Drug & supplement interaction

Theanine + Galantamine

Galantamine brand names: Reminyl, Razadyne.

No Known Interaction
Medically reviewed by · Updated July 2026 · Pair last verified Sep 13, 2026
The bottom line No known interaction

We found no known interaction between Theanine and Galantamine in our sources. Absence of a documented interaction is not the same as proven safety, and does not guarantee one does not exist. Do not start, stop, or change a medication or supplement based on this page; confirm with your pharmacist or doctor first. Additionally, although there is no interaction, the label for Galantamine states a food rule worth keeping to, and the two are separately associated with some of the same side effects, which would make a new symptom harder to attribute to one or the other.

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Interaction report

Theanine and Galantamine

We checked these two against our interaction database. Here is what we found.

No Known Interaction Found

We did not find a documented interaction between Galantamine and Theanine in our sources. This does not guarantee that the combination is completely free of risk — there is often limited research on supplements and herbal products, especially around drug interactions.

If you decide to take both, the practical routine is simple: add one new thing at a time and note the date you started it. If the combination is going to disagree with you, it usually shows in the first days to a couple of weeks — and a start date turns “I’ve been feeling off” into something a pharmacist can actually work with. Do not stop a prescribed medicine on your own.

Always talk with your pharmacist or doctor before making changes to your medications or supplements, particularly if you take several medications or have an ongoing health condition.

Theanine safety at a glance

Theanine overall Use caution Generally well tolerated in healthy adults for short-term use, but long-term safety is not well studied.
Pregnancy Avoid Not enough safety data, so it is best to avoid supplements during pregnancy.
Breastfeeding Avoid Not enough safety data, so it is best to avoid supplements while breastfeeding.

Safety guidance is general; always confirm with your pharmacist or doctor for your situation.

Still wondering about combining Galantamine and Theanine? Ask Dr. Brian Staiger, PharmD, BCPS directly ›
How we checked

Why No Interaction Is Listed for Galantamine

Interactions in our licensed database are recorded against drug classes, not just single drug names. Galantamine is filed under 5 classifications — including acetylcholinesterase (ache) inhibitors, cholinergic drugs, cytochrome p450 2d6 (cyp2d6) substrates. Theanine has documented interactions with 3 drug classes — the most serious being antihypertensive drugs (moderate), cns depressants (minor) and serotonergic drugs (minor) — and none of Galantamine’s classifications are among them.

Classification data comes from our licensed Natural Medicines dataset. A medication can belong to classes beyond those recorded there, so this describes how the check was run — it is not a safety guarantee.

Keep it in perspective

Theanine Does Interact With Other Medications

Theanine has 172 moderate, 393 minor known drug interactions in our database — Galantamine isn’t one of them. If you take anything else, check it against the full list below.

Moderate 172 Minor 393 No known interaction 2,265 (incl. Galantamine)
Taking anything else?

Check Another of Your Medications Against Theanine

Covers the 2,830 medications we’ve checked against Theanine. Pick one to open its full report.

What to actually watch for

No Interaction Found — But Data Suggests Theanine and Galantamine May Share Several of the Same Side Effects

This is not an interaction. Neither one changes how your body handles the other, and nothing here says they react together. What our sources do show is that each has separately been linked to the effects below — so taking both can make those effects more likely to turn up, and harder to pin on one or the other if they do.

  • Drowsiness / Headache reported in 18.4% of FDA reports for Galantamine Additional detail

    Theanine

    “Orally, L-theanine may cause headaches. Patients have also reported drowsiness, increased duration of sleep, and increased dream activity after oral L-theanine use.

    A case of subtle facial tic starting within 4 days of taking L-theanine 400 mg daily has been reported for a pediatric patient. Although the tics reportedly ceased once theanine was discontinued, the child had exhibited tics in the past.”

    Theanine · Natural Medicines adverse-effect record, reported in insomnia.

    3 sources cited
    1. 36439. 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
    2. 96331. 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.
    3. 91744. 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-

    Galantamine

    Listed in the ADVERSE REACTIONS section of the FDA label for Galantamine, and in voluntary FDA adverse-event reports. Read the label on DailyMed ›

Effects for Galantamine come from the ADVERSE REACTIONS section of its FDA label; effects for Theanine come from the Natural Medicines adverse-effect record, quoted above. Where a percentage is shown, it is the share of 3,188 voluntary FDA FAERS reports for Galantamine that mention that effect — a reporting proportion, not an incidence rate and not evidence the drug caused it. Wording is matched across sources by our own clinical vocabulary, so treat this as a prompt to pay attention, not a diagnosis.

How to take them

Some Galantamine Products Have a Food Rule — Theanine Should Not Break It

At least one FDA label for a product containing Galantamine says to take it with food. If you take Theanine on an empty stomach out of habit, keep them separate — and take Galantamine with a meal where the label says to.

This may not be true of your version. Food instructions belong to the product, not the ingredient: two Galantamine products can carry different directions, and extended-release forms often differ from immediate-release ones. The label we read is quoted below — check the directions on your own box or bottle, or ask your pharmacist, for how to take the exact product you were given.

( 2.1 ) Take with food; ensure adequate fluid intake during treatment (2.1) Hepatic impairment: should not exceed 16 mg/day for moderate hepatic impairment; do not use in patients with severe hepatic impairment ( 2.2 ) Renal impairment: should not exceed 16 mg/day for creatinine clearance 9 to 59 mL/min; do not use in patients with creatinine clearance less than 9 mL/min.

From the Dosage and Administration section of the FDA label we read for Galantamine — where that label names a specific product, the instruction is that product's. Read the label on DailyMed ›

A food rule is not an interaction — it is about how much of the medicine you absorb. The directions that came with your own product, and your pharmacist, outrank anything on this page.

Overlapping uses

What Galantamine Is Prescribed For, and What Theanine Has Been Studied For

These two come up together because they touch the same health topic — not because they do the same job. Galantamine is a prescription medicine with approved uses on its FDA label. Theanine is a supplement: what follows is what researchers have looked at it for, and how strong that evidence is.

Galantamine is prescribed for: Galantamine — available as extended-release capsules, tablets, and an oral solution — is used to treat mild to moderate dementia caused by Alzheimer's disease. All supported formulations share this indication. It does not cure or slow the underlying disease, but it can help support cognitive function in people with early to moderate-stage Alzheimer's. Its benefits may lessen as the disease progresses and more brain cells are lost.

Theanine has been studied for:

  • Cognitive function Natural Medicines rates the evidence for Theanine: Possibly Effective Read what the research shows

    Theanine for cognitive function

    Oral L-theanine may improve some aspects of cognitive function. It is unclear if using L-theanine in conjunction with caffeine can enhance the effects of either ingredient.

Effectiveness ratings and the research summaries above are the verbatim record from the Natural Medicines database, which grades evidence from “Effective” down to “Insufficient Reliable Evidence To Rate”. A rating below the top of that scale means researchers have looked at it — not that it works, and never that it can stand in for a prescribed medicine. Do not stop or replace Galantamine on your own; if you are taking Theanine for the same health topic, tell your prescriber, especially if the medicine is being adjusted to a target.

From our Q&A

Questions About Theanine or Galantamine

These are real questions from readers, answered by the pharmacists at HelloPharmacist — written by a person, not generated from a database. Each one covers Theanine or Galantamine, not necessarily both, but if one is close to what you were about to ask it will usually go further than a database entry can:

Not quite your question? Ask our pharmacists directly — it is free, there is no account required, and answers usually come back within 24 hours.

Everything else you take

See Every Supplement That Interacts With Galantamine

This page covers Theanine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Galantamine page lists 170 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Grapefruit (major), St. John's Wort (major), 1,3-dmaa (moderate) and Acacia Rigidula (moderate).

By severity: 3 major · 126 moderate · 41 minor.

From our pharmacist’s overview on the Galantamine page

“Galantamine (Razadyne) treats Alzheimer's disease, so it is often a caregiver filling the pill organizer alongside memory supplements and morning juice. That pairing deserves genuine care, because three of the 170 supplement ingredients on file are rated major and two of them are everyday items.”

Reviewed by 2 · Jul 18, 2026

Open the Galantamine interaction page

One more smart check

Taking Theanine as Part of a Dietary Supplement Product? Check It for Interactions

We hold 3,298 real supplement products containing Theanine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Theanine. Even though Theanine itself has no known interaction with Galantamine, another ingredient on your label might. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Theanine and Galantamine Sit Against Everything Else

Out of every supplement and medication people look up on HelloPharmacist, here is where these two land this week — and which way each has been moving.

Supplement Theanine
Top 5%

#42 of 1,452 supplements looked up here in the last 7 days

29 days ago today
Medication Galantamine
Steady interest

#2,094 of 2,830 medications looked up here in the last 7 days

29 days ago today

Position among everything looked up on this site, not a measure of how commonly either one is used or how important it is. A supplement can climb this list because of a news story. It counts every request to the page, automated ones included, and nothing here identifies anyone.

Where does our data come from?
  • Source: the Natural Medicines (TRC Healthcare) clinical database — the evidence-graded professional reference for herb & supplement interactions.
  • Citation library: 103,510 references behind our interaction content, 65,311 of them resolved to verified PubMed/DOI sources. See every Theanine reference on this page ↓
  • Freshness: we automatically re-check this combination every week — this pair was last verified September 13, 2026. The Theanine and Galantamine records this page draws on were last updated July 10, 2026.
  • What “no known interaction” means: no documented interaction in the sources above — not a guarantee of safety. Supplements are studied far less than prescription drugs, so we say exactly what the evidence supports, and nothing more.
Data structure & sourcing designed and verified by .
Supplement

About Theanine

What is Theanine?

Theanine
  • Anxiety and stress
  • Relaxation and calm
  • Sleep support
  • Focus and cognitive function

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 help with relaxation and stress, but evidence for most uses is still limited. It appears generally well tolerated for short-term use, but check with your pharmacist or doctor before starting it.

Naturally found in tea leaves; supplements often use a synthesized or extracted form · Capsules, tablets, chewable tablets, powders, gummies, and tea

An interaction check asks whether these two react with each other — it does not ask whether Theanine is a good idea for someone in your situation. Here is what our Theanine record says about it on its own.

Theanine: dosing

There is no official standardized dose of theanine, and the right amount can vary by product and reason for use. The best approach is to follow the directions on the product label and not exceed them.Because supplements are not tightly regulated, doses and quality differ between brands.

From our Theanine monograph — the full record covers uses, side effects and every documented interaction.

Read the full Theanine monograph & all interactions
Medication

About Galantamine

What Is Galantamine Used For?

Brand names: Reminyl, Razadyne

Galantamine — available as extended-release capsules, tablets, and an oral solution — is used to treat mild to moderate dementia caused by Alzheimer's disease. All supported formulations share this indication.

It does not cure or slow the underlying disease, but it can help support cognitive function in people with early to moderate-stage Alzheimer's. Its benefits may lessen as the disease progresses and more brain cells are lost.

Most-Reported Side Effects for Galantamine

From FAERS, the FDA’s public side-effect reporting system (3,188 reports, all brands). Reports are voluntary and are not proof the drug caused the effect.

Fall 812 reports
Cognitive disorder 664 reports
Constipation 651 reports
Balance disorder 632 reports
Hypotension 631 reports
See full Galantamine drug information
Keep checking

Other Drugs & Theanine

Browse every other medication we’ve checked against Theanine — both the ones with a known interaction and the ones without. Select any drug for the full detail.

0Major
172Moderate
393Minor
2,264No known interaction
172 Moderate 393 Minor 2,264 No interaction
Moderate

172 interactions

Showing 60 of 172 moderate interactions — see all 172 on the Theanine page.

Minor

393 interactions

Showing 60 of 393 minor interactions — see all 393 on the Theanine page.

No interaction 2,264 drugs checked — show the list

We also checked Theanine against these medications and found no known interaction in our sources. Open any page to confirm.

Showing the 60 most looked-up of 2,264 medications checked with no known interaction — see the full Theanine list.

See the full Theanine interactions page
See every supplement checked against Galantamine, ranked by severity
Evidence & sources

Theanine References

The 6 references that drive our Theanine monograph and interaction data, from the evidence-graded Natural Medicines (TRC Healthcare) database. Citations with a link open the study on PubMed or the publisher’s site.

  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

Medication overviews come from MedlinePlus (NIH); supplement label data from the NIH Dietary Supplement Label Database. Content is written and reviewed by licensed HelloPharmacist pharmacists — see our data sources and editorial standards.

Pharmacist Counseling Corner

Taking Theanine and Galantamine Together: Common Questions

Is it safe to take Theanine with Galantamine?
We do not list a known interaction between Theanine and Galantamine. That does not guarantee the combination is risk-free, so confirm with your pharmacist or doctor — especially if you take other medications or have a health condition.
Do Theanine and Galantamine have any of the same side effects?
Yes — our sources link each of them separately to 2 of the same effects. That is not an interaction: neither changes how your body handles the other. It does mean that if one of those effects turns up, it can be harder to tell which one is behind it. They are listed on this page with the source behind each.
Should I take Theanine and Galantamine at the same time of day?
At least one FDA label for a product containing Galantamine says to take it with food. If you take Theanine on an empty stomach out of habit, keep them separate and take Galantamine with a meal where the label says to. Food instructions belong to the product rather than the ingredient — two Galantamine products can differ — so check the directions on your own box. This is about absorption, not an interaction.
Are Theanine and Galantamine used for the same thing?
They overlap in purpose, which usually means the real question is whether you need both rather than whether they are safe together. This page lists the shared uses and how strong the evidence is for Theanine in each. That is a conversation for your prescriber, especially if Galantamine is being adjusted to a target.
How was the Theanine and Galantamine combination checked?
Interactions in our licensed database are recorded against drug classes. Galantamine is filed under 5 classifications, and Theanine has documented interactions with 3 drug classes — none of Galantamine's classifications are among them. A medication can belong to classes beyond those recorded in our dataset, so this describes how the check was run rather than guaranteeing safety.
Does Theanine interact with any other medications?
Yes. Theanine has 565 documented drug interactions in our database — Galantamine is simply not one of them. If you take anything else, it is worth checking each one; they are all listed on this page.
Does Galantamine interact with any supplements?
Yes. Galantamine has documented interactions with 170 supplements in our database — Theanine is not one of them. The Galantamine interaction page linked on this page lists every one, ranked by severity.

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

Where next

Keep Exploring

Theanine monograph Uses, safety profile, and every drug interaction in one place Galantamine drug information The full plain-English guide to this medication Galantamine supplement interactions Every supplement checked against Galantamine, ranked by severity Supplement interaction checker Check any supplement or product against your medications Browse medications A–Z Every drug we’ve checked against herbs & supplements References The 6 citations behind this page Ask a pharmacist Free, personal answer from our licensed team

Still Have a Question About Galantamine and Theanine?

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This information is for education only and is not a substitute for professional medical advice. Always check with your pharmacist or doctor before starting, stopping, or combining supplements and medications.