L-Lysine Ingredients & Drug Interactions
What is this page for?
First and foremost: checking L-Lysine 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 is a dietary supplement by Designs for Health 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 by Designs for Health
Ask about any prescription or over-the-counter medication and we check it for interactions with L-Lysine by Designs for Health — 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 by Designs for Health
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 a single active ingredient: L-lysine hydrochloride, an amino acid your body uses to build proteins and support immune function. It's rounded out with two inactive ingredients — cellulose and vegetable stearate — that serve as filler and lubricant in the capsule.
Does it work?
Moderate evidence
L-lysine is possibly effective for herpes labialis, commonly known as cold sores. The evidence supporting this use exists, though it's not conclusive enough to call it proven.
For other uses — child growth, pressure ulcers, and diabetic foot ulcers — we don't have enough reliable evidence to rate whether it works.
How safe is it?
Well-documented data
L-lysine is generally well tolerated at typical doses. At higher amounts, some people report stomach upset, abdominal pain, diarrhea, and indigestion.
Long-term safety at high doses hasn't been well studied. There is one rare case report of kidney problems linked to oral lysine use, though this is not a common concern.
Lysine from food is safe in pregnancy, but supplement safety during pregnancy and breastfeeding hasn't been well studied. If you're pregnant or nursing, talk with your doctor or pharmacist before starting a lysine supplement.
Meds to double-check
Minor interactions only
If you take a 5-HT4 agonist — a medication that works on serotonin receptors in the digestive tract — let your doctor or pharmacist know before starting this product, as lysine may reduce its effectiveness.
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 and is generally well tolerated at normal doses. If you take a 5-HT4 agonist (a gut-directed medication), check with your doctor or pharmacist first.
Anyone pregnant or breastfeeding should confirm safety with their own healthcare provider before 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 Aug 23, 2022.
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, straight from the product label.
| Brand | Designs for Health |
|---|---|
| Net contents | 120 Vegetarian Capsule(s) |
| Market status | On market |
| Date entered into DSLD | Aug 23, 2022 |
| DSLD ID | 276165 |
| Product type | Amino Acid/protein |
| Supplement form | Capsule |
| Dietary claims / uses | Nutrient, All Other |
| Intended target group(s) | Vegetarian, 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 by Designs for Health, sourced from the NIH Dietary Supplement Label Database.
Supplement Facts
| Ingredient | Amount | % DV |
|---|---|---|
| L-Lysine Hydrochloride | 1.5 Gram(s) | -- |
Other ingredients: Cellulose, Vegetable 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.
Formula
Free form essential amino acid
FDA Statement of Identity
Dietary Supplement
Precautions
For professional use only
Formulation
Gluten free formula Dairy free formula Soy free formula Non GMO Ingredients
Vegetarian formula
Suggested/Recommended/Usage/Directions
Recommended Use: As a dietary supplement, take two capsules per day, or as directed by your healthcare practitioner.
Is this label outdated? Report a formula or label change and our pharmacy team will review it.
L-Lysine by Designs for Health 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 by Designs for Health
This is the 1 active ingredient this product is made of. Select it to open its full monograph.
Serving size2 Capsule(s) Dosage formCapsule Servings per container60 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 & interactionsOther (inactive) ingredients: Cellulose, Vegetable Stearate. These complete the product’s ingredient list but are not active constituents.
L-Lysine by Designs for Health Drug Interactions
HelloPharmacist Interaction Report
Designs for Health L-Lysine has one documented interaction we hold data for.
Through its lysine content, it may reduce the effects of 5-HT4 agonists (medications that work on serotonin receptor 4 in the gut). Animal research suggests lysine acts as a partial blocker of this receptor, which theoretically could lower how well these drugs work.
Read the full breakdown — every affected drug type, severity by severity
That said, this is a Minor interaction based on animal data — human evidence of a real problem is limited. Still, if you take a 5-HT4 agonist, it's worth confirming with your doctor or pharmacist before adding lysine.
Use the medication checker on this page to look up your exact prescriptions, or talk with your own pharmacist to be sure.
Check your own medications below · Editorial policy · How we use AI
Want to check YOUR meds against L-Lysine?
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 interact with 1 drug. Click any drug to see the details.
1 of the 1 ingredient in L-Lysine interact with drugs. Each result below shows which ingredient is responsible. L-Lysine Hydrochloride
TegaserodZelnorm
How Tegaserod interacts with L-Lysine — through 1 ingredient. Tap an ingredient for the detail:
L-lysine Hydrochloride5-ht4 Agonists Minor
Interaction Summary
Theoretically, lysine may reduce the effects of 5-HT4 agonists.
Read the full L-lysine Hydrochloride + Tegaserod interactionEach ingredient & the kinds of drugs it affects
For each ingredient in L-Lysine 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, from the product label.
L-Lysine by Designs for Health: Common Questions
Does L-Lysine by Designs for Health interact with any medications?
How can one product interact with so many drugs?
Where does this information come from?
Does L-lysine actually help cold sores?
What side effects should I watch for?
Is it safe if I'm pregnant or breastfeeding?
What is L-lysine and what does it do?
Does this product contain fillers?
Written and reviewed by the HelloPharmacist editorial staff. Our editorial policy
Not sure if L-Lysine 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’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'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