Major interaction on record — check this product against your medications before combining. Check your meds →
Dietary supplement

L-Threonine Ingredients & Drug Interactions

by BulkSupplements.com

L-Threonine label
See full label image
Powder Category: Amino Acid/protein
Most serious interaction: Major
Clinical methodology reviewed by · Updated Sep 9, 2026 · Label data from the NIH DSLD
What is this page for?

First and foremost: checking L-Threonine 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: Major

L-Threonine is a dietary supplement by BulkSupplements.com with 1 active ingredient. Its ingredients are commonly taken for general amino acid/protein support, muscle and tissue health, immune support.Based on those ingredients, 3 medications have a known interaction with it, the most serious rated major. The ingredients most likely to interact are L-Threonine. 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-Threonine by BulkSupplements.com

Ask about any prescription or over-the-counter medication and we check it for interactions with L-Threonine by BulkSupplements.com — and tell you which ingredient is responsible.

Pharmacist-reviewed data Checks every ingredient Answer in seconds
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HelloPharmacist Scorecard of L-Threonine by BulkSupplements.com

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.

This product contains one active ingredient: L-threonine, an amino acid your body uses to build protein and support various metabolic functions. The powder form allows flexible dosing.

There are no inactive ingredients listed.

Does it work?

Couldn't assess
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 assessable

This is a single-ingredient Threonine product and its label doesn't state a use — see Threonine's own graded uses on its monograph.

Why this rating?
  • We looked at the product name, claims, and label statements and couldn't find a stated purpose to grade.

The evidence for L-threonine is mixed and limited. For amyotrophic lateral sclerosis (ALS), it's rated possibly ineffective.

For multiple sclerosis, familial spastic paraparesis, and spasticity, there isn't enough reliable evidence to rate whether it works. The data we hold doesn't establish clear effectiveness for other uses.

The evidence, ingredient by ingredient Threonine

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.

Threonine from food is well tolerated, but supplement safety at higher doses hasn't been well studied. Headache has been reported by some people taking threonine supplements, and a small number have experienced mild gastrointestinal upset including diarrhea, gas, or constipation.

Because supplement use during pregnancy and breastfeeding hasn't been well studied, the safety data advises against it unless your doctor or midwife advises otherwise.

Side effects, ingredient by ingredient Threonine

Meds to double-check

Major interaction found
Known Interaction Concern · database check
Major identified

At least one ingredient has a documented Major-severity interaction. Check your medications for a personalized result.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Threonine.
  • The most serious interaction on file is rated Major.
  • For scale: 3 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.

If you take an NMDA antagonist, double-check with your doctor or pharmacist before starting this product; threonine could reduce its effectiveness. No other medication interactions are documented for the ingredient we checked.

Check your own medication Run your meds through the checker above

The bottom line

Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Major medication interactions have been identified, and safety information is well characterized.

L-Threonine is a single amino acid supplement with limited evidence for its claimed uses. If you're taking an NMDA antagonist, check with your doctor or pharmacist first—this product may interfere with how it works.

Anyone considering it during pregnancy or breastfeeding should talk it over with their healthcare provider, since the safety data at supplement doses is incomplete.

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 Oct 22, 2021.

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-Threonine, straight from the product label.

Brand BulkSupplements.com
Barcode (UPC) X000IOD1Y1
Net contents 500 Gram(s); 17.6 oz
Market status On market
Date entered into DSLD Oct 22, 2021
DSLD ID 254818
Product type Amino Acid/protein
Supplement form Powder
Dietary claims / uses All Other, Structure/Function
Intended target group(s) Adult (18 - 50 Years), 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 L-Threonine by BulkSupplements.com, 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:
2000 mg
Maximum serving Sizes:
2000 mg
Servings per container
250
UPC/BARCODE
X000IOD1Y1
IngredientAmount% DV
L-Threonine2000 mg--

Other ingredients: None

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

Clean & pure bulk supplements

FDA Disclaimer Statement

Warning: This product is not intended to diagnose, treat, cure, or prevent any disease.

Precautions

Always consult a physician before taking any dietary supplement.

Keep out of reach of children.

Formulation

Free of: Added sugar, soy, dairy, yeast, gluten, additives

Suggested/Recommended/Usage/Directions

Suggested Use: As a dietary supplement, take 2000 mg (about 3/4 tsp) once daily, or as directed by a physician.

Storage

Store in a dry, cool place

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

See for yourself

L-Threonine by BulkSupplements.com label

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

L-Threonine 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-Threonine by BulkSupplements.com

This is the 1 active ingredient this product is made of. Select it to open its full monograph.

Serving size2000 mg Dosage formPowder Servings per container250 Amounts shown are per serving.

L-Threonine

Interacts with
3 drugs
2000 mg per serving

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 norma...

L-Threonine monograph & interactions

Other (inactive) ingredients: None. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Threonine by BulkSupplements.com Drug Interactions

Want to check YOUR meds against L-Threonine?

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
3Drugs
3 Major

Ingredients driving the most interactions

L-Threonine 3

Individual Drug Interactions

The ingredients in L-Threonine interact with 3 drugs. Click any drug to see the details.

1 of the 1 ingredient in L-Threonine interact with drugs. Each result below shows which ingredient is responsible. L-Threonine

Each ingredient & the kinds of drugs it affects

For each ingredient in L-Threonine 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-Threonine1 drug type · 3 drugs

Nmda Antagonists

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.

Likelihood Likely Evidence B
L-Threonine full monograph & interactions
The maker

Brand information

Manufacturer and brand details for L-Threonine, from the product label.

BulkSupplements.com

See all BulkSupplements.com products
Name
BulkSupplements.com
Street Address
7511 Eastgate Rd
City
Henderson
State
NV
ZipCode
89011
Web Address
BulkSupplements.com
Pharmacist Counseling Corner

L-Threonine by BulkSupplements.com: Common Questions

Does L-Threonine by BulkSupplements.com interact with any medications?
Yes. Based on its ingredients, L-Threonine has a known interaction with 3 medications, including 3 rated major. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
L-Threonine 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.
What is L-threonine, and what does it do in the body?
L-threonine is an amino acid—one of the building blocks your body uses to make protein and support metabolism. This supplement provides a concentrated dose beyond what you'd get from a typical diet.
Does L-threonine help with multiple sclerosis or spasticity?
There isn't enough reliable evidence to say whether it works for those conditions. For ALS, it's been rated possibly ineffective. The data we hold doesn't support a clear benefit for these uses.
Is it safe to take L-threonine if I'm pregnant or breastfeeding?
Supplement use during pregnancy and breastfeeding hasn't been well studied, so the safety data advises against it unless your doctor specifically recommends it. Talk it over with your healthcare provider before taking it.
What side effects might I experience?
Headache has been reported by some users. Others have had mild stomach upset, including diarrhea, gas, or constipation. These appear to be uncommon, but they're the main effects documented in people taking threonine.
Is L-threonine safe at supplement doses?
While threonine from food is safe, safety at the higher doses found in supplements hasn't been well studied. This is worth keeping in mind if you're considering taking it long-term.

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

Not sure if L-Threonine is safe with your meds?

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Ask a pharmacist

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-Threonine label
Go deeper

The Full Monographs Behind L-Threonine’s Ingredients

Every ingredient we hold a full HelloPharmacist monograph for — uses, evidence, safety, and the complete interaction list.

Herb & supplement monograph

Threonine

Interacts with 3 drugs

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 ta...

Read the full Threonine monograph →
Sources

Sources & How We Checked

L-Threonine'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 4 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.

Threonine 4 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. Lee A, Patterson V. A double blind study of L-threonine in patients with spinal spasticity. Acta Neurol Scand 1993;88:334-8. PubMed
  3. 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.
  4. Roufs JB. L-threonine as a symptomatic treatment for amyotrophic lateral sclerosis (ALS). Med Hypotheses 1991;34:20-3. PubMed

See these in context on the Threonine 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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