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Reviewed by the Scan Dose Research Team and Clinical Advisory Board

L-Lysine

MODERATE EVIDENCEAmino AcidLast updated

SCAN DOSE SUMMARY

L-lysine is an essential amino acid with two primary supplemental uses: (1) herpes simplex virus (HSV) outbreak prevention (the most popular use), and (2) calcium absorption enhancement. The HSV mechanism is elegant: lysine competes with arginine for absorption and cellular entry, and HSV requires arginine for replication. By shifting the lysine:arginine ratio, viral replication is suppressed. A meta-analysis found 1g+/day reduced HSV recurrence rate by 25-50%. Our research also shows lysine is essential for collagen synthesis (lysyl oxidase cross-links collagen), making it relevant for wound healing and connective tissue.

WHAT IT DOES

For HSV: the virus requires arginine for capsid protein synthesis and DNA replication. Lysine and arginine compete for the same intestinal transporter (CAT-1) and cellular entry mechanisms. High lysine intake (1) reduces arginine absorption, (2) reduces arginine entry into cells, (3) increases arginase activity (breaking down intracellular arginine). The net effect: reduced intracellular arginine starves the virus of a replication requirement. For collagen: lysine residues in procollagen are hydroxylated by lysyl hydroxylase (vitamin C-dependent) and then oxidatively cross-linked by lysyl oxidase (copper-dependent), forming the structural cross-links that give collagen tensile strength.

OPTIMAL DOSAGE

  • Look for: L-lysine HCl; 500-1,000mg per capsule; free-form amino acid
  • Avoid: D-lysine; products with added arginine (counterproductive for HSV); very low doses (<250mg)
  • Minimum effective dose: 1,000mg/day for HSV prevention
  • Third-party tested brands: NOW Foods, Quantum Health (Super Lysine+), Thorne, Life Extension
Scan a supplement containing L-Lysine

SAFETY PROFILE

Critical Interactions (Do Not Combine Without Medical Supervision)

No critical interactions identified.

Moderate Interactions (Monitor Closely)

Theoretical/Low-Risk Interactions

RELATED RESEARCH

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L-ArginineMeta-analysis of 11 RCTs: arginine reduced systolic BP by 5.39 mmHg and diastolic by 2.66 mmHg at do
BCAAs / EAAs
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Reviewed by the Scan Dose Research Team and Clinical Advisory Board | Last updated:

Not medical advice. Based on published clinical research and systematic reviews.

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