Treating / preventing cold sores: Lysine oral supplements.
L-lysine dietary supplements are frequently promoted as a do-it-yourself therapy that can help to:
- Minimize your frequency of cold sore (fever blister) outbreaks.
- Lessen the duration or severity of those outbreaks that do occur.
However, despite the widespread popularity of this advice (which is most notably touted by companies that sell lysine products) this treatment approach is only partially supported by medical research.
When considering taking lysine, don't over look other treatment approaches, such as other home remedies, non-prescription products and especially prescription antiviral medications that may be able to provide an equal, or possibly superior, solution solution.
This page will outline for you: Why lysine is thought to work. What does research into the subject show? Information about lysine dosing and precautions. As well as presenting an alternative approach to taking lysine supplements.
The basis of this treatment theory: The lysine/herpes virus relationship.
The theory associated with the use of lysine in treating fever blisters / cold sores is typically this:
- The herpes virus requires arginine (an amino acid) for certain vital functions such as protein synthesis and replication.
- Since lysine (another amino acid) and arginine share (and therefore compete for) common pathways when being transported throughout the body, an increased intake of lysine results in a comparatively smaller amount of arginine being available to the herpes virus for use.
- The net effect of this arginine deficit is that it creates an inhibitory effect on the normal formation cold sores.
How do the facts of this theory stack up?
A) To the credit of this theory, there is evidence that arginine is a requirement for proper herpes virus replication and that proteins synthesized by the herpes virus do contain more arginine and less lysine than those proteins synthesized by the host cells they live in.
B) What's not so clear cut is that the simple act of taking lysine supplements is effective in reducing the both the frequency and the duration and severity of cold sores. The research that has been published regarding this topic has been mixed. Studies seem to suggest that lysine supplements may help to reduce the frequency of fever blister outbreaks but they likely aren't effective in reducing the duration and severity of those outbreaks that do take place.
What does research into the use of L-lysine to treat cold sores show?
Tomblin & Lucas (2001) performed a literature review that evaluated seven (randomized, double-blind, placebo-controlled) research studies that had investigated the use of lysine in treating cold sores. These studies had been conducted between the years 1978 and 1997. (Our January 2011 search of the National Institute of Health's PubMed database using the keywords "lysine herpes labialis cold sores fever blisters" suggests that no similar studies have been published since then.)
The findings of this review were:
- Six out of the seven studies did show evidence that taking oral lysine supplements could be effective in decreasing the frequency of fever blister outbreaks.
- Only two of the studies showed evidence that taking lysine decreased the severity or duration of cold sore outbreaks.
So to recap, it seems that published research suggests that taking oral lysine supplements may be effective in helping to reduce (but not totally prevent) the occurrence of fever blister outbreaks. But it fails to confirm that this therapy has a treatment effect on those sores that do form (does not lessen symptoms or reduce healing time).
Should you take lysine supplements?
You'll have to decide, hopefully together with your health care provider, if taking lysine supplements is the right approach for you. Please keep in mind that the studies mentioned above are only evaluations of a treatment approach. And while collectively they do seem to suggest that taking oral lysine supplements may have merit, this therapy this should still be considered to be an unproven treatment.
We will mention:
1) The FDA has not approved lysine for the treatment of cold sores.
2) No professional organization has stepped forward and made a recommendation in regards to this treatment approach or an appropriate dosing level (like the American dental Association has with fluoride supplements).
Dosing: If you're considering taking lysine supplements, be smart about it.
In the studies mentioned above, the most common dosing of lysine (L-lysine monohydrochloride) lay in the range of 1000 to 1200 mg per day, typically broken up into two or three individual doses taken throughout the day. One study, however, utilized a significantly higher daily dose.
While you may decide that L-lysine fever blister therapy is an approach you would like to try, let us remind you that it's best that supplements are only taken in response to a recommendation by your health care professional. Contraindications associated with a person's current health status (including renal and hepatic disease) exist. As do the potential for side effects and interactions with other medications.
An alternative treatment approach based on the same arginine / lysine theory.
In lieu of taking lysine supplements, a person might take the approach where they adjust their diet and reduce their intake of foods that are comparatively high in arginine content during those time frames when they are most likely to experience a fever blister outbreak. Nuts, seeds and some types of beans (peanuts, almonds, sunflower seed kernels, walnuts, hazelnuts, lentils, Brazil nuts, cashews, pistachios, flax seeds, kidney beans, soy beans) are especially rich in arginine content and could be easily avoided or substituted during at-risk times.
Has there been any recent lysine research?
We found it interesting that our PubMed search only identified one lysine / cold sore clinical research study having been published in the entire last decade. This was a manufacturer-sponsored study (Singh BB, et. al., 2005) that evaluated the use of a cream (SuperLysine Plus+) that contained lysine (as well as other compounds). [Note, this product is not an oral dietary supplement as we have discussed previously on this page.]
The conclusions of the study were favorable for the cream, suggesting that it sped up cold sore healing times. We will state, however, that this was not a "blind" study and there was no placebo treatment involved. Rather it was a simple evaluation of the course of healing of cold sores after the use of this one type of cream had been initiated. We'll also state that this study appears not to have spawned any published follow-up studies (by January 2011), even by the original authors, that might confirm its findings under more stringent research conditions.