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📰Read the full L-Lysine evidence review on GMJ News →Complete clinical article, references and updates on news.gmj.ge. This page is the structured safety summary.⚠ HSV evidence is mixed/inconclusive — but low risk to try [2]
⚠ Lysine:arginine ratio theory is plausible (HSV needs arginine) [1]
⚠ Limiting amino acid in cereals — relevant for grain-heavy diets [1]
ℹ️ Not obtained from food. Obtained as part of dietary protein rather than tracked individually toward a daily target.
🔬 Lab interpreter
ℹ️ No validated blood test. There is no established laboratory test to assess status or guide dosing for this ingredient. Clinical response and symptoms are the practical guide.
⚕ For professionals — confirm ranges against your local laboratory.
Clinical verdict
Lysine is commonly taken for HSV (cold sore) prevention — lysine:arginine competition theory is plausible but evidence is INCONCLUSIVE (systematic review). Many patients report subjective benefit. Low risk to try. Also important for collagen synthesis and carnitine production. Limiting amino acid in grain-based diets [1] [2].
1 How much do I need?
👤 Adults: Specific dosage data under clinical review
👴 Elderly: Specific dosage data under clinical review
🤰 Pregnancy: See guidance
Essential amino acid. Dietary safe. Supplementation: no data [1].
👦 Pediatric: See guidance
Essential nutrient from food [1].
🏃 Athletes: Standard dose
⚖️ Obesity: Standard dose
Fat-soluble compounds may require dose adjustment in obesity.
🩺 Renal: Consult specialist
Dose adjustment may be needed in renal impairment.
🌱 Vegan: Standard dose
How to take
🍽 Timing: Divided doses. For HSV: continuous daily [2].
💊 With food: With or without food [1].
🚫 Avoid: No significant contraindications [1].
2 Which form?
| Form | Bioavailability | Vegan | Cost |
|---|---|---|---|
| ['L-Lysine HCl capsules/tablets', 'common', '500–1,000 mg per capsule. 1–3 g/day [1].'] | Standard | Check label | |
| ['L-Lysine powder', '', 'Bulk. For higher doses [1].'] | Standard | Check label | |
| ['L-Lysine cream (topical)', '', 'For cold sore application. Limited data [1].'] | Standard | Check label |
3 Common questions
Does lysine prevent cold sores? ▼
Should I avoid arginine-rich foods with HSV? ▼
The theory: HSV needs arginine to replicate; lysine competes with arginine for cellular uptake. Reducing nuts, chocolate, and seeds (arginine-rich) while increasing lysine intake is commonly recommended. Evidence is inconsistent but the practice is low-risk [1].
Is lysine deficiency common? ▼
In Western diets: rare. In grain-based diets (developing world): lysine is the limiting essential amino acid in cereals. Vegans on grain-heavy diets should ensure legume intake (lysine-rich) [1].
4 Clinical evidence
Strong
Lysine is essential for collagen synthesis and carnitine production — established biochemistry [1]. HSV requires arginine for replication — confirmed virology [1]. HIGH
Moderate
HSV prevention: some older RCTs showed reduced outbreak frequency and severity with 1–3 g/day [2]. Lysine:arginine ratio theory: plausible mechanism but inconsistently supported [2]. Calcium absorption: some evidence that lysine enhances intestinal calcium absorption [1]. MODERATE
Insufficient
5 Safety, toxicity & adverse events
Relative
⚠ Renal impairment — reduced clearance
⚠ High doses — GI upset; theoretical interaction with calcium handling
⚠ Concurrent aminoglycosides — theoretical additive renal caution
⚠ Pregnancy and lactation — food amounts safe; high-dose data limited
🚩 Red flags
● Patient expecting guaranteed HSV prevention — evidence is inconclusive [2]
6 Interactions
Supplement synergies
Vitamin C + Zinc · 1,000 mg C + 30 mg zinc
Immune support trio for HSV management [1].
Immune support trio for HSV management [1].
Proline + Vitamin C · 500 mg proline + 500 mg C
Collagen synthesis trio: lysine + proline + vitamin C [1].
Collagen synthesis trio: lysine + proline + vitamin C [1].
7 Regulatory
United States: GRAS. Dietary supplement [1].
8 US supplement products
32
on-market products containing L-Lysine (NIH DSLD)
Brands carrying L-Lysine (12)
Click a brand to see its L-Lysine products.
9 Frequently paired with
10 Cite this page
Vancouver: Pkhakadze G. L-Lysine — safety profile [Internet]. Tbilisi: PHIG; 2026 [cited 2026 Jul 15]. Available from: https://supplement.ge/ingredients/l-lysine/
APA 7th: Pkhakadze, G. (2026). L-Lysine — Safety profile. Public Health Institute of Georgia. https://supplement.ge/ingredients/l-lysine/
📋 Editorial information
Author: Prof. G. Pkhakadze, MD, MPH, PhD
Institution: Public Health Institute of Georgia (PHIG)
Affiliation: David Tvildiani Medical University (DTMU)
First published: January 2026
Last reviewed: 2026-05-29
Next review: January 2027
References: 2 cited sources
COI: SupplementIndex receives no funding from supplement manufacturers. All content independently authored by PHIG.
Process: Systematic literature review
📄 License & reuse
Published under Creative Commons Attribution 4.0 International (CC BY 4.0). You may share and adapt for any purpose with attribution.
Pkhakadze G. "L-Lysine — Safety Profile." SupplementIndex, PHIG, 2026. https://supplement.ge/ingredients/l-lysine/ CC BY 4.0.
GP
Prof. G. Pkhakadze, MD, MPH, PhD
Professor of Public Health · Head of Department, DTMU
Editor-in-Chief, Georgian Medical Journal (ISSN 3088-4322)
Chair, Public Health Institute of Georgia · UEMS Public Health Section
Educational and public health purposes. CC BY 4.0. Consult your healthcare provider before starting any supplement. Corrections: info@accreditation.ge. Publisher: PHIG