Compound or practice · Supplement
L-Lysine
An essential amino acid with modest evidence for reducing cold-sore (herpes) recurrences.
- Overall grade
- Grade C
- Last revised
- 1
- graded outcome
- 0
- references listed
A structured monograph in Prometheus's bundled library. Its grades are the monograph's own reading of the evidence, not a peer-reviewed review.
2 at grade C — 2 graded rows
What is known
Each outcome with its grade (how strong the evidence is, A to D), the size of the effect where the entry records one, and how often studies agree.
- Cold-sore (HSV) recurrenceEvidence grade C
Higher doses
Smallmixed
Conditions
How the entry reads its effect on diagnosed conditions: the direction first, then the grade. Never a substitute for the person who treats you.
- Recurrent cold sores May improveEvidence grade CPreventionGrade C
What is uncertain
Read off the same rows as above. Nothing here is added that the entry does not itself record.
- Thin evidence: Cold-sore (HSV) recurrence (grade C).
The evidence in words
What it is
L-lysine is an essential amino acid taken to reduce herpes-simplex cold-sore outbreaks.
How it works
Lysine competes with arginine, which the herpes virus needs to replicate — the basis for the lysine/arginine-balance approach.
What the evidence shows
Small trials suggest higher-dose lysine reduces cold-sore frequency and severity for some, though results are mixed. Cheap and low-risk; not a cure.
How to use it
1–3 g/day for prevention; higher at outbreak onset.
Safety & interactions
Generally safe; GI upset at high doses; caution in kidney disease.
Bottom line
A cheap, low-risk option that helps some people get fewer cold sores. Worth a trial if you're prone to them.
How it is used
As the entry records it, from the studies it summarises. Not a recommendation for you — doses that suit a trial population may not suit you.
- Standard
- 1–3 g/day prevention.
Related reading
Entries that share this one's tags or conditions.
- L-Lysine for Cold-sore (HSV) recurrenceEvidence grade C — Higher dosesEvidence grade C
- L-Lysine for Recurrent cold soresEvidence grade C — PreventionEvidence grade C
- L-Lysine: dosage and how to take it1–3 g/day prevention.Evidence grade C
- L-Lysine: side effects, safety & interactionsGenerally safe; GI upset at high doses; caution in kidney disease.Evidence grade C
Sources
This entry lists no references of its own.
Last revised . A grade is this entry's reading of the evidence, not medical advice.