L-Lysine 1,000 mg Ingredients & Drug Interactions
by Source Naturals
What is this page for?
First and foremost: checking L-Lysine 1,000 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 1,000 mg is a dietary supplement by Source 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 1,000 mg by Source Naturals
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine 1,000 mg by Source 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 1,000 mg by Source 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 your body uses to build and repair proteins. The tablet also includes inactive ingredients—stearic acid, sorbitol, silica, modified cellulose gum, and magnesium stearate—that help form and preserve the pill.
Does it work?
Not established
L-lysine is possibly effective for cold sores (herpes labialis). The evidence for other uses—child growth, pressure ulcers, and diabetic foot ulcers—is not strong enough yet to say whether it works.
If you're considering it for a cold sore, talk with your doctor about whether it fits your situation.
How safe is it?
Well-documented data
L-lysine from food is safe. When taken as a supplement at typical doses, it's generally well tolerated, though some people report stomach upset, diarrhea, abdominal pain, or indigestion.
High amounts may cause stomach upset, and long-term safety from supplements hasn't been thoroughly studied. There is one rare case report linking long-term oral lysine to a serious kidney problem, though this is not common.
Supplement safety during pregnancy has not been well studied—the facts show lysine from food is fine, but check with your doctor before taking a supplement. There isn't enough reliable information on supplement use while breastfeeding either, so caution is advised; talk it over with your doctor or pharmacist.
Meds to double-check
Minor interactions only
If you take a 5-HT4 agonist (a drug that works on serotonin receptor 4), check with your doctor or pharmacist before starting L-lysine, as it may reduce how well the drug works.
The bottom line
Scorecard at a glanceFully disclosed formula with no established evidence rating for its marketed use. Only minor medication interactions are documented, and safety information is well characterized.
L-lysine may help with cold sores if you're looking for a possibly effective option. It's generally well tolerated at normal doses, though some people experience stomach upset or diarrhea.
If you take a 5-HT4 agonist, confirm with your doctor or pharmacist first. Pregnant or breastfeeding?
Chat with your own healthcare provider about whether this supplement is right for you.
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 Aug 23, 2023.
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 1,000 mg, straight from the product label.
| Brand | Source Naturals |
|---|---|
| Barcode (UPC) | 021078026808 |
| Net contents | 200 Tablet(s) |
| Market status | On market |
| Date entered into DSLD | Aug 23, 2023 |
| DSLD ID | 295944 |
| Product type | Amino Acid/protein |
| Supplement form | Tablet Or Pill |
| Dietary claims / uses | Nutrient, All Other, Structure/Function |
| Intended target group(s) | Vegetarian, Adult (18 - 50 Years), Gluten Free, Dairy 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 1,000 mg by Source Naturals, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| Calories | 5 Calorie(s) | -- |
| L-Lysine | 1 Gram(s) | -- |
Other ingredients: Stearic Acid, Sorbitol, Silica, modified Cellulose Gum, Magnesium Stearate
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
Formulation
Free form
Suitable for vegetarians.
Contains no yeast, dairy, egg, gluten, soy or wheat. Contains no sugar, starch, preservatives, or artificial color, flavor or fragrance.
Formula
L-Lysine is an essential free-form amino acid which acts as a precursor for other amino acids, including L-carnitine (needed for fat metabolism). L-Lysine is crucial for the formation of collagen, a major part of the body’s connective tissues. L-Lysine also contributes to energy production when converted to acetyl coenzyme A, one of the principal fuels for the Krebs cycle.
Suggested/Recommended/Usage/Directions
Suggested Use: 1 tablet daily.
Precautions
Note: If you are pregnant, may become pregnant, or breastfeeding, consult your health care professional before using this product.
Do not use if either tamper-evident seal is broken or missing.
Keep out of the reach of children.
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.
Brand IP Statement(s)
Copyright SOURCE NATURALS, INC.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine 1,000 mg by Source 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 1,000 mg by Source Naturals
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 container200 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: Stearic Acid, Sorbitol, Silica, Modified Cellulose Gum, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.
L-Lysine 1,000 mg by Source Naturals Drug Interactions
HelloPharmacist Interaction Report
Source Naturals L-Lysine 1,000 mg interacts with one medication type through its lysine content.
The interaction is minor: lysine may theoretically reduce how well 5-HT4 agonists (drugs that work on a specific serotonin receptor) perform. Animal research suggests lysine blocks this receptor and can inhibit diarrhea triggered by 5-HT4 agonists, though human evidence is limited.
Read the full breakdown — every affected drug type, severity by severity
Although this is a Minor interaction, if you take a 5-HT4 agonist, check with your doctor or pharmacist before starting lysine to make sure it won't affect your treatment. Altogether, these interactions span 1 individual medication.
Use the medication checker on this page to search for your exact drugs, or talk with your own pharmacist to be sure.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Lysine 1,000 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 1,000 mg interact with 1 drug. Click any drug to see the details.
1 of the 1 ingredient in L-Lysine 1,000 mg interact with drugs. Each result below shows which ingredient is responsible. L-Lysine
TegaserodZelnorm
How Tegaserod interacts with L-Lysine 1,000 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 1,000 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 1,000 mg, from the product label.
Source Naturals
- Name
- Source Naturals, Inc.
- Street Address
- P. O. Box 2118
- City
- Santa Cruz
- State
- CA
- ZipCode
- 95062
- Web Address
- www.sourcenaturals.com
L-Lysine 1,000 mg by Source Naturals: Common Questions
Does L-Lysine 1,000 mg by Source Naturals interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Can I take L-lysine while pregnant or breastfeeding?
What does L-lysine actually do?
Are there any side effects?
Does this product contain fillers?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Lysine 1,000 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 1,000 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 1,000 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