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 Puritan's Pride 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 Puritan's Pride
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine 500 mg by Puritan's Pride — 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 Puritan's Pride
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 supplement contains one active ingredient: L-lysine, an amino acid (a building block of protein) at 500 mg per capsule. The remaining ingredients — gelatin, silica, and magnesium stearate — are inactive fillers and capsule material 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 suggests it may help, though research is still limited.
For other uses listed — child growth, pressure ulcers, and diabetic foot ulcers — there isn't enough reliable evidence in the data we hold to say whether it works.
How safe is it?
Well-documented data
L-lysine is generally well tolerated at typical doses. The most common side effects from oral use are stomach upset — abdominal pain, diarrhea, and indigestion — especially at high amounts.
Long-term safety at higher doses hasn't been well studied. For pregnancy, the safety of L-lysine supplements hasn't been well studied either, so talk with your doctor before taking it if you're pregnant or breastfeeding — the data we hold doesn't give us a clear answer either way.
Meds to double-check
Minor interactions only
If you take a 5-HT4 agonist, L-lysine may reduce how well it works. Check with your doctor or pharmacist before combining them.
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 may be worth trying if you're dealing with cold sores and want a possibly effective option. If you take medications — especially any that work on serotonin receptors in your gut — check with your doctor or pharmacist first.
Stick to typical doses to lower your chance of stomach upset, and don't hesitate to ask your healthcare provider about long-term use.
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, 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 500 mg, straight from the product label.
| Brand | Puritan's Pride |
|---|---|
| Barcode (UPC) | 025077128068 |
| Net contents | 100 Rapid Release Capsule(s) |
| Market status | On market |
| Date entered into DSLD | May 24, 2023 |
| DSLD ID | 285039 |
| Product type | Amino Acid/protein |
| Supplement form | Capsule |
| Dietary claims / uses | Nutrient, 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 500 mg by Puritan's Pride, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Lysine | 500 mg | -- |
Other ingredients: Gelatin, 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
Puritan’s Pride supplements are produced from the finest raw materials under stringent quality control standards. State-of-the-art manufacturing and packaging facilities ensure you the highest quality nutritional supplements money can buy. When it comes to your health...choose the best.
To reorder item # 12806 www.puritan.com 1-800-645-1030
Precautions
Warning: If you are pregnant, nursing, taking any medications or have any medical condition, consult your doctor before use.
Discontinue use and consult your doctor if any adverse reactions occur.
Keep out of reach of children.
Do not use if seal under cap is broken or missing.
Storage
Store at room temperature.
Brand IP Statement(s)
Copyright 2017 Puritan’s Pride, Inc.
Seals/Symbols
QA Quality Assured
Formulation
Free form
No artificial color, flavor or sweetener, no preservatives, no sugar, no starch, no milk, no lactose, no soy, no gluten, no wheat, no yeast, no fish. Sodium free.
FDA Statement of Identity
Amino Acid Supplement
Suggested/Recommended/Usage/Directions
Directions: For adults, take one (1) capsule two to four times daily, preferably on an empty stomach.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine 500 mg by Puritan's Pride 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 Puritan's Pride
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size1 Capsule(s) Dosage formCapsule 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: Gelatin, Silica, Magnesium Stearate. These complete the product’s ingredient list but are not active constituents.
L-Lysine 500 mg by Puritan's Pride Drug Interactions
HelloPharmacist Interaction Report
Puritan's Pride L-Lysine 500 mg may interact with medications through its single active ingredient, L-lysine.
The most serious documented interaction is with 5-HT4 agonists (a class of drugs that work on serotonin receptors in the gut) — lysine may reduce their effectiveness. Animal research suggests lysine works as a partial blocker of these receptors, which could interfere with how the drug does its job.
Read the full breakdown — every affected drug type, severity by severity
Although we have only one documented drug interaction in our data, it's labeled Minor in severity. If you take a 5-HT4 agonist, you'll want to run it through the checker below or ask your doctor or pharmacist before adding this supplement.
Altogether, these interactions span 1 individual medication. The data we hold doesn't cover every possible medication interaction, so checking your exact medications with the tool on this page is the best next step.
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.
Puritan's Pride
See all Puritan's Pride products- Name
- Puritan's Pride, Inc.
- City
- Ronkonkoma
- State
- NY
- ZipCode
- 11779
- Phone Number
- 1-800-645-1030
- Web Address
- www.puritan.com
L-Lysine 500 mg by Puritan's Pride: Common Questions
Does L-Lysine 500 mg by Puritan's Pride interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Will L-lysine help me get rid of a cold sore?
What side effects should I watch for?
Is it safe to take L-lysine while I'm pregnant?
Can I take L-lysine while breastfeeding?
Why does this supplement have so few ingredients?
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