Interactions on record — worth a quick check against your medications. Based on 1 of 2 ingredients. Check your meds →
Dietary supplement

L-Theanine Relax 200 mg Refreshing Mint Ingredients & Drug Interactions

by GNC

L-Theanine Relax 200 mg Refreshing Mint label
See full label image
Tablet Or Pill Category: Non-nutrient/non-botanical
Most serious interaction: Moderate
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking L-Theanine Relax 200 mg Refreshing Mint 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 Relax 200 mg Refreshing Mint is a dietary supplement by GNC with 2 active ingredients. 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 L-Theanine Relax 200 mg Refreshing Mint by GNC

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

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of L-Theanine Relax 200 mg Refreshing Mint by GNC

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 Aug 13, 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.

L-Theanine Relax contains one active ingredient: L-theanine 200 mg per tablet. L-theanine is an amino acid found naturally in tea that's thought to promote relaxation and calm without causing drowsiness.

The tablet also contains inactive ingredients — dextrose, mannitol, cellulose, stearic acid, natural flavor, sucralose, silicon dioxide, and magnesium stearate — which serve as fillers and binders.

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: relaxation and stress relief.
  • We looked for evidence on: Generalized anxiety disorder (GAD), Stress, anxiety, sleep quality, mental calm.
  • The closest evidence on file: Theanine is rated "Insufficient Reliable Evidence To Rate" for Anxiety (Natural Medicines).
  • Also on file: Theanine is rated "Insufficient Reliable Evidence To Rate" for Generalized anxiety disorder (GAD), Stress.

L-theanine is possibly effective for supporting cognitive function, according to the evidence we have on file. For age-related cognitive decline, Alzheimer disease, generalized anxiety disorder, obsessive-compulsive disorder, and cancer, the evidence is insufficient to rate whether it works — we simply don't have enough reliable data to say one way or the other.

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, though long-term safety hasn't been well studied. Some people report headaches, drowsiness, longer sleep, or more vivid dreams.

One pediatric case of facial tics was reported after starting theanine, but the child had a history of tics and they stopped when the supplement was discontinued, so a direct link wasn't established. The safety data advises against using this supplement during pregnancy or while breastfeeding — there isn't enough information to know it's safe for either.

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 with your doctor or pharmacist before taking L-Theanine Relax if you use blood pressure medications (the moderate concern here), sedatives or other CNS depressants, or serotonergic antidepressants. The blood pressure interaction is the most serious — theanine can potentiate their effect.

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 Relax may help with cognitive function and is generally well tolerated for short-term use in healthy adults. If you take blood pressure medication or sedatives, check with your doctor or pharmacist before starting — theanine can lower blood pressure and may amplify sedative effects.

A conversation with your own healthcare provider about whether this fits your health picture is a smart next step.

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 Jun 23, 2017.

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 Relax 200 mg Refreshing Mint, straight from the product label.

Brand GNC
Barcode (UPC) 048107163259
Net contents 60 Chewable Tablet(s)
Market status On market
Date entered into DSLD Jun 23, 2017
DSLD ID 75176
Product type Non-nutrient/non-botanical
Supplement form Tablet Or Pill
Dietary claims / uses All Other
Intended target group(s) Adult (18 - 50 Years), 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 Relax 200 mg Refreshing Mint by GNC, 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:
4 Tablet(s)
Maximum serving Sizes:
4 Tablet(s)
Servings per container
15
UPC/BARCODE
048107163259
IngredientAmount% DV
Sugar0 Gram(s)--
L-Theanine200 mg--

Other ingredients: Dextrose Monohydrate, Mannitol, Cellulose, Stearic Acid, Natural Flavor, Sucralose, Silicon Dioxide, Magnesium Stearate

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

New!

Natural flavor

Actual size

Formulation

Sugar free

FDA Statement of Identity

Dietary Supplement

General

CODE 504399 HQG

Suggested/Recommended/Usage/Directions

Directions: As a dietary supplement, chew four tablets daily.

Formula

^Adds a trivial amount of sugar.

Precautions

Warning: Consult your physician prior to using this product if you are pregnant, nursing, taking medication, or have a medical condition.

Discontinue use two weeks prior to surgery. Do not exceed recommended daily dosage.

Keep out of reach of children.

Storage

Store in a cool, dry place.

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 Relax 200 mg Refreshing Mint by GNC label

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

L-Theanine Relax 200 mg Refreshing Mint 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 Relax 200 mg Refreshing Mint by GNC

These are the 2 active ingredients this product is made of. Select any to open its full monograph.

Serving size4 Tablet(s) Dosage formTablet Or Pill Servings per container15 Amounts shown are per serving.

Most supplement products combine several ingredients, and a medication can interact with the product through any one of them. Each ingredient below shows whether it has known drug interactions.

Sugar

0 Gram(s) 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: Dextrose Monohydrate, Mannitol, Cellulose, Stearic Acid, Natural Flavor, Sucralose, Silicon Dioxide, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Theanine Relax 200 mg Refreshing Mint by GNC Drug Interactions

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

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 L-Theanine Relax 200 mg Refreshing Mint interact with 565 drugs. Click any drug to see the details.

1 of the 2 ingredients in L-Theanine Relax 200 mg Refreshing Mint 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 L-Theanine Relax 200 mg Refreshing Mint 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 L-Theanine Relax 200 mg Refreshing Mint, from the product label.

GNC

See all GNC products
Name
General Nutrition Corporation
City
Pittsburgh
State
PA
ZipCode
15222
Phone Number
1-888-462-2548
Web Address
www.gnc.com
Pharmacist Counseling Corner

L-Theanine Relax 200 mg Refreshing Mint by GNC: Common Questions

Does L-Theanine Relax 200 mg Refreshing Mint by GNC interact with any medications?
Yes. Based on its ingredients, L-Theanine Relax 200 mg Refreshing Mint 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 Relax 200 mg Refreshing Mint contains 2 active ingredients, and an interaction can come from any of them. We check every ingredient, combine the results into one list per medication, and show which ingredient and mechanism is 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?
Not based on the safety data on file. There isn't enough information to know whether L-theanine is safe during pregnancy or breastfeeding, so it's best to avoid it and talk with your doctor or pharmacist about what's right for you.
Will this make me drowsy?
Some people report drowsiness and increased sleep duration after taking L-theanine, though it's not guaranteed. If you're sensitive to sedating effects, start carefully and see how you feel, or talk it over with your pharmacist first.
How long is it safe to use?
L-theanine is generally well tolerated in healthy adults for short-term use. Long-term safety hasn't been well studied, so if you're thinking of taking it for weeks or months, check in with your doctor or pharmacist.
What is L-theanine and where does it come from?
L-theanine is an amino acid found naturally in tea leaves. It's thought to promote relaxation and calm without the drowsiness that caffeine might cause.
Does this actually help with memory or focus?
L-theanine is possibly effective for cognitive function based on the evidence we have. For other brain-related concerns like age-related decline or Alzheimer disease, the evidence is too limited to say whether it works.

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

Not sure if L-Theanine Relax 200 mg Refreshing Mint 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 Relax 200 mg Refreshing Mint label
Go deeper

The Full Monographs Behind L-Theanine Relax 200 mg Refreshing Mint’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 Relax 200 mg Refreshing Mint'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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