L-Lysine 500 mg Ingredients & Drug Interactions
What is this page for?
First and foremost: checking L-Lysine 500 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 500 mg is a dietary supplement by Nature's Harmony 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 500 mg by Nature's Harmony
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine 500 mg by Nature's Harmony — 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 500 mg by Nature's Harmony
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 tissue. At 500 mg per capsule, you're getting a concentrated dose in a straightforward formula.
The capsule also contains inactive ingredients—calcium silicate, silicon dioxide, magnesium stearate, and gelatin—which help hold the supplement together and protect it until it reaches your digestive system.
Does it work?
Moderate evidence
L-lysine is possibly effective for herpes labialis (cold sores), meaning there's some evidence it may help, though it's not conclusive. For other uses listed here—child growth, pressure ulcers, and diabetic foot ulcers—the evidence isn't established in our data.
If you're considering it for a cold sore, talk with your doctor or pharmacist about whether the evidence fits your situation.
How safe is it?
Well-documented data
L-lysine is generally well tolerated at typical doses. Some people report stomach upset, abdominal pain, diarrhea, or indigestion when taking it orally.
High amounts may cause these side effects more readily, and long-term safety at high doses hasn't been well studied. There's one rare case report of kidney inflammation linked to oral lysine use, though this is uncommon.
For pregnancy, the safety data on lysine supplements isn't well studied—food sources are fine, but supplement use needs discussion with your doctor first. For breastfeeding, there isn't enough reliable information to know either way, so caution is advised and you should check with your doctor or pharmacist.
Meds to double-check
Minor interactions only
If you take a 5-HT4 agonist, double-check with your doctor or pharmacist before adding this product—lysine may reduce how well these medications work. For the ingredients we could check, that's the only documented interaction.
The bottom line
Scorecard at a glanceFully disclosed formula with some supporting evidence for its stated purpose. Only minor medication interactions are documented, and safety information is well characterized.
L-lysine is generally well tolerated and possibly effective for cold sores if the evidence matches what you're after. Watch out for stomach upset, especially at higher doses.
If you take a 5-HT4 agonist, mention this to your doctor or pharmacist before starting. Anyone pregnant, breastfeeding, or dealing with kidney concerns should talk it over with their own healthcare provider first.
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 May 24, 2013.
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 500 mg, straight from the product label.
| Brand | Nature's Harmony |
|---|---|
| Net contents | 90 Capsule(s) |
| Market status | On market |
| Date entered into DSLD | May 24, 2013 |
| DSLD ID | 21858 |
| Product type | Amino Acid/protein |
| Supplement form | Capsule |
| Dietary claims / uses | All Other, Qualified Health |
| Intended target group(s) | Adult (18 - 50 Years), Gluten Free, Dairy 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 500 mg by Nature's Harmony, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Lysine | 500 mg | -- |
Other ingredients: Calcium Silicate, Silicon Dioxide, Magnesium Stearate, Gelatin
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.
Suggested/Recommended/Usage/Directions
Recommended Use: Helps to reduce the recurrence, severity and healing time of cold sores. Recommended Dose (Adults): Take 2 capsules three times daily for up to six months.
Precautions
Risk Information: Do not use if pregnant or breastfeeding.
If symptoms persist, consult a health care practitioner.
KEEP OUT OF REACH OF CHILDREN.
DO NOT USE IF SEAL UNDER CAP IS BROKEN.
Formulation
This product does not contain any corn, dairy, egg, gluten, shellfish, soy, sulfites, or artificial colours, flavours or preservatives.
Storage
STORE IN A COOL DRY PLACE.
General Statements
Helps Reduce Cold Sore Severity
{Capsule} Actual Size
A Proud Canadian Company
UPC CODE TO BE: 0 63047 40085 1
General
400850.01-05
Seals/Symbols
SunOpta A healthy products company
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine 500 mg by Nature's Harmony 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 500 mg by Nature's Harmony
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size2 Capsule(s) Dosage formCapsule 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: Calcium Silicate, Silicon Dioxide, Magnesium Stearate, Gelatin. These complete the product’s ingredient list but are not active constituents.
L-Lysine 500 mg by Nature's Harmony Drug Interactions
HelloPharmacist Interaction Report
L-Lysine 500 mg by Nature's Harmony has one documented interaction.
Through its L-lysine content, it may reduce the effects of 5-HT4 agonists (medications that work on serotonin receptor 4). Animal research suggests lysine acts as a partial antagonist—meaning it can block some of what these drugs are trying to do—which could make them less effective at controlling symptoms like diarrhea.
Read the full breakdown — every affected drug type, severity by severity
Additionally, this is a Minor interaction, so the practical impact is likely small. But if you take a 5-HT4 agonist, it's worth mentioning this supplement to your doctor or pharmacist before starting it.
Altogether, these interactions span 1 individual medication.
To check whether your specific drugs are affected, use the interaction tool below and run through your complete medication list.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Lysine 500 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 500 mg interact with 1 drug. Click any drug to see the details.
1 of the 1 ingredient in L-Lysine 500 mg interact with drugs. Each result below shows which ingredient is responsible. L-Lysine
TegaserodZelnorm
How Tegaserod interacts with L-Lysine 500 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 500 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 500 mg, from the product label.
Nature's Harmony
See all Nature's Harmony products- Name
- SunOpta Inc.
- Street Address
- 6 Commerce Crescent
- City
- Acton
- State
- ON
- ZipCode
- L7J 2X3
L-Lysine 500 mg by Nature's Harmony: Common Questions
Does L-Lysine 500 mg by Nature's Harmony interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Will L-lysine help with cold sores?
What side effects might I notice?
Is it safe to take while pregnant?
What about breastfeeding?
Does high dose lysine cause problems?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Lysine 500 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 500 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 500 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