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L-Lysine Hydrochloride: An Alternative Prophylactic Therapy Reducing the Recurrence Rate of Herpes Labialis

8 August 2015


Background: 57.7% of the US population between the ages of 14-49 years is seropositive to antibodies for the herpes simplex virus type 1 (HSV1). It has been concluded in studies that lysine, an essential amino acid, inhibits the multiplication of HSV1 in cell cultures when there is high concentration of lysine in the culture medium. Conversely, arginine, a natural amino acid is required for viral replication. At the cellular level, lysine acts as a herpes virus inhibitor by antagonizing arginine. An effective treatment in the prevention of recurrent HSV1 outbreaks has the potential to impact daily living. Could lysine become an effective prophylactic treatment that reduces the recurrence rate of herpes labialis outbreaks?

Methods: An exhaustive search was conducted using Medline-OVID, CINAHL, Web of Science, Google Scholar using the keywords: lysine, L-lysine, oral herpes simplex, herpetic stomatitis, herpes simplex, HSV-1, herpesvirus 1, herpes labialis, prevention, and prophylactic. Relevant articles were assessed for quality using GRADE. A search on the National Institute of Health (NIH) clinical trials site revealed no currently registered trials, at any phase, relating to the use of L-lysine for prophylactic treatment of herpes labialis.

Results: Two randomized, double blind, placebo-controlled trials met inclusion criteria and were included in this systematic review. The first study with 26 participants demonstrated a strong association between high serum lysine levels and a decrease in lesion frequency suggesting that prophylactic lysine may be useful in managing select cases of recurrent herpes labialis. The second trial with 65 participants demonstrated no statistically significant reduction in the number of herpes labialis recurrences during the trial; however, the results suggest that certain patients may benefit from prophylactic lysine therapy with a reduction in herpes labialis and this requires further investigation.

Conclusion: The effects of L-lysine prophylactic therapy in suppression of herpes labialis is clear but not for all individuals. Supplemental L-lysine taken at recommended dosages provides a prophylactic therapy benefit to patients whose body responds to the supplementation with an increase in serum lysine levels. Treatment effect seems to vary per person depending on serum lysine levels. The questions remaining are what is the optimal lysine serum level to provide protection for a majority of persons from herpetic outbreaks and is it consistently attainable with individual variables such as patient response to supplementation? L-lysine prophylactic therapy is a cost efficient safe therapy to be considered by patients who are open to trying alternative treatments for herpes labialis.


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