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 Hydrochloride. 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 hydrochloride, an amino acid that your body uses to support immune function and tissue repair. The remaining ingredients—stearic acid, sorbitol, colloidal silicon dioxide, modified cellulose gum, and magnesium stearate—are inactive excipients that help form and stabilize the tablet.
Does it work?
Not established
L-lysine is possibly effective for herpes labialis (cold sores) based on available evidence. However, there is insufficient reliable evidence to rate its use for child growth, pressure ulcers, or diabetic foot ulcers, meaning the data we hold does not establish whether it works for those purposes.
How safe is it?
Well-documented data
At typical doses, lysine is generally well tolerated. High amounts may cause stomach upset (including abdominal pain, diarrhea, and indigestion), and long-term safety at high doses is not well studied.
One case report linked long-term oral lysine to kidney inflammation that progressed to chronic kidney disease, though this is rare. Lysine from food sources is fine during pregnancy, but supplement safety in pregnancy is not well studied—talk with your doctor before taking this supplement if you're pregnant.
There isn't enough reliable information on supplement use while breastfeeding, so caution is advised; discuss it with your doctor or pharmacist.
Meds to double-check
Minor interactions only
If you take a 5-HT4 agonist, confirm with your doctor or pharmacist before using this product—lysine may reduce its effects. No other medication interactions are documented for the ingredient we could check.
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 is a reasonable choice if you're looking for possibly effective support for cold sores and want a single-ingredient, generally well-tolerated option. If you take a 5-HT4 agonist (a gut-motility medication), check with your doctor or pharmacist before starting.
Talk with your own healthcare provider before using this supplement if you're pregnant, breastfeeding, or have kidney concerns.
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) | 021078001416 |
| Net contents | 50 Tablet(s) |
| Market status | On market |
| Date entered into DSLD | Aug 23, 2023 |
| DSLD ID | 295943 |
| 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), 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 Hydrochloride | 1 Gram(s) | -- |
Other ingredients: Stearic Acid, Sorbitol, Colloidal Silicon Dioxide, 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
Formula
Free form L-lysine
Formulation
L-lysine is an essential free-form amino acid which acts as a precursor for other amino acids, including l-carnitine (needed for 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.
Suitable for vegetarians.
Contains no yeast, dairy, egg, gluten, soy or wheat. Contains no sugar, starch, salt, preservatives, or artificial color, flavor or fragrance.
Suggested/Recommended/Usage/Directions
Suggested use: 1 tablet daily.
Precautions
Note: If you are pregnant, may become pregnant, or breast feeding, consult your health care professional before using this product.
Do not use if 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.
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 container50 Amounts shown are per serving.
L-Lysine Hydrochloride
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 Hydrochloride monograph & interactionsOther (inactive) ingredients: Stearic Acid, Sorbitol, Colloidal Silicon Dioxide, 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
L-Lysine 1,000 mg by Source Naturals has documented interactions through its single active ingredient, L-lysine hydrochloride.
The most serious documented interaction is a minor interaction with 5-HT4 agonists (a class of gut-motility medications). Animal research suggests lysine may act as a partial antagonist to these drugs, potentially reducing their effects.
Read the full breakdown — every affected drug type, severity by severity
Although we've identified this interaction category, the clinical significance remains unclear because human studies are limited. If you take a 5-HT4 agonist, it's worth confirming with your doctor or pharmacist before starting lysine.
Altogether, these interactions span 1 individual medication. Use the medication checker on this page to verify your exact prescriptions, and talk with your own healthcare provider or pharmacist before adding this supplement to your regimen.
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 Hydrochloride
TegaserodZelnorm
How Tegaserod interacts with L-Lysine 1,000 mg — through 1 ingredient. Tap an ingredient for the detail:
L-lysine Hydrochloride5-ht4 Agonists Minor
Interaction Summary
Theoretically, lysine may reduce the effects of 5-HT4 agonists.
Read the full L-lysine Hydrochloride + 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 Hydrochloride
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?
Does L-lysine really help with cold sores?
What side effects should I watch for?
Is it safe to take while breastfeeding?
Can I take this if I'm pregnant?
Why is there only one active ingredient?
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