L-Lysine 1000 mg Ingredients & Drug Interactions
by KAL
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 KAL 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 KAL
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine 1000 mg by KAL — 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 KAL
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 at 1,000 mg per tablet. Lysine is an amino acid — one of the building blocks your body uses to make protein.
It's also wrapped in inactive ingredients including cellulose, stearic acid, magnesium stearate, and titanium dioxide, which help form and preserve the tablet.
Does it work?
Couldn't assess
The evidence we hold shows lysine is possibly effective for herpes labialis (cold sores). For other uses — child growth, pressure ulcers, and diabetic foot ulcers — the evidence isn't established in our data, so we can't rate how well it works for those.
How safe is it?
Well-documented data
Lysine is generally well tolerated at normal doses, though high amounts may cause stomach upset (abdominal pain, diarrhea, indigestion). Long-term safety from supplements hasn't been thoroughly studied.
There's one rare case report of someone developing kidney inflammation linked to lysine use, but this is not common. Lysine from food is safe in pregnancy, but supplement safety during pregnancy and breastfeeding hasn't been well studied — talk with your doctor or pharmacist before taking it if you're pregnant or nursing.
Meds to double-check
Minor interactions only
Check with your doctor or pharmacist before taking this product if you use a 5-HT4 agonist, as lysine may reduce how well it works. Although this is the only interaction documented in our data, it's worth confirming your exact medications before you start.
The bottom line
Scorecard at a glanceFully disclosed formula with no assessable stated purpose. Only minor medication interactions are documented, and safety information is well characterized.
L-lysine may be worth considering if you're looking for something possibly effective for cold sores. If you take a 5-HT4 agonist medication, check with your doctor or pharmacist first.
Stomach upset is the main side effect to watch for at higher doses, and long-term safety data is limited. Discuss it with your own healthcare provider before starting, especially if you're pregnant, breastfeeding, or on any medications.
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
General information
Key facts about L-Lysine 1000 mg, straight from the product label.
| Brand | KAL |
|---|---|
| Barcode (UPC) | 021245805144 |
| Net contents | 100 Tablet(s) |
| Market status | On market |
| Date entered into DSLD | Oct 22, 2021 |
| DSLD ID | 254599 |
| Product type | Amino Acid/protein |
| Supplement form | Tablet Or Pill |
| Dietary claims / uses | All Other, Structure/Function |
| Intended target group(s) | Vegetarian, Adult (18 - 50 Years) |
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 KAL, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Calories | 5 Calorie(s) | -- |
| L-Lysine | 1000 mg | -- |
Other ingredients: Cellulose, Stearic Acid, Magnesium Stearate, Titanium Dioxide
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.
General Statements
KAL Innovative Quality Since 1932
Clear quality
FDA Statement of Identity
Dietary Supplement
Suggested/Recommended/Usage/Directions
1 Daily
Directions: Use only as directed. Take 1 tablet daily with a meal or glass of water.
Formulation
Essential protein component Free form
Discussion: High potency vegetarian formula.
KAL guarantees that no ingredients other than those listed on this label have been added to this product. ActivTab technology guarantees tablet disintegration within 30 minutes according to USP standards.
Precautions
Warning: Do not use if safety seal is broken or missing.
Keep out of reach of children.
Keep your licensed health care practitioner informed when using this product.
Storage
Store in a cool, dry place.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine 1000 mg by KAL 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 KAL
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Tablet(s) Dosage formTablet Or Pill Servings per container100 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: Cellulose, Stearic Acid, Magnesium Stearate, Titanium Dioxide. These complete the product’s ingredient list but are not active constituents.
L-Lysine 1000 mg by KAL Drug Interactions
HelloPharmacist Interaction Report
KAL's L-Lysine 1000 mg through its lysine content may reduce the effects of 5-HT4 agonists (a class of medications that work on serotonin receptors in the gut).
The interaction is rated Minor. Animal research suggests lysine acts as a partial blocker of the 5-HT4 receptor and can inhibit the diarrhea-causing effects of 5-HT4 agonists — which means if you're taking one of these drugs, lysine could theoretically blunt how well it works.
Read the full breakdown — every affected drug type, severity by severity
Although this is the only interaction documented in our data, the full list of 5-HT4 agonists is limited. If you take any medication in this class, it's worth confirming with your doctor or pharmacist before starting lysine that the interaction won't matter for your situation.
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.
KAL
See all KAL products- Name
- KAL
- City
- Park City
- State
- UT
- ZipCode
- 84060
- Phone Number
- (800) 365-5966
- Web Address
- www.kalvitamins.com
L-Lysine 1000 mg by KAL: Common Questions
Does L-Lysine 1000 mg by KAL interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Does L-lysine actually help with cold sores?
Can I take this while I'm pregnant?
What about while breastfeeding?
What side effects might I see?
Can I take this if I'm on medications?
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