L-Lysine 1000 mg Ingredients & Drug Interactions
What is this page for?
First and foremost: checking L-Lysine 1000 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-Lysine 1000 mg is a dietary supplement by Sundown Naturals with 1 active ingredient. Its ingredients are commonly taken for cold sores (herpes labialis), genital herpes outbreaks, supporting protein and collagen formation.Based on those ingredients, 1 medication has a known interaction with it, the most serious rated minor. The ingredients most likely to interact are L-Lysine. Use the checker below to test your specific medication, or read the full HelloPharmacist Interaction Report.
Check Your Meds Against L-Lysine 1000 mg by Sundown Naturals
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine 1000 mg by Sundown Naturals — 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-Lysine 1000 mg by Sundown Naturals
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-lysine, an amino acid (a building block of protein) at 1000 mg per serving. The inactive ingredients are vegetable cellulose (the capsule material) and minor other ingredients.
Does it work?
Moderate evidence
L-lysine is possibly effective for cold sores (herpes labialis) — the research supports its use there. For child growth, pressure ulcers, and diabetic foot ulcers, there isn't enough reliable evidence yet to say whether it works.
How safe is it?
Well-documented data
L-lysine from food is safe in normal amounts. As a supplement, it's generally well tolerated at typical doses, though high amounts may cause stomach upset, diarrhea, or abdominal pain.
Long-term safety at high doses isn't well studied. In pregnancy, lysine supplement safety isn't well studied, so talk with your doctor before taking it — that's different from lysine in food, which is fine.
For breastfeeding, there isn't enough reliable information, so caution is advised; check with your doctor or pharmacist for guidance tailored to your situation.
Meds to double-check
Minor interactions only
Check with your doctor or pharmacist if you take a 5-HT4 agonist (a medication that works on serotonin receptor 4, used for certain digestive issues) — lysine may reduce how well it works.
The bottom line
Scorecard at a glanceFully disclosed formula with some supporting evidence behind its ingredients' uses. Only minor medication interactions are documented, and safety information is well characterized.
L-lysine may help with cold sores if you want to try it. If you take a 5-HT4 agonist for GI issues, run that by your doctor or pharmacist first.
Pregnant or breastfeeding? Talk it over with your healthcare provider before starting — the data on supplement use isn't complete enough to say it's clear either way.
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 Feb 23, 2012.
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-Lysine 1000 mg, straight from the product label.
| Brand | Sundown Naturals |
|---|---|
| Barcode (UPC) | 030768005931 |
| Net contents | 100 Caplet(s) |
| Market status | On market |
| Date entered into DSLD | Feb 23, 2012 |
| DSLD ID | 5792 |
| Product type | Amino Acid/protein |
| Supplement form | Other (e.g. Tea Bag) |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Vegetarian, Adult (18 - 50 Years), Gluten Free, Sugar 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-Lysine 1000 mg by Sundown Naturals, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Lysine | 1000 mg | -- |
Other ingredients: Vegetable Cellulose, Contains <2% of
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.
FDA Statement of Identity
DIETARY SUPPLEMENT
Suggested/Recommended/Usage/Directions
DIRECTIONS: FOR ADULTS, TAKE ONE (1) CAPLET DAILY, PREFERABLY WITH A MEAL. As a reminder, discuss the supplements and medications you take with your health care providers.
Precautions
KEEP OUT OF REACH OF CHILDREN.
WARNING: If you are pregnant, nursing or taking any medications, consult your doctor before use.
Discontinue use and consult your doctor if any adverse reactions occur.
TAMPER RESISTANT: DO NOT USE IF SEAL UNDER CAP IS BROKEN OR MISSING.
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.
Storage
STORE IN A DRY PLACE AND AVOID EXCESSIVE HEAT.
Brand IP Statement(s)
2010
General Statements
COATED FOR EASY SWALLOWING
Essential Amino Acid
Promotes the Production of Collagen & Healthy Skin*
Smart Facts Since it cannot be made by the body, Lysine is an indispensable amino acid.* Amino acids perform a variety of functions and form the basis for protein.* Lysine is also used for the production of collagen and tissue maintenance.*
General
Prod. No. 45097 08F B6011 KAZ
Formulation
VEGETARIAN FORMULA
No Artificial Flavor or Sweetener, No Preservatives, No Sugar, No Starch, No Milk, No Lactose, No Soy, No Gluten, No Wheat, No Yeast, No Fish.
Sodium Free.
Seals/Symbols
GUARANTEED QUALITY LABORATORY TESTED
PLEASE RECYCLE
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine 1000 mg by Sundown Naturals 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-Lysine 1000 mg by Sundown Naturals
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Caplet(s) Dosage formOther (e.g. Tea Bag) Amounts shown are per serving.
L-Lysine
Interacts with1 drug
Lysine is an essential amino acid your body cannot make on its own, so it must come from food or supplements. People most often take extra lysine to t...
L-Lysine monograph & interactionsOther (inactive) ingredients: Vegetable Cellulose, Contains <2% of. These complete the product’s ingredient list but are not active constituents.
L-Lysine 1000 mg by Sundown Naturals Drug Interactions
HelloPharmacist Interaction Report
L-Lysine 1000 mg by Sundown Naturals has documented interactions with one medication type.
The main concern is with 5-HT4 agonists (drugs that work on a specific serotonin receptor to treat certain GI problems). Animal research suggests lysine may block the effects of these medications, potentially making them less effective.
Read the full breakdown — every affected drug type, severity by severity
Although the evidence is from animal studies rather than humans, if you take a 5-HT4 agonist, it's worth a conversation with your doctor or pharmacist before starting lysine. Altogether, these interactions span 1 individual medication.
You can search for your exact drug below to see if it's one of them.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Lysine 1000 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-Lysine 1000 mg interact with 1 drug. Click any drug to see the details.
1 of the 1 ingredient in L-Lysine 1000 mg interact with drugs. Each result below shows which ingredient is responsible. L-Lysine
TegaserodZelnorm
How Tegaserod interacts with L-Lysine 1000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-lysine5-ht4 Agonists Minor
Interaction Summary
Theoretically, lysine may reduce the effects of 5-HT4 agonists.
Read the full L-lysine + Tegaserod interactionEach ingredient & the kinds of drugs it affects
For each ingredient in L-Lysine 1000 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-Lysine
5-Ht4 Agonists
Theoretically, lysine may reduce the effects of 5-HT4 agonists.
Animal research suggests that L-lysine is a partial serotonin receptor 4 (5-HT4) antagonist and inhibits diarrhea induced by the 5-HT4 agonist, 5-hydroxytryptophane.
Brand information
Manufacturer and brand details for L-Lysine 1000 mg, from the product label.
L-Lysine 1000 mg by Sundown Naturals: Common Questions
Does L-Lysine 1000 mg by Sundown Naturals interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Will L-lysine help my cold sores?
What side effects should I watch for?
Can I take this if I'm pregnant?
Is it safe while breastfeeding?
Why is there only one ingredient?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Lysine 1000 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-Lysine 1000 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-Lysine 1000 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 7 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.
Lysine 7 references
- Thein DJ, Hurt WC. Lysine as a prophylactic agent in the treatment of recurrent herpes simplex labialis. Oral Surg Oral Med Oral Pathol 1984;58:659-66. PubMed
- McCune MA, Perry HO, Muller SA, O'Fallon WM. Treatment of recurrent herpes simplex infections with L-lysine monohydrochloride. Cutis 1984;34:366-73.
- DiGiovanna JJ, Blank H. Failure of lysine in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Arch Dermatol 1984;120:48-51. DOI
- Milman N, Scheibel J, Jessen O. Lysine prophylaxis in recurrent herpes simplex labialis: a double-blind, controlled crossover study. Acta Derm Venereol 1980;60:85-7.
- Griffith RS, Walsh DE, Myrmel KH, et al. Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Dermatologica 1987;175:183-90. DOI
- Lo JC, Chertow GM, Rennke H, Seifter JL. Fanconi's syndrome and tubulointerstitial nephritis in association with L-lysine ingestion. Am J Kidney Dis 1996;28:614-7. PubMed
- Smriga M, Torii K. L-Lysine acts like a partial serotonin receptor 4 antagonist and inhibits serotonin-mediated intestinal pathologies and anxiety in rats. Proc Natl Acad Sci U S A. 2003 Dec 23;100(26):15370-5.
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