Amino Acid
L-Lysine
Also known as: Lysine, L-Lysine HCl, Lysine Monohydrochloride
Essential amino acid important for protein synthesis, collagen formation, calcium absorption, and immune function, particularly noted for antiviral properties.
Last reviewed June 2026 · Evidence graded from peer-reviewed research, not editorial opinion. Educational only — not medical advice.
Daily target & upper limit
1000 mg / dayL-Lysine has an established daily reference intake. See best forms, label synonyms, upper-limit warnings, and top-scoring supplements:
L-Lysine dosage reference →Primary uses
- Cold sore prevention
- Protein synthesis
- Collagen support
- Calcium absorption
How it works
- Competes with arginine for viral replication
- Essential for collagen synthesis
- Supports carnitine production
Dosage
- Typical range
- 500-3000 mg daily
- Timing
- Between meals or with meals
- With food
- Either way
- Duration
- Safe for long-term use
- Special populations
- Those prone to cold sores
Forms
- Free form· 95/100
- L-lysine monohydrochloride· 90/100
- L-lysine HCl· 90/100
Safety
Common side effects
- GI upset at high doses
Products containing L-Lysine
Top-scoring supplements in our catalog that list L-Lysine on the label. Each product is graded on Formulate's ingredient-level rubric — dose accuracy, form, transparency, and third-party testing.
Evidence notes
Good evidence for cold sore prevention, protein synthesis
Grade B: Some human trials support key claims; further confirmation needed.
Related in Amino Acid
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Medical disclaimer. This page is educational and does not replace advice from a qualified healthcare provider. Individual needs and risks vary — consult a professional before starting, stopping, or combining supplements, especially if you are pregnant or nursing, taking medication, or managing a health condition.