L-Theanine 100 mg Ingredients & Drug Interactions
What is this page for?
First and foremost: checking L-Theanine 100 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
L-Theanine 100 mg is a dietary supplement by Life Extension 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.
Check Your Meds Against L-Theanine 100 mg by Life Extension
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Theanine 100 mg by Life Extension — and tell you which ingredient is responsible.
AI summaries are generated from our interaction database for education only — always confirm with your pharmacist. How we use AI
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HelloPharmacist Scorecard of L-Theanine 100 mg by Life Extension
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.
What’s inside
Full disclosure
This product contains one active ingredient: L-Theanine, an amino acid naturally found in green tea. The capsule also holds inactive ingredients (microcrystalline cellulose, cellulose, silica, and stearate) that serve as binders and fillers.
Does it work?
Moderate evidence
L-Theanine is possibly effective for cognitive function—meaning there's some evidence but it's not definitive. For age-related cognitive decline, Alzheimer disease, generalized anxiety disorder (GAD), obsessive-compulsive disorder (OCD), and cancer support, the evidence we hold is insufficient to rate whether it works.
If you're considering it for one of those conditions, talk with your pharmacist about what the current research shows.
How safe is it?
Well-documented data
L-Theanine is generally well tolerated in healthy adults for short-term use, but long-term safety hasn't been thoroughly studied. The most common side effects are headaches, drowsiness, longer sleep, and more vivid dreams.
One pediatric case reported facial tics, though the child had a history of tics and they stopped when the supplement was discontinued, so the connection was unclear. There isn't enough safety data to recommend L-Theanine during pregnancy or while breastfeeding—talk with your doctor or pharmacist before using it in either situation.
Meds to double-check
Moderate interaction found
Check with your pharmacist if you take blood pressure–lowering drugs (antihypertensives)—L-Theanine may enhance their effect. Also flag any CNS depressants, like sedatives or sleep aids.
While serotonergic drugs (SSRIs, SNRIs) haven't shown problems with L-Theanine in reports, the evidence is mixed, so mention them too.
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.
L-Theanine may help with focus and mental clarity, but the evidence is modest and limited. If you take blood pressure medication or sedatives, you'll need to check with your pharmacist first.
It's generally well tolerated for short-term use, though long-term effects aren't well 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 24, 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
General information
Key facts about L-Theanine 100 mg, straight from the product label.
| Brand | Life Extension |
|---|---|
| Barcode (UPC) | 737870168362 |
| Net contents | 60 Vegetarian Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Apr 24, 2025 |
| DSLD ID | 328523 |
| 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 |
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 Life Extension, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Theanine | 100 mg | -- |
Other ingredients: Microcrystalline Cellulose, Cellulose, Silica, Stearate
Tap any ingredient to jump to its full detail below.
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
Scan for product info
Precautions
Read the entire label and follow the directions carefully prior to use.
Warnings: Keep out of reach of children.
Do not exceed recommended dose. Do not purchase if outer seal is broken or damaged.
When using nutritional supplements, please consult with your physician if you are undergoing treatment for a medical condition or if you are pregnant or lactating.
To report a serious adverse event or obtain product information, contact 1-866-280-2852.
Suggested/Recommended/Usage/Directions
Directions: Take one (1) capsule one to four times daily, or as recommended by a healthcare practitioner.
Storage
Store tightly closed in a cool, dry place.
Formulation
Gluten free Non GMO Le certified
Promotes a calming and mood enhancing effect
Seals/Symbols
Non GMO Le certified
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.
L-Theanine 100 mg by Life Extension label
The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.
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)The Ingredients in L-Theanine 100 mg by Life Extension
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 container60 Amounts shown are per serving.
L-Theanine
Interacts with565 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 dro...
L-Theanine monograph & interactionsOther (inactive) ingredients: Microcrystalline Cellulose, Cellulose, Silica, Stearate. These complete the product’s ingredient list but are not active constituents.
L-Theanine 100 mg by Life Extension Drug Interactions
HelloPharmacist Interaction Report
Life Extension's L-Theanine 100 mg does interact with certain medications.
The main concern is with blood pressure–lowering drugs (antihypertensives). L-Theanine may lower blood pressure on its own, and using it alongside blood pressure medications could push your pressure too low.
Animal studies support this risk, though human data is limited.
Read the full breakdown — every affected drug type, severity by severity
L-Theanine may also have additive sedative effects with CNS depressants (sedatives, sleep aids, certain pain relievers). The concern is theoretical—it's not clear how often this matters in real life—but it's worth flagging.
Additionally, while studies conflict on whether L-Theanine affects serotonin, no cases of serotonin syndrome have been reported with it, even alongside serotonergic drugs (like SSRIs).
Altogether, these interactions span 563 individual medications. Use the medication checker on this page to look up your exact prescriptions before starting.
Check your own medications below · Editorial policy · How we use AI
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 checkerIngredients driving the most interactions
Individual Drug Interactions
The ingredients in L-Theanine 100 mg interact with 565 drugs. Click any drug to see the details.
1 of the 1 ingredient in L-Theanine 100 mg interact with drugs. Each result below shows which ingredient is responsible. L-Theanine
AcebutololRhotral, Sectral
How Acebutolol interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Acebutolol interactionAcetazolamideAk-Zol, Diamox
How Acetazolamide interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineCns Depressants, Antihypertensive Drugs Moderate
Interaction Summary
Theoretically, theanine might have additive sedative effects when used in conjunction with CNS depressants.
Read the full L-theanine + Acetazolamide interactionAliskirenTekturna
How Aliskiren interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Aliskiren interactionAmbrisentanLetairis, Volibris
How Ambrisentan interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Ambrisentan interactionAmilorideAmilamont, Midamor
How Amiloride interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amiloride interactionAmiloride, HydrochlorothiazideAmil-Co, Amilzide, Moduret 25, Moduretic
How Amiloride, Hydrochlorothiazide interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amiloride, Hydrochlorothiazide interactionAmlodipineNorliqva
How Amlodipine interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amlodipine interactionAmlodipine BenzoateKaterzia
How Amlodipine Benzoate interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amlodipine Benzoate interactionAmlodipine BesilateIstin
How Amlodipine Besilate interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amlodipine Besilate interactionAmlodipine BesylateNorvasc
How Amlodipine Besylate interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amlodipine Besylate interactionAmlodipine Besylate, BenazeprilLotrel
How Amlodipine Besylate, Benazepril interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amlodipine Besylate, Benazepril interactionAmlodipine, CelecoxibConsensi
How Amlodipine, Celecoxib interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Amlodipine, Celecoxib interactionAmmonium ChlorideAmmonium Chloride
How Ammonium Chloride interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Ammonium Chloride interactionAprocitentanTryvio
How Aprocitentan interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Aprocitentan interactionAtenololAtenix, Tenormin
How Atenolol interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Atenolol interactionAtenolol, ChlortalidoneAtenixCo, Tenoret 50, Totaretic
How Atenolol, Chlortalidone interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Atenolol, Chlortalidone interactionAtenolol, ChlorthalidoneTenoretic
How Atenolol, Chlorthalidone interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Atenolol, Chlorthalidone interactionAzilsartanEdarbi
How Azilsartan interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Azilsartan interactionAzilsartan, ChlorthalidoneEdarbyclor
How Azilsartan, Chlorthalidone interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Azilsartan, Chlorthalidone interactionBenazeprilLotensin
How Benazepril interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Benazepril interactionBenazepril, HydrochlorothiazideLotensin HCT
How Benazepril, Hydrochlorothiazide interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Benazepril, Hydrochlorothiazide interactionBendroflumethiazideAprinox, Naturetin, Neo-NaClex
How Bendroflumethiazide interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Bendroflumethiazide interactionBendroflumethiazide, NadololCorzide
How Bendroflumethiazide, Nadolol interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Bendroflumethiazide, Nadolol interactionBendroflumethiazide, Rauwolfia SerpentinaRauzide
How Bendroflumethiazide, Rauwolfia Serpentina interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Bendroflumethiazide, Rauwolfia Serpentina interactionBenzthiazideExna
How Benzthiazide interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Benzthiazide interactionBetaxololBetoptic, Kerlone
How Betaxolol interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Betaxolol interactionBisoprololZebeta
How Bisoprolol interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Bisoprolol interactionBisoprolol, HydrochlorothiazideZiac
How Bisoprolol, Hydrochlorothiazide interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Bisoprolol, Hydrochlorothiazide interactionBosentanTracleer
How Bosentan interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Bosentan interactionBumetanideBurinex
How Bumetanide interacts with L-Theanine 100 mg — through 1 ingredient. Tap an ingredient for the detail:
L-theanineAntihypertensive Drugs Moderate
Interaction Summary
Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.
Read the full L-theanine + Bumetanide interactionEach 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-Theanine
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.
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.
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.
Brand information
Manufacturer and brand details for L-Theanine 100 mg, from the product label.
Life Extension
See all Life Extension products- Name
- Quality Supplements and Vitamins, Inc.
- City
- Ft. Lauderdale
- State
- FL
- ZipCode
- 33309
- Phone Number
- 1-866-280-2852
- Web Address
- LifeExtension.com
L-Theanine 100 mg by Life Extension: Common Questions
Does L-Theanine 100 mg by Life Extension interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Can I take this while pregnant or breastfeeding?
What side effects might I notice?
Will this help with anxiety?
How long until I notice a difference?
Is this safe to take long-term?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Theanine 100 mg is safe with your meds?
Our pharmacists answer your medication & supplement questions — free.
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.
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 & 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.
- NIH Dietary Supplement Label Database (DSLD) — The official product label on file for this supplement.
- Natural Medicines (Therapeutic Research Center) — Evidence-graded clinical reference behind the ingredient interaction data.
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
- Yokogoshi H, Kobayashi M. Hypotensive effect of gamma-glutamylethylamide in spontaneously hypertensive rats. Life Sci 1998;62:1065-8.
- 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
- 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
- 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-
- 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.
- 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
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