COLD SORES? Here’s Help

Although cold sores are generally short term and benign, they can substantially impact quality of life, especially if they break out at important times, such as a wedding or a job interview, when we want to be seen at our best. Over 75% of people harbour one of the viruses that cause cold sores, although they may not be aware of it. Some people are well aware, because they have recurrent outbreaks. People who have very frequent outbreaks or ongoing lesions may be given daily drug treatment aimed at reducing the frequency and intensity of outbreaks.

Cold sores are caused by either the Herpes simplex 1 or Herpes simplex 2 virus. Those viruses are often latent, thank goodness! We can catch the virus without being aware of it until a cold sore erupts, which may occur even years later. They hide away in the nervous system, waiting for a chance to burst forth when we are depleted or stressed. 

Because the viruses hide in a particular area of the nervous system between outbreaks, and each nerve supplies a specific area of the body, cold sores will erupt in the same area each time. They usually make a sore at the edge of the lips, but some unfortunate folk get outbreaks in the genitals. Herpes simplex 1 is the virus that more often affects the mouth, and Herpes simplex 2 more often affects the genitals, but that’s not always the case: either virus can infect either location. The research quoted in this Health Post is about herpes around the mouth, not lower down.

The first time the virus erupts into a cold sore, it may come with fever and other common viral symptoms such as aches and general malaise. Outbreaks after that are more likely to be triggered by another viral illness, piggy-backing on it while you are sick, or in times of high stress or exhaustion. 

Viruses thrive on the amino acid arginine. When herpes viruses were grown in a laboratory, they could not replicate in an arginine-deficient medium. Arginine is one of the building blocks of proteins, and is found in a lot of foods. Some foods that contain relatively large proportions of arginine are chocolate, nuts, high-protein white meats (such as chicken, pork, and turkey) and legumes.

Lysine, another amino acid, is known to slow the replication of viruses. This happens, at least in part, by antagonising arginine. Lysine is an essential amino acid, which means that we can’t make it in our bodies, so we have to get it from foods and supplements. 

Research on lysine in laboratory cell cultures led to clinical trials for people with cold sores. Early studies using less than 1g of lysine daily did not show a significant effect, although there had been mixed results in studies ranging from 500mg to 1.25 grammes a day. And a 2015 Cochrane review of research (considered the “gold standard”) concluded that the only things that had a reliable effect on reducing the number of outbreaks were antiviral drugs (acyclovir, famicyclovir, or valacyclovir). However the benefit was very, very small. They also noted that the safety of these drugs in the long run wasn’t clear, so only people plagued by ongoing cold sores are usually put on these drugs for prevention.

Then a 2021 review on the effects of diet and supplements on recurrent oral cold sore, found that lysine supplementation was effective for prevention, but not for decreasing duration of active lesions. The evidence supports use at 3 g a day, as lower levels of supplementation show mixed evidence of effectiveness. Other studies found that 3g of lysine a day is a safe dose which improved people‘s subjective experience of the outbreak. It also found that the reduction in outbreaks correlated with the level of lysine found in people’s blood, and of course that can come from both diet and supplementation. Some of the trials on lysine supplementation mentioned in the reviews above paired it with a low arginine diet, while others did not.

Then we got even better news from a 2023 research review! It found 2.4 times fewer HSV outbreaks in a 6-month-long trial, and concluded that lysine is successful in reducing the recurrence of HSV infection. And not just that, it also significantly diminished symptoms and healing times compared with the placebo group.

This review concluded that, when compared to the antiviral treatment acyclovir, lysine is a safe natural compound, without reported adverse side effects, and is a promising alternative treatment option for patients with HSV. We SHINE doctors are delighted to see more and more research into the healing benefits of natural substances, and can’t help but feel validated when their performance equals or outdoes drugs, often with fewer side-effects.

If you are feeling tired and susceptible to a cold sore outbreak, or you have a cold sore and don’t want your diet to support it, the internet can tell you which foods are high in arginine, so you can try to avoid them. Although we haven’t been able to find any human studies on diet alone, it makes sense not to feed these viruses with what they need to reproduce. We have met many patients who notice that eating chocolate and nuts tends to trigger their cold sores.

Lysine is a readily available, inexpensive supplement in most health food stores. It may be necessary to use lysine as a supplement, in order to achieve a therapeutic dose. Amino acids can be taken anytime, with a meal or between meals.

There are natural topical treatments proven to help heal cold sores:

A study in 2008 found that silica gel was as effective as topical 5% acyclovir cream in treating cold sores, and it took effect more quickly and was well tolerated.

More recently, a 2025 Cochrane review concluded that “topical herbs are promising and effective”. It reviewed 346 articles and 7 randomised controlled trials involving 1250 patients, and found that applying the following natural herbs, topically, benefitted cold sore sufferers, without causing adverse side effects:

• Melissa officinalis (Lemon balm) leaf extract cream consistently reduced pain and swelling, and decreased lesion size compared to placebo or acyclovir

• Olea europaea (Olive) leaf cream triggered faster symptom improvement, and faster healing compared to acyclovir

• Propolis shortened the time to encrustation and complete healing compared to acyclovir

• Salvia officinalis + Rhuem palmatum + Rheum officinale (Sage and Rhubarb) combined in a cream were comparable to acyclovir in mean healing time

Because arginine is essential for growth, wound healing and other important biochemical functions, there are some conditions where it is not recommended to reduce arginine and increase lysine. This is especially important if you suffer from kidney or small bowel disease, sepsis, sickle cell disease, or have recently experienced significant burns, trauma, or surgery. Consult your health care provider for individualized advice.