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Dietary supplement

L-Lysine 500 mg Ingredients & Drug Interactions

by Doctor's Best

L-Lysine 500 mg label
See full label image
Capsule Category: Amino Acid/protein
Most serious interaction: Minor
Clinical methodology reviewed by · Updated Sep 16, 2026 · Label data from the NIH DSLD
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

The interaction bottom line Most serious interaction: Minor

L-Lysine 500 mg is a dietary supplement by Doctor's Best 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.

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Check Your Meds Against L-Lysine 500 mg by Doctor's Best

Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine 500 mg by Doctor's Best — and tell you which ingredient is responsible.

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HelloPharmacist Scorecard of L-Lysine 500 mg by Doctor's Best

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.

From our pharmacy team — supplement deep dive

Generated from HelloPharmacist’s pharmacist-curated databases and editorial rules · Last generated Aug 13, 2026

What’s inside

Full disclosure
Ingredient Transparency · database check
Full

Every active ingredient lists its own amount on the label.

Why this rating?
  • The label discloses an exact amount for 1 of its 1 active ingredient.
  • No proprietary blends here — you can verify the dose of every single component.

This product contains one active ingredient: L-lysine hydrochloride, an amino acid your body uses to build and repair proteins. The capsule also contains modified cellulose as an inactive ingredient.

Does it work?

Moderate evidence
Evidence for Intended Use · database check
By FDA rules, dietary supplements can’t claim to treat, cure, or prevent disease — so labels speak in careful marketing language. We discern each product’s intended use from its name, label claims, and label statements, then grade the clinical evidence for that use. How these ratings are computed
Moderate

Some clinical evidence supports this product's ingredients for its stated purpose, but it isn't conclusive.

Why this rating?
  • The label markets this product for: skin and tissue protection.
  • We looked for evidence on: Herpes labialis (cold sores), Pressure ulcers, Wound healing, Collagen synthesis.
  • The strongest evidence on file: Lysine is rated "Possibly Effective" for Herpes labialis (cold sores) (Natural Medicines).
  • Also on file: Lysine is rated "Insufficient Reliable Evidence To Rate" for Pressure ulcers.

L-lysine is possibly effective for herpes labialis, also called cold sores — the evidence suggests it may help, though more research would strengthen that claim. For child growth, pressure ulcers, and diabetic foot ulcers, we don't yet have enough reliable evidence to say whether it works.

The evidence, ingredient by ingredient Lysine

How safe is it?

Well-documented data
Safety Information · database check
Well characterized

Adverse-effect, pregnancy, and general safety data are on file for most of these ingredients.

Why this rating?
  • We hold adverse-effect (side-effect) data for 1 of the 1 matched ingredient.
  • Pregnancy & breastfeeding safety ratings cover 1 of 1.
  • General safety write-ups exist for 1 of 1.
  • Remember: this measures how much safety information exists. Thin data is not the same as being safe.

L-lysine from food is fine. Orally, the supplement is generally well tolerated, but high amounts may cause stomach upset, diarrhea, abdominal pain, or indigestion.

Long-term safety at high doses isn't well studied. Supplement safety in pregnancy and breastfeeding hasn't been well studied — the data we hold advises caution and recommends talking with your doctor first if you're pregnant or breastfeeding.

There is one rare case report of kidney inflammation linked to oral lysine use, though this was not common.

Side effects, ingredient by ingredient Lysine

Meds to double-check

Minor interactions only
Known Interaction Concern · database check
Minor only

Only Minor-severity interactions are documented for these ingredients.

Why this rating?
  • 1 of the 1 matched ingredient can interact with medications — Lysine.
  • The most serious interaction on file is rated Minor.
  • For scale: 1 individual medications appear in the full list. A big number alone doesn't make a product dangerous — what matters is whether YOUR medication is on it, so run yours through the interaction checker on this page.

If you take a 5-HT4 agonist (a drug used for certain digestive problems), check with your doctor or pharmacist before starting L-lysine — the supplement may reduce how well the medication works. No other interactions are documented for the ingredient we checked.

Check your own medication Run your meds through the checker above

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 worth considering if you get cold sores and want to try an amino acid approach, since it's possibly effective for that. If you take a 5-HT4 agonist or are pregnant or breastfeeding, talk with your doctor or pharmacist before starting.

At typical doses it's generally well tolerated, but high amounts can upset your stomach.

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 Mar 25, 2015.

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

At a glance

General information

Key facts about L-Lysine 500 mg, straight from the product label.

Brand Doctor's Best
Barcode (UPC) 753950003767
Net contents 120 Veggie Cap(s); 500 mg
Market status On market
Date entered into DSLD Mar 25, 2015
DSLD ID 43973
Product type Amino Acid/protein
Supplement form Capsule
Dietary claims / uses Nutrient, All Other, Structure/Function
Intended target group(s) Vegan, Vegetarian, Adult (18 - 50 Years), Gluten Free
From the label
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 Doctor's Best, sourced from the NIH Dietary Supplement Label Database.

Supplement Facts

Daily Value (DV) Target Group(s):
Adults and children 4 or more years of age
Minimum serving Sizes:
1 Capsule(s)
Maximum serving Sizes:
1 Capsule(s)
Servings per container
120
UPC/BARCODE
753950003767
IngredientAmount% DV
L-Lysine Hydrochloride500 mg--

Other ingredients: Modified Cellulose

Tap any ingredient to jump to its full detail below.

Label statements
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

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SKIN & TISSUE PROTECTION*

L-Lysine cannot be manufactured by the body and must be obtained through the diet or supplementation.*

Skin & tissue protection* Supports immune system* Helps restore L-Arginine /L-Lysine balance*

Seals/Symbols

Vegan(TM)

Suggested/Recommended/Usage/Directions

Suggested Adult Use: Take 1 capsule twice daily, with or without food, or as recommended by a nutritionally informed physician.

Formulation

Non-GMO / Gluten Free

Vegan

Storage

Store in a cool dry place.

General

YDRB376

Formula

Doctor’s Best L-Lysine supplies the pure form of L-Lysine, an essential amino acid that has many important functions in the body.*

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.

Brand IP Statement(s)

Science-Based Nutrition(TM)

FDA Statement of Identity

Dietary Supplement

Is this label outdated? Report a formula or label change and our pharmacy team will review it.

See for yourself

L-Lysine 500 mg by Doctor's Best label

The label scan from the NIH Dietary Supplement Label Database. Tap to enlarge.

L-Lysine 500 mg label

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)
What’s inside

The Ingredients in L-Lysine 500 mg by Doctor's Best

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 container120 Amounts shown are per serving.

L-Lysine Hydrochloride

Interacts with
1 drug
500 mg per serving

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

Other (inactive) ingredients: Modified Cellulose. These complete the product’s ingredient list but are not active constituents.

Interaction report

L-Lysine 500 mg by Doctor's Best Drug Interactions

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 checker
1Drugs
1 Minor

Ingredients driving the most interactions

L-Lysine Hydrochloride 1

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 Hydrochloride

Each 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 Hydrochloride1 drug type · 1 drug

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.

Likelihood Unlikely Evidence D
L-Lysine Hydrochloride full monograph & interactions
The maker

Brand information

Manufacturer and brand details for L-Lysine 500 mg, from the product label.

Doctor's Best

See all Doctor's Best products
Name
Doctor's Best, Inc.
City
San Clemente
State
CA
ZipCode
92673
Phone Number
(800) 777-2474
Web Address
www.drbvitamins.com
Pharmacist Counseling Corner

L-Lysine 500 mg by Doctor's Best: Common Questions

Does L-Lysine 500 mg by Doctor's Best interact with any medications?
Yes. Based on its ingredients, L-Lysine 500 mg has a known interaction with 1 medication. Use the checker to see how it interacts with a specific drug.
How can one product interact with so many drugs?
L-Lysine 500 mg contains a single active ingredient, and that one ingredient can interact with many different medications on its own. We check it against each medication and show the mechanism responsible.
Where does this information come from?
The product label data comes from the NIH Dietary Supplement Label Database (DSLD); the interaction data is built on the Natural Medicines database and reviewed by HelloPharmacist pharmacists.
Can I take L-lysine if I'm pregnant or breastfeeding?
Supplement safety in pregnancy and breastfeeding hasn't been well studied, so the data we hold advises caution. Talk with your doctor or pharmacist before taking it — they can help you decide what's right for your situation.
What side effects might I get from this?
At typical doses, L-lysine is generally well tolerated. Higher amounts may cause stomach upset, diarrhea, abdominal pain, or indigestion. There is one rare case report of kidney inflammation, though this was not common.
Does L-lysine really work for cold sores?
L-lysine is possibly effective for cold sores — the evidence suggests it may help, though more research would make that claim stronger. Results vary from person to person.
What is L-lysine and what does it do?
L-lysine is an amino acid, a building block your body uses to make and repair proteins. It's found in foods like meat, dairy, and legumes, and this supplement provides it in a concentrated form.
Should I worry about the inactive ingredient?
This product contains modified cellulose as an inactive ingredient — it's a binder that holds the capsule together. It's not an active part of the supplement and generally well tolerated.

Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy

Not sure if L-Lysine 500 mg is safe with your meds?

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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.

L-Lysine 500 mg label
Go deeper

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.

Herb & supplement monograph

Lysine

Interacts with 1 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 try to prevent or shorten cold sores, but...

Read the full Lysine monograph →
Sources

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.

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
  1. 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
  2. McCune MA, Perry HO, Muller SA, O'Fallon WM. Treatment of recurrent herpes simplex infections with L-lysine monohydrochloride. Cutis 1984;34:366-73.
  3. DiGiovanna JJ, Blank H. Failure of lysine in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Arch Dermatol 1984;120:48-51. DOI
  4. 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.
  5. 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
  6. 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
  7. 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.

See these in context on the Lysine monograph →

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

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