Drug & supplement interaction

Threonine + Memantine

Memantine brand name: Ebixa.

Major Interaction
Medically reviewed by · Updated September 2026
The bottom line Major

Threonine has a major interaction with Memantine. Theoretically, threonine might decrease the effects of NMDA antagonists.

Read the full interaction report
SeverityMajor
LikelihoodLikely
EvidenceB
What do Severity, Likelihood & Evidence mean?
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Interaction report

Threonine and Memantine

Here is the interaction we found between these two, with the evidence behind it.

Major

NMDA ANTAGONISTS

Why this applies to Memantine

Memantine falls under NMDA ANTAGONISTS — the group Threonine interacts with.

Theoretically, threonine might decrease the effects of NMDA antagonists.
Threonine increases central nervous system (CNS) glycine levels. Glycine seems to bind a site on NMDA receptors and enhance the activity of the receptors.
Severity Major Likelihood Likely Evidence B

Well-controlled human studies have demonstrated the likely existence of this interaction.

Dr. Brian Staiger, PharmD, BCPS
Dr. Brian Staiger explains PharmD, Clinical Pharmacist

Here's the idea behind pairing threonine with memantine (Ebixa). Memantine works by calming down overactive NMDA receptors in the brain. Threonine can raise levels of glycine, and glycine actually does the opposite, it nudges those same NMDA receptors to be more active. So in theory, threonine could push against memantine and make it work a little less well for memory and thinking.

I want to be honest about the strength of this. It's largely theoretical and based on lower-quality evidence, so we don't have solid proof it causes real problems in people. The threonine you get from a normal diet is very unlikely to matter. Concentrated supplements are the bigger question mark. Before adding a threonine supplement, please run it by your pharmacist or doctor first.

Contact Dr. Brian directly if you have additional questions on this interaction
References
  1. Tandan R, Bromberg MB, Forshew D, et al. A controlled trial of amino acid therapy in amyotrophic lateral sclerosis: I. Clinical, functional, and maximum isometric torque data. Neurology 1996;47:1220-6. PubMed
  2. Blin O, Pouget J, Aubrespy G, et al. A double-blind placebo controlled trial of L-threonine in amyotrophic lateral sclerosis. J Neurol 1992;239:79-81.
  3. Roufs JB. L-threonine as a symptomatic treatment for amyotrophic lateral sclerosis (ALS). Med Hypotheses 1991;34:20-3. PubMed

What These Ratings Mean

Every interaction above is graded three ways — here’s the key to each label.

Severity how clinically significant the interaction is
Major

Clinically significant. Avoid the combination, or use only under close professional supervision.

Moderate

Usually worth avoiding or managing — may need monitoring, a dose change, or timing apart.

Minor

Generally not serious. Be aware of it and mention it to your pharmacist.

Likelihood how strong the evidence is that the interaction actually happens in people
  • LikelyWell-controlled human studies have demonstrated the likely existence of this interaction.
  • ProbableInteraction has not been documented in well-controlled studies, however, the interaction has been demonstrated in some small human studies or in controlled animal studies in conjunction with multiple case reports.
  • PossibleInteraction has been documented in animal or in lab research, or the interaction has been documented in humans but is limited to case reports or conflicting clinical research exists.
  • UnlikelyInteraction has been demonstrated in animal or in lab research but has been shown not to occur in humans.
Evidence the quality of the studies behind the rating (graded A–D)
  • AHigh-quality meta-analysis (quantitative systematic review).
  • BCase-control study.
  • CConsensus.
  • DAnecdotal evidence.

These ratings are for information only. Never start, stop, or otherwise change your therapy before speaking with your provider.

Keep it in perspective

Threonine Also Interacts With Other Medications

Threonine has 2 major, known drug interactions in our database — the Memantine one above is one of them. If you take anything else, check it against the full list below.

Major 2 No known interaction 2,828 (incl. Memantine)
Taking anything else?

Check Another of Your Medications Against Threonine

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

Everything else you take

See Every Supplement That Interacts With Memantine

This page covers Threonine only. If you take other supplements — a multivitamin, a sleep aid, something for joints — the Memantine page lists 18 supplements it has a documented interaction with, worst first, each one explained.

The most serious there right now: Activated Charcoal (major), Coffee Charcoal (moderate), European Mandrake (moderate), Glucomannan (moderate) and Guar Gum (moderate).

By severity: 2 major · 7 moderate · 9 minor.

Open the Memantine interaction page

One more smart check

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

We hold 1,803 real supplement products containing Threonine, each one broken down to its full ingredient list — and combination products often carry several ingredients besides Threonine. Your product may carry other ingredients that interact with Memantine too, on top of Threonine — and those would not show on this page. Find your product and we’ll check every ingredient on its label:

How much people look this up

Where Threonine and Memantine 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 Threonine
Top 10%

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

29 days ago today
Medication Memantine
Steady interest

#1,620 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.

Supplement

About Threonine

What is Threonine?

  • General amino acid/protein support
  • Muscle and tissue health
  • Immune support
  • Nervous system support (as a precursor)
  • Liver health (proposed)

Threonine is an essential amino acid your body needs but cannot make, so you must get it from food or supplements. Most people get plenty from a normal diet, and high-quality evidence for taking it as a separate supplement is limited. If you are considering threonine supplements, talk with your pharmacist or doctor first.

Read the full Threonine monograph & all interactions
Medication

About Memantine

What Is Memantine Used For?

Brand name: Ebixa

Memantine treats moderate to severe dementia of the Alzheimer's type. It is available as tablets, extended-release capsules, and an oral solution — all approved for this same use.

It does not cure Alzheimer's disease and is not shown to prevent or slow the underlying loss of brain cells. It is used to help manage symptoms of moderate to severe disease.

See full Memantine drug information
Keep checking

Other Drugs & Threonine

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

2Major
0Moderate
0Minor
2,827No known interaction
2 Major 2,827 No interaction
Major

2 interactions

No interaction 2,827 drugs checked — show the list

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

Showing the 60 most looked-up of 2,827 medications checked with no known interaction — see the full Threonine list.

See the full Threonine interactions page
See every supplement checked against Memantine, ranked by severity
Sources

Sources & How We Checked

Interaction details are evidence-graded and sourced from the Natural Medicines database. The medication overview comes from MedlinePlus.

Content is written and reviewed by licensed HelloPharmacist pharmacists. See our data sources and editorial standards for how this information is built and checked.

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

Keep exploring
Threonine monograph › Uses, safety, and every drug interaction in one place Memantine supplement interactions › Every supplement checked against Memantine, ranked by severity Memantine drug information › The full plain-English guide to this medication Supplement interaction checker › Check any supplement or product against your medications Browse medications A–Z › Every drug we've checked against herbs & supplements Ask a pharmacist › Free, personal answer from our licensed team
Pharmacist Counseling Corner

Taking Threonine and Memantine Together: Common Questions

Can you take Threonine with Memantine?
This is rated a major interaction, so the combination is best avoided unless your doctor or pharmacist has specifically told you otherwise. Read the full details on this page and confirm with your pharmacist before combining them.
How serious is the Threonine and Memantine interaction?
We rate it Major. This is a clinically significant combination that is generally best avoided, or used only under the direct supervision of your physician or pharmacist.

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

Still Have a Question About Memantine and Threonine?

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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.