How does Lysine prevent canker sores?

[Thin Lizzy]

How does it work?

[EarthStone777]

IANA Doctor nor a Nutritionist, but what I was told during the 5 years I worked at a health food store and sold Lysine to customers (and thus what I told those customers about it)...

...was that canker sores could be caused by various things. One of those things was a deficiency of Lysine and thus taking it as a suplement could possibly prevent them.

I don't know if that's true, and I'm hoping that one of the Doper Doctors or other informed fellow will reply with a more sure answer.

[GaryM]

I have no cite to back this up, but when I feel as though I'm going to get a cold sore, I take about 5, 1000Mg. tablets of Lysine a day. I usually don't have a cold sore develop. If it does, it's usually gone in a day or two.

FWIW, that's my personal experience. YMMV

[choosybeggar]

ChoosyDermMD signing in.

I'm not aware of the use of lysine in canker sores (technical name is aphthous ulcers). The literature I'm familiar with deals with cold sores.

An excellent summary of the use of lysine (an amino acid found in abundance in the normal western diet) to control herpes labialis (cold sores) can be found at Am J Health Syst Pharm. 2001 Feb 15;58(4):298-300, 304. It requires a subscription, and is a pdf so I'll summarize.

There are no good, large studies demonstrating the effectiveness of lysine in herpes. There are several, small, sorta half-assed studies showing that lysine decreases the frequency of herpes ourbreaks but not the severity or duration of outbreaks. Additionally, lysine is believed to be safe up to doses of 3 grams per day but caution is advised in kidney and liver disease as well as in pregnancy or in lactating mothers. Since it's safe and possibly effective, I have no problem with my patients using it.

The putative mechanism (if you believe it works) lies in the fact that herpes simplex virus (HSV) is highly dependent on high levels of intracellular arginine (another amino acid) for replication. Lysine may act as a competitor with arginine and block replication.

[vetbridge]

Originally Posted by choosybeggar

The putative mechanism (if you believe it works) lies in the fact that herpes simplex virus (HSV) is highly dependent on high levels of intracellular arginine (another amino acid) for replication. Lysine may act as a competitor with arginine and block replication.

Felines get ocular infections involving a herpes virus. There are some good studies that show decreased frequency and severity of outbreaks in cats dosed daily with Lysine. The mechanism you state is what I have heard also. In the veterinary community it is well accepted as effective.

One brand of lysine sold for use in cats is Enisyl. I dispensed the product for over a year before I realized that the name was just lysine spelled backwards!

[Malice]

Can't speak to prevention, but this explains a little about the sores and their treatment. Lysine doesn't appear to be a major player, FWIW.

From USC Health magazine:

"Charles Shuler, D.M.D., Ph.D., the George and Mary Lou Boone Chair in Craniofacial Molecular Biology and associate professor at the USC School of Dentistry, says that although the precise reason the sores appear is unknown, they appear to arise when the body’s own immune system misfires in a localized area and begins attacking normal tissue.

Many people find relief from the pain using over-the-counter remedies that either numb the nerve tissue that the sore exposes or provides a physical barrier to protect the nerves.

While these products ease the symptoms, they do not actually speed the healing process.

Shuler jokes that patients are sometimes told that 'without treatment the sore will heal in seven to 14 days, and with treatment, they will heal in one to two weeks.'"