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Dietary supplement

SunTheanine 150 mg Ingredients & Drug Interactions

by Tomorrow's Nutrition

SunTheanine 150 mg label
See full label image
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 SunTheanine 150 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

SunTheanine 150 mg is a dietary supplement by Tomorrow's Nutrition 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 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 SunTheanine 150 mg by Tomorrow's Nutrition

Ask about any prescription or over-the-counter medication and we check it for interactions with SunTheanine 150 mg by Tomorrow's Nutrition — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of SunTheanine 150 mg by Tomorrow's Nutrition

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.

SunTheanine 150 mg is a single-ingredient supplement containing Suntheanine L-theanine — a naturally occurring amino acid found in green tea. Each capsule delivers 150 mg of this ingredient in a vegetable cellulose capsule with rice extract as an inactive ingredient.

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: stress relief, sleep quality, and mental focus.
  • We looked for evidence on: Stress, Insomnia, Generalized anxiety disorder (GAD), Cognitive function, Sleep quality, Concentration — and 1 related terms.
  • 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), Insomnia, Stress.

L-theanine is possibly effective for cognitive function — the one area where we have reasonable evidence. For age-related cognitive decline, Alzheimer's disease, generalized anxiety disorder, obsessive-compulsive disorder, and cancer, the evidence isn't established in our data, so we can't say whether it works for those uses.

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 we don't have solid long-term safety data. The most common side effects are headaches, drowsiness, increased sleep duration, and vivid dreams.

One pediatric case of facial tics was reported but appeared unrelated to the supplement. There isn't enough safety data to know whether L-theanine is safe during pregnancy or breastfeeding, so it's best to avoid it during these times and discuss any supplement use with your doctor or pharmacist.

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 SunTheanine, double-check your medications with your doctor or pharmacist if you take blood pressure-lowering drugs — theanine may enhance their effect and drop your pressure too low. Also flag any sedating medications (CNS depressants like sleep aids or anti-anxiety drugs) or serotonergic medications (most antidepressants and some migraine or pain medications), though the risk with the latter two categories is lower.

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.

SunTheanine might be worth considering if you're looking for a cognitive boost, since it's possibly effective for cognitive function. If you take blood pressure medication, sleep aids, anti-anxiety medication, or an antidepressant, check with your own doctor or pharmacist before starting — theanine could change how those drugs work.

It's generally well tolerated short-term, but talk it over with your healthcare provider to make sure it's right for you.

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 25, 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 SunTheanine 150 mg, straight from the product label.

Brand Tomorrow's Nutrition
Barcode (UPC) 850236004002
Net contents 60 Veggie Capsule(s)
Market status On market
Date entered into DSLD Apr 25, 2019
DSLD ID 201468
Product type Non-nutrient/non-botanical
Supplement form Capsule
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Kosher, Gluten Free, Dairy 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 SunTheanine 150 mg by Tomorrow's Nutrition, 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
60
UPC/BARCODE
850236004002
IngredientAmount% DV
Suntheanine L-Theanine150 mg--

Other ingredients: Vegetable Cellulose, Rice extract

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.
Precautions

Warning: If pregnant, nursing, or taking prescription drugs, consult your healthcare practitioner prior to use.

Do not use if safety seal is broken or missing.

Keep out of the reach of children.

Formula

Tomorrow's Nutrition Suntheanine delivers 150 mg of clinically proven, award winning and patented L-theanine.

L-Theanine 150

OK

General Statements

Supports stress relief Improves quality of sleep Improves mental focus

Improves focus & concentration Reduces stress without drowsiness

General

Rev. 7

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.

FDA Statement of Identity

Dietary Supplement

Suggested/Recommended/Usage/Directions

Recommendations: Adults, as a dietary supplement, take once or twice daily.

Formulation

Contains No: artificial sweeteners, diary, wheat or yeast.

Gluten Free Non-Dairy Non-GMO

Vegan

Storage

Store in a cool dry place.

Brand IP Statement(s)

Suntheanine is a trademark of Taiyo International, Inc.

Seals/Symbols

OK

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

See for yourself

SunTheanine 150 mg by Tomorrow's Nutrition label

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

SunTheanine 150 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 SunTheanine 150 mg by Tomorrow's Nutrition

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.

Suntheanine L-Theanine

Interacts with
565 drugs
150 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...

Suntheanine L-Theanine monograph & interactions

Other (inactive) ingredients: Vegetable Cellulose, Rice extract. These complete the product’s ingredient list but are not active constituents.

Interaction report

SunTheanine 150 mg by Tomorrow's Nutrition Drug Interactions

Want to check YOUR meds against SunTheanine 150 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 L-Theanine 565

Individual Drug Interactions

The ingredients in SunTheanine 150 mg interact with 565 drugs. Click any drug to see the details.

1 of the 1 ingredient in SunTheanine 150 mg interact with drugs. Each result below shows which ingredient is responsible. Suntheanine L-Theanine

Each ingredient & the kinds of drugs it affects

For each ingredient in SunTheanine 150 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.

Suntheanine 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
Suntheanine L-Theanine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for SunTheanine 150 mg, from the product label.

Tomorrow's Nutrition

See all Tomorrow's Nutrition products
Name
Tomorrow's Nutrition
City
Minneapolis
State
MN
Phone Number
888-380-2322
Web Address
www.tomorrowsnutrition.com
Pharmacist Counseling Corner

SunTheanine 150 mg by Tomorrow's Nutrition: Common Questions

Does SunTheanine 150 mg by Tomorrow's Nutrition interact with any medications?
Yes. Based on its ingredients, SunTheanine 150 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?
SunTheanine 150 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 SunTheanine make me drowsy?
Drowsiness is one of the reported side effects, along with increased sleep duration and vivid dreams. Most people tolerate it well, but if you're sensitive to sedation, start low and see how you feel — especially if you already take sleep aids.
Can I take this while pregnant or breastfeeding?
There isn't enough safety data to know either way. It's best to avoid it during pregnancy and breastfeeding and talk with your doctor or pharmacist about whether it's right for you at this time.
Is L-theanine actually different from regular theanine?
Suntheanine is a branded form of L-theanine — the specific amino acid ingredient used in research and supplements. It's the active form your body uses.
Does this supplement work for anxiety?
We don't have enough reliable evidence to say whether L-theanine works for generalized anxiety disorder or OCD. The evidence we hold is insufficient to rate it for those uses.
What if I get a headache after taking it?
Headaches are a known side effect of oral L-theanine. If it persists or bothers you, stop taking it and let your doctor or pharmacist know.
Is this safe for long-term use?
L-theanine is well tolerated in healthy adults for short-term use, but we don't have solid data on safety with long-term daily use. Discuss ongoing use with your pharmacist or doctor.

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

Not sure if SunTheanine 150 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.

SunTheanine 150 mg label
Go deeper

The Full Monographs Behind SunTheanine 150 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

SunTheanine 150 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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