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Dietary supplement

Theanine 200 mg Ingredients & Drug Interactions

by ProCaps

Theanine 200 mg label
See full label image
Capsule Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking 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

Theanine 200 mg is a dietary supplement by ProCaps 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.

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Check Your Meds Against Theanine 200 mg by ProCaps

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

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HelloPharmacist Scorecard of Theanine 200 mg by ProCaps

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 Sep 17, 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: L-theanine at 200 mg per capsule. Theanine is an amino acid found naturally in tea that's thought to support calm focus and mental clarity.

The capsule itself is made from gelatin.

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 relaxed focus naturally.
  • We looked for evidence on: Stress, Generalized anxiety disorder (GAD), Cognitive function, attention, mental clarity.
  • 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), Attention deficit-hyperactivity disorder (ADHD), Stress.

L-theanine is possibly effective for cognitive function based on the evidence we hold. For age-related cognitive decline, Alzheimer disease, generalized anxiety disorder, obsessive-compulsive disorder, and cancer, the evidence isn't established well enough to make a reliable claim — you'd want to talk with your doctor about whether it might help your specific situation.

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 how safe it is over the long run hasn't been well studied. The most common side effects reported are headaches, drowsiness, longer sleep duration, and increased dreaming.

One case of facial tics in a child was reported, but the child had a history of tics and the tics stopped after discontinuing theanine, so a direct link wasn't established. There isn't enough safety data to know whether 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 this product, double-check with your own doctor or pharmacist if you take blood pressure medications — theanine may strengthen their effect and lower your pressure too much. Also flag any sedating medications (sleep aids, anti-anxiety drugs, pain relievers) or antidepressants and other serotonin-affecting drugs you're on, since theanine could theoretically add to their effects, though reported cases are rare.

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.

Theanine might be worth considering if you're looking to support focus and calm, though evidence for some uses is still developing. The main caution is that it can lower blood pressure, so if you take blood pressure medication, you'll want to check with your own doctor or pharmacist before starting.

It's also best discussed with your healthcare provider if you take sedating medications or are pregnant or breastfeeding.

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 May 22, 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 Theanine 200 mg, straight from the product label.

Brand ProCaps
Barcode (UPC) 687198
Net contents 360 Easy-To-Swallow Capsule(s)
Market status On market
Date entered into DSLD May 22, 2020
DSLD ID 220043
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years)
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 Theanine 200 mg by ProCaps, 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
360
UPC/BARCODE
687198
IngredientAmount% DV
L-Theanine200 mg--

Other ingredients: Gelatin 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.
Suggested/Recommended/Usage/Directions

Suggested Use Consume one capsule daily or as recommended by your physician. This product is most effective as part of a healthy diet and active lifestyle. For questions about the use of this product call 800.332.7799.

General Statements

For over 40 years Unsurpassed purity, quality and efficacy 100% solar production | zero carbon footprint We remain uniquely committed to you and the planet. You have my unwavering promise. Andrew Lessman, Founder Questions? | Reorders? 800-800-1200 www.procapslabs.com HSN www.HSN.com 800.944.9999 www.QVC.com 800.345.1515

Formula

200 mg of soothing Theanine

Andrew Lessman's Theanine provides 200 mg of pure Theanine - one of the most uniquely beneficial and unusual of amino acids. First of all, unlike other amino acids, Theanine is not a building block of protein, but is almost exclusively found in the tea plant (Camellia sinensis) where it accounts for both its distinctive flavor, as well as its unique calming properties. Plus, because Theanine can cross the blood brain barrier, it can deliver its beneficial properties directly to the brain and nervous system. Theanine has been shown to enhance alpha brain-wave activity, which is associated with a relaxed, but still focused and alert state. Theanine promotes the production of the neurotransmitters dopamine and serotonin, which support relaxation and calm. The observation that the caffeine in green tea is less intense than that of coffee results from green tea's abundance of Theanine. In fact Theanine is often used to reduce the uncomfortable effects of caffeine and to support a relaxed state. Theanine can also help to diminish perceived stress and tension while promoting calm attention and focus. In short, Theanine naturally supports the brain and its neurotransmitters promoting calm, relaxed focus without drowsiness.

Formulation

Calm relaxed focus - naturally

Contains no additives or common allergens of any kind

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.

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

See for yourself

Theanine 200 mg by ProCaps label

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

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 Theanine 200 mg by ProCaps

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 container360 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: Gelatin Capsule. These complete the product’s ingredient list but are not active constituents.

Interaction report

Theanine 200 mg by ProCaps Drug Interactions

Want to check YOUR meds against 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

L-Theanine 565

Individual Drug Interactions

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

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

Each ingredient & the kinds of drugs it affects

For each ingredient in 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
L-Theanine full monograph & interactions
The maker

Brand information

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

ProCaps

See all ProCaps products
Name
ProCaps Labs
City
Henderson
State
NV
ZipCode
89011
Phone Number
800-800-1200
Web Address
ProCapsLabs.com
Pharmacist Counseling Corner

Theanine 200 mg by ProCaps: Common Questions

Does Theanine 200 mg by ProCaps interact with any medications?
Yes. Based on its ingredients, 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?
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.
What is L-theanine and what is it supposed to do?
L-theanine is an amino acid found in tea. This product contains it to support cognitive function — helping with focus and mental clarity. It's possibly effective for that purpose based on available evidence, though research on some other uses (like anxiety or age-related memory loss) isn't conclusive yet.
What side effects might I experience?
Most commonly, headaches, drowsiness, longer sleep, and more vivid dreams have been reported. A single case of facial tics was reported in a child but wasn't confirmed to be caused by theanine. Overall, it's generally well tolerated in healthy adults over the short term.
Is it safe to take theanine if I'm pregnant or breastfeeding?
There isn't enough safety data to know either way. It's best to talk with your doctor or pharmacist before taking it if you're pregnant, planning to become pregnant, or nursing — they can give you personalized advice based on your situation.
Can I take theanine long-term?
Short-term use in healthy adults is generally well tolerated, but how safe it is over the long run hasn't been well studied. If you're thinking about taking it for an extended period, check in with your doctor or pharmacist.
Will theanine interact with my blood pressure medication?
Theanine can lower blood pressure on its own, so it may strengthen the effect of blood pressure medications. Before you start, run this by your own doctor or pharmacist to make sure your pressure won't drop too low.
Does this product have any fillers or other inactive ingredients?
The capsule is made from gelatin. There are no other inactive ingredients listed.

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.

Theanine 200 mg label
Go deeper

The Full Monographs Behind 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

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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