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Dietary supplement

L-Theanine 200 mg Ingredients & Drug Interactions

by Vitamin World

Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
The interaction bottom line Most serious interaction: Moderate

L-Theanine 200 mg is a dietary supplement by Vitamin World 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 L-Theanine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.

HelloPharmacist Scorecard of L-Theanine 200 mg by Vitamin World

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-theanine, an amino acid derived from tea that's used to support relaxation and mental focus. The capsule itself is made from vegetable cellulose and gelatin, with dicalcium phosphate as an inactive ingredient.

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

This product doesn't appear to be marketed for a specific use, so we graded Theanine's overall clinical evidence instead.

Moderate

Some clinical evidence supports Theanine for:

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.
  • Since the label doesn't commit to one use, we graded the ingredient's overall clinical evidence instead.
  • On file: Cognitive function — rated "Possibly Effective" (Natural Medicines).

L-Theanine is possibly effective for cognitive function — some research supports that it can help with focus and mental clarity. For age-related cognitive decline, Alzheimer disease, generalized anxiety disorder, obsessive-compulsive disorder, and cancer, the evidence we hold isn't strong enough to rate it either way.

If you're considering it for one of those uses, talk it over with your doctor about what the current science actually shows.

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 for short-term use, but we don't have solid long-term safety data. Common side effects include headaches, drowsiness, and vivid or longer dreams — a small number of people have reported these.

There isn't enough safety data to recommend this supplement during pregnancy or while breastfeeding. Talk with your doctor or pharmacist if you're pregnant, planning to become pregnant, or nursing to decide whether it's right for you.

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.

Check with your doctor or pharmacist before using this product if you're on blood pressure medications (antihypertensives), sedatives or sleep aids (CNS depressants), or antidepressants and related serotonergic drugs. L-Theanine may potentiate the blood pressure-lowering effect and could add to sedative effects.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with some supporting evidence behind its ingredients' uses. Moderate medication interactions have been identified, and safety information is well characterized.

L-Theanine may be worth considering if you're looking to support focus and mental clarity and you're not on blood pressure medications or sedatives. If you take any prescription drugs—especially for high blood pressure, sleep, anxiety, or depression—check your exact medications with your doctor or pharmacist before starting.

It's generally well tolerated short-term, but long-term safety isn't fully established.

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 Apr 25, 2013.

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-Theanine 200 mg, straight from the product label.

Brand Vitamin World
Barcode (UPC) 766443128809
Net contents 60 Rapid Release Capsule(s)
Market status On market
Date entered into DSLD Apr 25, 2013
DSLD ID 20557
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten Free, Dairy Free, Sugar 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-Theanine 200 mg by Vitamin World, 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
766443128809
IngredientAmount% DV
L-Theanine200 mg--

Other ingredients: Vegetable Cellulose, Dicalcium Phosphate, Gelatin, Contains <2% of

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

This product has been developed, manufactured and packaged by Vitamin World. Our world-class facilities allow us to control exactly what goes into each product. It is your assurance that you are getting the highest quality and freshest products. You have our guarantee!

- Supports a calm, relaxed mood*

As a natural phytochemical found in Japanese green tea, L-Theanine is a non-essential amino acid that supports a calm and relaxed mood.*

Formulation

No Artificial Color, Flavor or Sweetener, No Preservatives, No Sugar, No Starch, No Milk, No Lactose, No Soy, No Gluten, No Wheat, No Yeast, No Fish. Sodium Free.

Precautions

WARNING: If you are pregnant, nursing, taking any medications or have any medical condition, consult your doctor before use.

Discontinue use and consult your doctor if any adverse reactions occur.

Keep out of reach of children.

Do not use if seal under cap is broken or missing.

Storage

Store at room temperature.

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.

Brand IP Statement(s)

(C)2012 Vitamin World, Inc.

General

PROD. #12880 B12880 05D

Seals/Symbols

Get healthy.

QA QUALITY ASSURED

Formula

L-THEANINE 200 MG PER SERVING

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

DIRECTIONS: For adults, take two (2) capsules daily, preferably on an empty stomach.

See for yourself

L-Theanine 200 mg by Vitamin World label

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

What’s inside

The Ingredients in L-Theanine 200 mg by Vitamin World

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

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

L-Theanine

Interacts with
565 drugs
200 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...

L-Theanine monograph & interactions

Other (inactive) ingredients: Vegetable Cellulose, Dicalcium Phosphate, Gelatin, Contains <2% of. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Theanine 200 mg by Vitamin World Drug Interactions

Want to check YOUR meds against L-Theanine 200 mg?

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

Each ingredient & the kinds of drugs it affects

For each ingredient in L-Theanine 200 mg 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-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
The maker

Brand information

Manufacturer and brand details for L-Theanine 200 mg, from the product label.

Vitamin World

See all Vitamin World products
Phone Number
1-800-228-4533
Web Address
www.vitaminworld.com
Pharmacist Counseling Corner

L-Theanine 200 mg by Vitamin World: Common Questions

Does L-Theanine 200 mg by Vitamin World interact with any medications?
Yes. Based on its ingredients, L-Theanine 200 mg 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?
L-Theanine 200 mg 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.
Is L-Theanine safe to take while pregnant or breastfeeding?
There isn't enough safety data on L-Theanine during pregnancy or breastfeeding, so it's best to avoid it during these times. Talk with your doctor or pharmacist about whether it's appropriate for your situation.
What side effects might I experience?
The most common side effects are headaches and drowsiness. Some people also report longer sleep, increased dream activity, or vivid dreams. These effects are generally mild, but if they bother you, you can stop taking it and the symptoms should go away.
Does L-Theanine actually help with focus and mental clarity?
Yes — it's rated possibly effective for cognitive function based on available research. Results can vary from person to person, so give it a fair trial and see if you notice a difference yourself.
Can I take L-Theanine if I'm on blood pressure medication?
Not without checking first. L-Theanine may lower blood pressure, so combined with blood pressure meds it could lower your pressure too much. Talk with your doctor or pharmacist before starting it.
Will L-Theanine make me drowsy during the day?
It can — drowsiness is one of the reported side effects. Most people find it mild, and timing your dose (perhaps in the evening or before bed) may help if daytime sleepiness is a concern for you.

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

Not sure if L-Theanine 200 mg is safe with your meds?

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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-Theanine 200 mg label
Go deeper

The Full Monographs Behind L-Theanine 200 mg’s Ingredients

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

Sources

Sources & How We Checked

L-Theanine 200 mg'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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