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Dietary supplement

L-Theanine 100 mg Ingredients & Drug Interactions

by The Vitamin Shoppe

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

L-Theanine 100 mg is a dietary supplement by The Vitamin Shoppe 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 100 mg by The Vitamin Shoppe

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 supplement contains one active ingredient: L-theanine 100 mg per capsule. L-Theanine is an amino acid found naturally in green tea that's thought to promote calm alertness.

The remaining ingredients—rice flour, hypromellose, carnauba wax, rice extract blend, microcrystalline cellulose, and silicon dioxide—are inactive fillers and capsule materials.

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 Theanine's own graded uses on its monograph.

Why this rating?
  • The label markets this product for: promotes relaxation and stress support.
  • We looked for evidence on: Generalized anxiety disorder (GAD), Stress, anxiety, calm.
  • The closest evidence on file: Theanine is rated "Insufficient Reliable Evidence To Rate" for Generalized anxiety disorder (GAD) (Natural Medicines).
  • Also on file: Theanine is rated "Insufficient Reliable Evidence To Rate" for Stress.

L-Theanine is possibly effective for boosting cognitive function, according to the evidence we hold. For age-related cognitive decline, Alzheimer disease, generalized anxiety disorder, obsessive-compulsive disorder, and cancer, there isn't enough reliable evidence to say whether it works or doesn't.

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 long-term safety hasn't been well studied. The most common side effects reported are headaches, drowsiness, longer sleep duration, and more vivid dreams.

One pediatric case of a subtle facial tic was reported after taking a much higher dose (400 mg daily), but the child had a history of tics and they stopped when the supplement was discontinued, so the link was unclear. There isn't enough safety data to know whether L-theanine is safe during pregnancy or while breastfeeding.

Talk with your doctor or pharmacist for personalized advice if you're pregnant, planning to become pregnant, or nursing.

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 taking L-Theanine, double-check with your doctor or pharmacist if you're on antihypertensive drugs (blood pressure medications)—theanine can lower pressure further and cause it to drop too much. Also confirm its use with any CNS depressants like sleep aids or anxiety medications, and with serotonergic drugs like certain antidepressants, even though serotonin interactions haven't been reported.

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.

L-Theanine might help with focus and alertness if the evidence holds up for you, but it's a supplement with limited long-term safety data. If you take blood pressure medication, sleep aids, or serotonin-affecting drugs, check with your doctor or pharmacist before starting it—the interaction risks matter most for those groups.

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-Theanine 100 mg, straight from the product label.

Brand The Vitamin Shoppe
Barcode (UPC) 766536018260
Net contents 60 Vegetable Capsule(s)
Market status On market
Date entered into DSLD Dec 22, 2019
DSLD ID 208720
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegetarian, 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 100 mg by The Vitamin Shoppe, 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 Vegetable Capsule(s)
Maximum serving Sizes:
1 Vegetable Capsule(s)
UPC/BARCODE
766536018260
IngredientAmount% DV
L-Theanine100 mg--

Other ingredients: Rice Flour, Hypromellose, Carnauba wax, Rice extract Blend, Microcrystalline Cellulose, Silicon Dioxide

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

Clinically studied Specialty

Formulation

Promotes relaxation Stress support

Non-GMO Gluten-free Dairy-free Soy-free Does not contain: Gluten, sugar, salt, animal derivatives, or preservatives.

FDA Statement of Identity

Dietary Supplement

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.

Suggested/Recommended/Usage/Directions

Directions: Take one (1) capsule two or three times daily.

Precautions

Warning: Consult your healthcare provider prior to use if you are pregnant, nursing, taking any medication or have any medical conditions.

Keep out of reach of children.

Tamper evident Do not use if outer seal is broken or missing.

Storage

Store in a cool, dry place.

Brand IP Statement(s)

Suntheanine is a registered trademark of Taiyo International. It is patented form of L-Theanine licensed by Taiyo International.

See for yourself

L-Theanine 100 mg by The Vitamin Shoppe label

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

What’s inside

The Ingredients in L-Theanine 100 mg by The Vitamin Shoppe

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

Serving size1 Vegetable Capsule(s) Dosage formCapsule Amounts shown are per serving.

L-Theanine

Interacts with
565 drugs
100 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: Rice Flour, Hypromellose, Carnauba wax, Rice extract Blend, Microcrystalline Cellulose, Silicon Dioxide. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Theanine 100 mg by The Vitamin Shoppe Drug Interactions

Want to check YOUR meds against L-Theanine 100 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 100 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 100 mg, from the product label.

The Vitamin Shoppe

See all The Vitamin Shoppe products
Name
Vitamin Shoppe, Inc.
City
Secaucus
State
NJ
ZipCode
07094
Phone Number
1-866-293-3367
Web Address
www.vitaminshoppe.com
Pharmacist Counseling Corner

L-Theanine 100 mg by The Vitamin Shoppe: Common Questions

Does L-Theanine 100 mg by The Vitamin Shoppe interact with any medications?
Yes. Based on its ingredients, L-Theanine 100 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 100 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.
Will L-Theanine make me drowsy?
Some people report drowsiness, increased sleep duration, and more vivid dreams after taking it. How much it affects you will depend on your individual response, but if you're sensitive to sedating effects or already take sleep aids, mention it to your pharmacist.
Is L-Theanine safe to take long-term?
It's generally well tolerated for short-term use in healthy adults, but long-term safety hasn't been well studied. If you're thinking of taking it regularly, that's worth discussing with your doctor or pharmacist.
Can I take L-Theanine while pregnant or breastfeeding?
There isn't enough safety data to know either way. Talk with your doctor or pharmacist for personalized advice if you're pregnant, planning to become pregnant, or nursing.
What is L-Theanine supposed to do?
L-Theanine, an amino acid from green tea, is possibly effective for cognitive function. For other uses like anxiety, cognitive decline, or Alzheimer disease, there isn't enough reliable evidence yet.
Does this supplement have any fillers?
Yes—the capsule contains rice flour, hypromellose, carnauba wax, rice extract blend, microcrystalline cellulose, and silicon dioxide as inactive ingredients.

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

Not sure if L-Theanine 100 mg 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.

L-Theanine 100 mg label
Go deeper

The Full Monographs Behind L-Theanine 100 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 100 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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