NutriStack
L-Lysine and Valacyclovir, a synergy.
Valacyclovir is the prodrug of acyclovir, and L-lysine prophylaxis works through a separate, arginine-competition mechanism against HSV. Evidence is modest and best supported for daily doses above 1 g, but there is no known pharmacokinetic interaction with valacyclovir, and combination use is reasonable for recurrence prevention.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- L-Lysine and Valacyclovir
- Pair type
- Synergy
- Evidence (highest tier)
- Emerging
- Source citations
- 2 sources
- Stack Score effect
- +2 to your Stack Score (per scored synergy row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Synergy · Emerging evidence
Synergy
What is happening. Valacyclovir is the prodrug of acyclovir, and L-lysine prophylaxis works through a separate, arginine-competition mechanism against HSV. Evidence is modest and best supported for daily doses above 1 g, but there is no known pharmacokinetic interaction with valacyclovir, and combination use is reasonable for recurrence prevention.
Mechanism. Lysine competes with arginine, which HSV requires for capsid protein synthesis. Valacyclovir is converted to acyclovir, which inhibits viral DNA polymerase. The mechanisms do not overlap or interfere.
Recommendation. Lysine 1-3 g/day is a reasonable adjunct to valacyclovir for recurrent HSV. Continue valacyclovir as prescribed during active outbreaks; do not rely on lysine alone.
Sources (2)
- Mailoo VJ, Rampes S. Lysine for herpes simplex prophylaxis: a review of the evidence. Integr Med (Encinitas). 2017;16(3):42-46. PMID 30881246
- Griffith RS, et al. Success of L-lysine therapy in frequently recurrent herpes simplex infection. Treatment and prophylaxis. Dermatologica. 1987;175(4):183-90. PMID 3115841
Stack Score
How this pair moves the number.
Effect on the composite score
If both L-Lysine and Valacyclovir are in the same stack, this pair applies +2 to your Stack Score (per scored synergy row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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