L-Lysine Hydrochloride 500 mg Ingredients & Drug Interactions
What is this page for?
First and foremost: checking L-Lysine Hydrochloride 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 Hydrochloride 500 mg is a dietary supplement by Highland Laboratories 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 Hydrochloride 500 mg by Highland Laboratories
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine Hydrochloride 500 mg by Highland Laboratories — 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 Hydrochloride 500 mg by Highland Laboratories
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, a form of the amino acid lysine. The capsule also holds inactive ingredients — gelatin, magnesium trisilicate, silica, and magnesium stearate — which are standard fillers and binders that help hold the supplement together.
Does it work?
Moderate evidence
L-lysine is possibly effective for herpes labialis, commonly called cold sores. The evidence supporting its use for other purposes — including child growth, pressure ulcers, and diabetic foot ulcers — is insufficient or not well established in the data we hold.
How safe is it?
Well-documented data
L-lysine is generally well tolerated at typical doses. At higher amounts, it may cause stomach upset, including abdominal pain, diarrhea, and indigestion.
Long-term safety at high doses hasn't been well studied. Lysine from food is considered safe during pregnancy, but safety data for supplements during pregnancy isn't well established — check with your doctor before taking this if you're pregnant.
There isn't enough reliable information on supplement use while breastfeeding, so talk with your doctor or pharmacist for personalized advice.
Meds to double-check
Minor interactions only
If you take a 5-HT4 agonist (a serotonin-pathway drug used mainly for certain gut conditions), let your doctor or pharmacist know before taking L-lysine — animal data suggests it may reduce the drug's effect, though human evidence is limited.
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 is possibly effective for cold sores if that's what you're taking it for. It's generally well tolerated, though higher doses may cause digestive upset.
If you take a 5-HT4 agonist, check with your doctor or pharmacist before starting. Pregnant or breastfeeding?
Talk with your 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 Oct 21, 2017.
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 Hydrochloride 500 mg, straight from the product label.
| Brand | Highland Laboratories |
|---|---|
| Barcode (UPC) | 768305974104 |
| Net contents | 100 Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Oct 21, 2017 |
| DSLD ID | 79663 |
| Product type | Other Combinations |
| Supplement form | Capsule |
| Dietary claims / uses | All Other |
| Intended target group(s) | 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 Hydrochloride 500 mg by Highland Laboratories, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Lysine Hydrochloride | 500 mg | -- |
| L-Lysine | 400 mg | -- |
Other ingredients: Gelatin, Magnesium Trisilicate, Silica, 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.
General Statements
Also available in 250 count
% Daily Value
Formula
Free-form L-Lysine Hydrochloride (500 mg.)
FDA Statement of Identity
A Dietary Supplement
Seals/Symbols
GMP Quality Assured Earth Friendly
Formulation
No corn, soy, salt, yeast, gluten, milk & egg products, sugar, starch, or preservatives.
Suggested/Recommended/Usage/Directions
One or more capsules daily, in between meals, preferably with fruit juice. More effective when taken with carbohydrates, not protein.
General
PR 974
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine Hydrochloride 500 mg by Highland Laboratories 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 Hydrochloride 500 mg by Highland Laboratories
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Capsule(s) Dosage formCapsule 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 & interactions- › L-Lysine
Other (inactive) ingredients: Gelatin, Magnesium Trisilicate, Silica, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.
L-Lysine Hydrochloride 500 mg by Highland Laboratories Drug Interactions
HelloPharmacist Interaction Report
L-Lysine Hydrochloride 500 mg by Highland Laboratories contains one ingredient with documented interactions: L-lysine, which may affect 5-HT4 agonists (a class of drugs that work on serotonin pathways in the gut).
Animal research suggests lysine can block these drugs' effects, though the clinical significance isn't yet clear.
Read the full breakdown — every affected drug type, severity by severity
The interaction is classified as Minor — meaning the effect is unlikely to be severe, but it's worth knowing about. If you take a 5-HT4 agonist, talk with your doctor or pharmacist before starting this supplement to confirm it won't interfere with your treatment.
Although we've checked L-lysine thoroughly, we cannot verify interactions for all ingredients in this product. Use the medication checker on this page to search your exact prescriptions against L-Lysine Hydrochloride 500 mg.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Lysine Hydrochloride 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 Hydrochloride 500 mg interact with 1 drug. Click any drug to see the details.
1 of the 1 ingredient in L-Lysine Hydrochloride 500 mg interact with drugs. Each result below shows which ingredient is responsible. L-Lysine Hydrochloride
TegaserodZelnorm
How Tegaserod interacts with L-Lysine Hydrochloride 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 Hydrochloride 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 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 Hydrochloride 500 mg, from the product label.
L-Lysine Hydrochloride 500 mg by Highland Laboratories: Common Questions
Does L-Lysine Hydrochloride 500 mg by Highland Laboratories interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Will L-lysine actually help my cold sores?
What are the side effects?
Is it safe to take while pregnant?
Can I take it while breastfeeding?
How much is too much?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Lysine Hydrochloride 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 Hydrochloride 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 Hydrochloride 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