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Dietary supplement

L-Theanine 200 mg Ingredients & Drug Interactions

by Sports Research

L-Theanine 200 mg label
See full label image
Softgel Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 23, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking L-Theanine 200 mg 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

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

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Check Your Meds Against L-Theanine 200 mg by Sports Research

Ask about any prescription or over-the-counter medication and we check it for interactions with L-Theanine 200 mg by Sports Research — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of L-Theanine 200 mg by Sports Research

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 Jul 11, 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.

This product contains one active ingredient: Suntheanine, which is L-theanine — an amino acid found naturally in tea. The capsule also contains coconut oil, gelatin, glycerin, purified water, and beeswax as inactive ingredients that help form and deliver the softgel.

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 supporting cognitive function. For other uses — age-related cognitive decline, Alzheimer disease, generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), and cancer — the evidence isn't established well enough in our data to rate it one way or the other.

If you're considering it for any of those other purposes, that's a good conversation to have with your pharmacist or doctor.

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

There's one case report of mild facial tics in a child taking a higher dose, but the tics stopped when the supplement was discontinued, and the child had a history of tics — so the link wasn't clear. There isn't enough safety data on L-theanine in pregnancy or while breastfeeding, so it's best to avoid it during those times unless your doctor or pharmacist advises otherwise.

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.

Double-check this product if you take blood pressure medications (Moderate interaction) — theanine could lower your pressure further. Also flag any sedating medications like sleep aids or anxiety drugs (Minor), and serotonergic antidepressants (Minor) — though the serotonin effect is unclear.

Use the search tool to verify your exact medications.

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 is possibly helpful for cognitive function and is generally well tolerated short-term in healthy adults. If you take blood pressure medications, sedating drugs, or certain antidepressants, check your specific prescriptions with the tool on this page before you start.

Not enough is known about long-term use, so talk with your pharmacist if you're planning to take it regularly.

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 Feb 23, 2025.

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 Sports Research
Barcode (UPC) 023249010173
Net contents 60 Softgel(s)
Market status On market
Date entered into DSLD Feb 23, 2025
DSLD ID 326262
Product type Non-nutrient/non-botanical
Supplement form Softgel Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), Gluten 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 Sports Research, 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 Softgel(s)
Maximum serving Sizes:
1 Softgel(s)
Servings per container
60
UPC/BARCODE
023249010173
IngredientAmount% DV
Suntheanine200 mg--

Other ingredients: Coconut Oil, Virgin, Gelatin, Glycerin, Water, Purified, Beeswax

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.
Suggested/Recommended/Usage/Directions

Suggested Use: Adults take 1 softgel daily with or without food, or as recommended by a qualified healthcare professional.

Seals/Symbols

IGEN Non-GMO Tested

Formulation

Quality matters: IGEN Non-GMO Tested Non-GMO tested Gluten-free

Third party tested cGMP Compliant

Double strength When compared to standard L-Theanine softgels with only 100mg content. Supports relaxation & focus

NON BPA Gluten-free Non-GMO

Proudly manufactured in the USA with carefully selected ingredients of domestic and international origins.

Precautions

Caution: Keep out of reach of children and pets.

Caution: Keep out of reach of children and pets. Do not exceed recommended daily intake. Do not use if safety seal is damaged or missing.

Consult with a qualified healthcare professional prior to using this product, especially if you are pregnant, nursing, have a diagnosed medical condition, are taking a prescription medication.

Contains: Tree nuts (coconut).

Storage

Store at room temperature, in a dry place. Protect product from excessive heat, freezing, humidity and light.

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.

General Statements

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@sportsresearch

Formula

L-Theanine 200mg per serving Suntheanine

FDA Statement of Identity

Dietary Supplement

Brand IP Statement(s)

Suntheanine is a registered trademark of Taiyo International, Inc.

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

See for yourself

L-Theanine 200 mg by Sports Research label

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

L-Theanine 200 mg 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 L-Theanine 200 mg by Sports Research

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

Serving size1 Softgel(s) Dosage formSoftgel Capsule Servings per container60 Amounts shown are per serving.

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

Other (inactive) ingredients: Coconut Oil, Virgin, Gelatin, Glycerin, Water, Purified, Beeswax. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Theanine 200 mg by Sports Research 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

Suntheanine 565

Individual Drug Interactions

The ingredients in L-Theanine 200 mg interact with 565 drugs. Click any drug to see the details.

1 of the 1 ingredient in L-Theanine 200 mg interact with drugs. Each result below shows which ingredient is responsible. Suntheanine

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.

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
The maker

Brand information

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

Sports Research

See all Sports Research products
Name
Sports Research
Street Address
784 Channel St.
City
San Pedro
State
CA
ZipCode
90731
Phone Number
(310) 519-1484
Web Address
sportsresearch.com
Pharmacist Counseling Corner

L-Theanine 200 mg by Sports Research: Common Questions

Does L-Theanine 200 mg by Sports Research 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.
Can I take this if I'm pregnant or breastfeeding?
There isn't enough safety data on L-theanine during pregnancy or breastfeeding. The advice is to avoid it during those times. Talk with your doctor or pharmacist before use if you're pregnant, planning pregnancy, or nursing.
What's Suntheanine, and is it different from regular L-theanine?
Suntheanine is a branded form of L-theanine — the amino acid that occurs naturally in tea. For practical purposes, it's the active ingredient that does the work in this product.
Will this make me drowsy?
Some people report drowsiness or increased sleep after taking L-theanine, though not everyone experiences it. You may also notice more vivid dreams or headaches. Starting with one dose and seeing how you feel is a good idea.
How long does it take to work?
The facts we have don't detail how quickly you'll notice an effect. That's a good question for your pharmacist, especially if you're trying it for cognitive support.
Is this safe to take long-term?
L-Theanine is generally well tolerated for short-term use in healthy adults, but long-term safety hasn't been studied closely. If you're thinking of taking it regularly, check in with your pharmacist.
Does it really help with focus and thinking?
L-Theanine is rated possibly effective for cognitive function — meaning there's some evidence, but it's not definitive. For anxiety or other conditions, the evidence we hold isn't strong enough to rate either way.

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.

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

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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