L-Lysine 1,500 mg Ingredients & Drug Interactions
by Dr. Mercola
What is this page for?
First and foremost: checking L-Lysine 1,500 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 1,500 mg is a dietary supplement by Dr. Mercola 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 1,500 mg by Dr. Mercola
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine 1,500 mg by Dr. Mercola — 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 1,500 mg by Dr. Mercola
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 (a building block of protein). L-lysine is supplied as a 1,500 mg dose per capsule.
The capsule also includes two inactive ingredients — rice bran and hydroxypropyl methylcellulose — which serve as filler and capsule material.
Does it work?
Moderate evidence
L-lysine is possibly effective for herpes labialis (cold sores) based on the evidence we have. For other uses listed — child growth, pressure ulcers, and diabetic foot ulcers — there isn't enough reliable evidence yet to know whether it works.
How safe is it?
Well-documented data
L-lysine is generally well tolerated at typical doses. At higher amounts, stomach upset can occur, and long-term safety hasn't been thoroughly studied.
The most common side effects from oral use are abdominal pain, diarrhea, and indigestion. There is one case report linking high-dose oral lysine to a kidney condition, though this is rare.
During pregnancy, lysine from food is fine, but supplement safety hasn't been well studied — check with your doctor first. For breastfeeding, there isn't enough reliable information, so caution is advised; talk to your pharmacist or doctor for personalized guidance.
Meds to double-check
Minor interactions only
If you take a 5-HT4 agonist (a medication for certain digestive issues), double-check with your pharmacist before starting this product — lysine may reduce how well it works.
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 may help with cold sores if you want to try it. If you take a 5-HT4 agonist medication, check with your pharmacist first.
Pregnant or breastfeeding? Talk to your doctor before starting, since long-term safety data is limited.
At high doses, watch for stomach upset.
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 Jun 25, 2025.
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 1,500 mg, straight from the product label.
| Brand | Dr. Mercola |
|---|---|
| Barcode (UPC) | 810094213817 |
| Net contents | 90 Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Jun 25, 2025 |
| DSLD ID | 327176 |
| Product type | Amino Acid/protein |
| Supplement form | Capsule |
| Dietary claims / uses | Nutrient, All Other, Structure/Function |
| Intended target group(s) | Adult (18 - 50 Years) |
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 1,500 mg by Dr. Mercola, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Lysine | 1500 mg | -- |
Other ingredients: Rice Bran, Hydroxypropyl Methylcellulose
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
Suggested use: Adults, as a dietary supplement, take one (1) capsule three times daily.
Precautions
Keep out of reach of children.
If you are nursing, pregnant, taking medication or have a medical condition, consult your physician before taking this product.
Do not use if safety seal is broken.
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.
Formulation
Immune support Metabolic health Energy production
Formula
L-Lysine 1,500 mg per day
FDA Statement of Identity
Dietary Supplement
General Statements
Providing quality products since 2001.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine 1,500 mg by Dr. Mercola 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 1,500 mg by Dr. Mercola
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 container90 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: Rice Bran, Hydroxypropyl Methylcellulose. These complete the product’s ingredient list but are not active constituents.
L-Lysine 1,500 mg by Dr. Mercola Drug Interactions
HelloPharmacist Interaction Report
L-Lysine 1,500 mg by Dr.
Mercola has one documented drug interaction. Lysine may reduce the effects of 5-HT4 agonists — a class of medications used mainly for certain gastrointestinal issues.
Animal research suggests lysine acts as a partial blocker of the serotonin receptor these drugs target, which could weaken their intended effect.
Read the full breakdown — every affected drug type, severity by severity
Although this is the only interaction we have data for, it's rated Minor in severity. If you take a 5-HT4 agonist, it's worth checking in with your pharmacist before starting lysine to make sure your medication stays effective.
Use the medication checker on this page to verify your specific drugs.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Lysine 1,500 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 1,500 mg interact with 1 drug. Click any drug to see the details.
1 of the 1 ingredient in L-Lysine 1,500 mg interact with drugs. Each result below shows which ingredient is responsible. L-Lysine
TegaserodZelnorm
How Tegaserod interacts with L-Lysine 1,500 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 1,500 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 1,500 mg, from the product label.
Dr. Mercola
See all Dr. Mercola products- Name
- NHP
- Street Address
- 125 SW 3rd Place
- City
- Cape Coral
- State
- FL
- ZipCode
- 33991
- Phone Number
- (877) 985-2696
L-Lysine 1,500 mg by Dr. Mercola: Common Questions
Does L-Lysine 1,500 mg by Dr. Mercola interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Will L-lysine help my cold sores?
Can I take this if I'm pregnant?
Is L-lysine safe while breastfeeding?
What are the side effects?
Is this safe for long-term use?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Lysine 1,500 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 1,500 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 1,500 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