellfish or any animal byproduct.

Precautions

Do not use if safety seal is broken

Caution: Consult your physician before use if you are pregnant, lactating, have a medical condition, or if you’re taking any medication.

Consult a health care practitioner if you have a liver disorder, or if you have an iron deficiency.

Keep out of reach of children.

To report a serious adverse event or obtain product information, call 1-866-215-0450

Storage

Store tightly sealed in a cool, dry place

Directions: Take 1 capsule daily without food, or as directed by a qualified health care practitioner.

Formula

Discussion: Zen Theanine is L-theanine, a unique amino acid found primarily in green tea associated with promoting calm and relaxed alertness.* Made with Suntheanine, a 100% pure L-isomer-theanine.

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)

Suntheanine is a registered trademark of Taiyo International.

General Statements

Product of Canada

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

See for yourself

Zen Theanine by AOR Advanced Orthomolecular Research Premium label

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

Zen Theanine 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 Theanine by AOR Advanced Orthomolecular Research Premium

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.

Suntheanine L-Theanine

Interacts with
565 drugs
225 mg per serving

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 L-Theanine monograph & interactions

Other (inactive) ingredients: Microcrystalline Cellulose, Capsule. These complete the product’s ingredient list but are not active constituents.

Interaction report

Zen Theanine by AOR Advanced Orthomolecular Research Premium Drug Interactions

Want to check YOUR meds against Zen Theanine?

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
565Drugs
172 Moderate 393 Minor

Ingredients driving the most interactions

Suntheanine L-Theanine 565

Individual Drug Interactions

The ingredients in Zen Theanine interact with 565 drugs. Click any drug to see the details.

1 of the 1 ingredient in Zen Theanine interact with drugs. Each result below shows which ingredient is responsible. Suntheanine L-Theanine

Each ingredient & the kinds of drugs it affects

For each ingredient in Zen Theanine 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.

Suntheanine L-Theanine3 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 L-Theanine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for Zen Theanine, from the product label.

AOR Advanced Orthomolecular Research Premium

See all AOR Advanced Orthomolecular Research Premium products
Name
AOR Inc.
Street Address
30 Industrial West
City
Clifton
State
NJ
ZipCode
07012
Phone Number
1-866-215-0450
Pharmacist Counseling Corner

Zen Theanine by AOR Advanced Orthomolecular Research Premium: Common Questions

Does Zen Theanine by AOR Advanced Orthomolecular Research Premium interact with any medications?
Yes. Based on its ingredients, Zen Theanine has a known interaction with 565 medications. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
Zen Theanine contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take this if I'm pregnant or breastfeeding?
The safety data isn't there to say yes or no either way. The facts advise avoiding it, so talk with your doctor or pharmacist about your specific situation before taking it.
What are the most common side effects?
Headaches are the main one reported. Some people also experience drowsiness, sleep that lasts longer than usual, or more vivid dreams.
How long is it safe to take this?
L-theanine is generally well tolerated for short-term use in healthy adults, but we don't have good data on long-term safety, so that's worth discussing with your pharmacist.
Does this actually help with focus or anxiety?
For cognitive function, the evidence says it's possibly effective. For anxiety disorders, generalized anxiety, or OCD, there isn't enough reliable evidence yet to know if it works.

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

Not sure if Zen Theanine 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.

Zen Theanine label
Go deeper

The Full Monographs Behind Zen Theanine’s Ingredients

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

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 →
Sources

Sources & How We Checked

Zen Theanine'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 6 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.

Theanine 6 references
  1. Yokogoshi H, Kobayashi M. Hypotensive effect of gamma-glutamylethylamide in spontaneously hypertensive rats. Life Sci 1998;62:1065-8.
  2. Haskell, C. F., Kennedy, D. O., Milne, A. L., Wesnes, K. A., and Scholey, A. B. The effects of L-theanine, caffeine and their combination on cognition and mood. Biol.Psychol. 2008;77(2):113-122. PubMed
  3. Yokogoshi, H., Kato, Y., Sagesaka, Y. M., Takihara-Matsuura, T., Kakuda, T., and Takeuchi, N. Reduction effect of theanine on blood pressure and brain 5-hydroxyindoles in spontaneously hypertensive rats. Biosci.Biotechnol.Biochem. 1995;59(4):615-618. PubMed
  4. Lyon MR, Kapoor MP, Juneja LR. The effects of L-theanine (Suntheanine®) on objective sleep quality in boys with attention deficit hyperactivity disorder (ADHD): a randomized, double-blind, placebo-controlled clinical trial. Altern Med Rev. 2011;16(4):348-
  5. Hidese S, Ota M, Wakabayashi C, et al. Effects of chronic l-theanine administration in patients with major depressive disorder: an open-label study. Acta Neuropsychiatr 2017;29(2):72-9.
  6. Tsuchiya T, Honda H, Oikawa M, et al. Oral administration of the amino acids cystine and theanine attenuates the adverse events of S-1 adjuvant chemotherapy in gastrointestinal cancer patients. Int J Clin Oncol 2016;21(6):1085-90. PubMed

See these in context on the Theanine 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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