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Does Lysine Actually Help Cold Sores?

<p>Does Lysine Actually Help Cold Sores?</p>
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 5 min read

Cold sores are unpleasant, ghastly little bumps that appear on our faces ever so often. Their imminent presence is identified by a pre-tingle sensation on the lips, followed by pain and sometimes even fever. 

The sore itself is caused by a virus that has no cure. While hearing this can be alarming, it isn't cause for concern as excellent treatment options are available to manage breakouts. Lysine forms part of the treatment option list, but there is a lot of conflicting information surrounding its primary use for cold sores and its effectiveness in treating them because, after all, Lysine is just a simple amino acid. 

So here we dig deep to try and find out whether Lysine actually does help with the management of cold sores. 

Cold Sores and Lysine: The Basics 

Before we dive into the nitty gritty details of things, let's take a closer look at what cold sores are and what Lysine is. As mentioned earlier, cold sores are fluid-like blisters that form around, on, or inside the lips and mouth of individuals who have the Herpes simplex virus type 1 (HSV-1) virus. In rare cases, it may be caused by the Herpes simplex virus type 2 (HSV-2) virus. 

The herpes virus typically enters the body through breaks in the skin. It can also enter the body through mucous membranes on the lips or mouth. The virus can hide in the spine and only show up in times of stress or when the immune system is weakened. This triggers the development of cold sores. The sores are typically uncomfortable and can cause a burning or tingling sensation along with pain. 

According to the NIH (National Institute of Health), more than 60% of Americans have the HSV-1 infection. This means that treatment options are becoming more sought and researched. Since Herpes is incurable, the treatment options available are seen as management aids rather than cures. These aids ease symptoms and lessen the duration of the cold sore's stay. Lysine is 1 of 9 essential amino acids the body needs to grow and heal. 

This amino acid helps the body absorb calcium and develop collagen. It also supports the creation of the energy-producing chemical, carnitine while lowering cholesterol levels. Essential amino acids such as Lysine do not occur naturally in the body—the body doesn't produce them. The only way to get them is by taking supplements or eating foods rich in them. 

The concept of Lysine working as a remedy for cold sores comes from its ability to interfere with or stop the body's production of arginine – another amino acid that helps HSV-1 spread and grow. Studies also show that Lysine can improve wound healing. With effects like this, it's clear why this amino acid is front and center of cold sore alleviation. 

Sources Of Lysine 

We mentioned earlier that the body does not produce Lysine, and while that may be a bit shocking considering it plays such a pivotal role in body growth and repair functions, it is true. A PubMed study showed that Lysine becomes active in all possible wounds, whether it's a scrape, cut, or gaping hole. The amino acid speeds up healing and supports the repair process. 

Lab studies also showed that Lysine promotes collagen formation, and in combination with other amino acids, Lysine activates bone-building cells, promoting necessary growth as well. It's clear that Lysine is needed, so how exactly do we get it?

Lysine can be obtained from a healthy diet or supplements. The following foods can help you reach your daily intake of Lysine.

  • Eggs

  • Fish, such as sardines and cod

  • Meat and poultry such as beef and pork

  • Legumes, such as beans, peas, lentils, and peanuts

  • Soybeans, such as tofu, soybean flour, and soy protein

  • All types of cheese. The cheese with the most lysine is parmesan

Individuals can add these foods to daily meals in conjunction with the use of a cream or supplement that contains Lysine. This can increase the chances of successfully managing outbreaks of cold sores. 

How Does Lysine Work Against Cold Sores

We've established that Lysine is an amino acid that can only be sourced through external sources, but how exactly does it work, and what is its function in the bigger picture—the treatment of cold sores? 

Once Lysine is introduced into the body through topical application or oral medication, it stops the spread and multiplication of the Herpes virus. As we mentioned earlier, cold sores present themselves on/in the mouth and lips. The fluid-filled bubbles are quite sensitive and typically bust, causing the fluid to spread across a larger area of the face. 

Once this happens, the virus rapidly multiplies and infects a larger surface area. The multiplication or spread of the virus is supported by an amino acid called arginine. Arginine is found in nuts, meats, wheat, and other products. It also amplifies current outbreaks. 

Lysine slows the absorption of arginine-rich proteins into the intestine. This leaves the body with enough arginine for healthy functioning but not enough to help the virus stay active. This means that the virus will have nothing to feed off of, making the spread or replication of the virus impossible, which causes cold sores to lessen in intensity and heal faster.

In essence, Lysine makes it difficult for the virus to survive, sending it back to the spine into dormancy. Research confirms this and shows that high amounts of Lysine make the virus weak. This shortens the timeframe of an outbreak and reduces the chances of the outbreak reoccurring. 

Effectiveness and Safety of Lysine For Cold Sores

Various studies have shown that taking Lysine daily can reduce the severity and duration of cold sores. A PubMed study showed that 3g of Lysine daily for 6 months reduced the number of cold sores on the mouth and shortened the healing period. 

Another study found that the amino acid elevated the healing process of cold sores for 87% of patients, which shortened the average time of 21 days to just 6 days. The study also proved that no adverse effects were experienced. Comparable results were found in a one-year study with just 1g of Lysine daily.

While experts agree that Lysine does not completely prevent cold sores, it definitely reduces the severity of symptoms and recurrences. An NCBI review concluded that more studies are required to confirm the safety and effectiveness of Lysine in doses higher than 1.2g. 

However, the effectiveness and safety of Lysine depend not only on the amount given but also on the ratio of Lysine-to-arginine. This mainly depends on the foods in your diet. Foods such as yogurt, cheese, and goat's milk have a high Lysine-to-arginine ratio, so consuming them is beneficial. 

The above studies show that Lysine is both an effective and safe treatment option for cold sores. The treatment can be obtained in any form and carries no serious risks. 

How To Use Lysine? 

Lysine supplements are often available as a capsule, tablets, and powders. When searching for a supplement, make sure to choose a credible National Sanitation Foundation (NSF) brand with a strong consumer rating. 

Look at the ingredients label to ensure you purchase a supplement that contains 100% pure pharmaceutical grade Lysine, as this is the safest and most effective option. You can use up to 3g daily. 

Applying Lysine topically is the most effective method for treating cold sores. You must apply Lysine cream to the affected area every 2 hours for 11 days to clear up cold sores. Usually, 1g of Lysine is enough to prevent cold sores. 

Alternatively, you can use Lysine powder to make a cold sore paste. Follow the steps below:

  • Combine Lysine powder with 2 tablespoons of water 

  • Mix until you get a thick paste. You may need to add more powder

  • Apply the paste using a Q-Tip or cotton pad at night

  • Keep the leftover paste in the fridge

You can also take zinc and vitamin C supplements to give your immune system an additional boost. Adding vitamin C to Lysine use can produce favorable outcomes as vitamin c transforms Lysine into collagen. A PubMed study shows that collagen is critical in regulating wound healing phases—this effect can shorten the duration of sore breakouts and promote better healing. 

Other Uses of Lysine 

Although Lysine is most popularly known for its effectiveness against cold sore outbreaks, its benefits stretch beyond just that. Lysine is an amino acid that produces several effects that can affect different body processes. This opens up an extensive list of other uses for Lysine. Below we expand on some of them:

  • Blood Sugar Control

A study from  The American Journal of Clinical Nutrition shows high doses of Lysine help control blood sugar levels. While this is great for the body, it's also great for the healing process of cold sores as well. Research shows that regulated blood sugar levels speed up wound healing.

  • Stress and Anxiety

study found people who consumed Lysine-fortified foods for 3 months had lowered cortisol (stress-inducing hormone) levels. The evidence found that these foods reduced anxiety levels in males as well. Research shows that high anxiety and stress cause HSV-1 breakouts. So, the reduction of stress and anxiety induced by Lysine can lower the possibility of frequent or recurring cold sore outbreaks. 

  • Improves calcium absorption and retention

PubMed study showed that Lysine helps the body absorb, retain and utilize calcium more efficiently. This improves muscle, cardiovascular, and bone health. Research shows that calcium also promotes skin and wound healing, which is beneficial for cold sore outbreaks. It also regulates sebum production to keep the skin protected, healthy, hydrated, and breakout free.

Precautions and Risks 

Lysine is considered a generally safe health supplement when taken in small doses and applied topically. You can safely take up to 3g of Lysine daily without severe side effects. However, higher doses may cause the following:

  • Stomach cramps

  • Nausea

  • Diarrhea 

Lysine slows down arginine production and absorption, which is beneficial in treating cold sores. However, arginine plays an essential role in the body for wound healing, nitric oxide production, and growth. Long-term use of lysine may lead to arginine deficiency, which can cause serious health problems. 

Healthcare professionals state that long-term use of Lysine should be used/taken with caution or avoided in individuals with asthma, a compromised immune system, cardiovascular disease, or gallbladder disease. 

Lysine can increase calcium absorption, which results in weakened bones and impaired organ function. It also can increase the severity of acute renal failure. High doses of the amino acid have been shown to affect the liver as well. Therefore, caution must be taken in those with kidney and liver problems. 

Lysine must be completely avoided by individuals taking an antibiotic called aminoglycosides. These antibiotics are used for the treatment of severe infections of the stomach and urinary tract. The resulting interaction will cause kidney damage. 

Although the studies on Lysine against cold sores are strong, there is not enough evidence about the safety or negative effects of taking the amino acid during pregnancy or breastfeeding. Therefore, the use of Lysine is not recommended in these cases. If you are incorporating Lysine-rich foods into your diet, eat them in moderation. 

Other Remedies for Cold Sores

Since HSV-1 isn't curable, this means that the virus is still present in the body, and breakouts can happen at any point. Other approaches can be used to ease your symptoms if you don't have Lysine-based medicines/powder on hand or cannot use Lysine due to allergies, interactions, or contraindications. 

These approaches include:

  • Tea tree oil: Tea tree oil has anti-septic properties that can prevent further bacterial infection after blisters have popped or after the cold sore outbreak has subsided.

  • Ice or tea bags: Ice or wet tea bags—cold compresses can reduce redness and swelling. 

  • Lemon balm: Lemon balm has soothing and anti-inflammatory effects on the skin. This may reduce cold sore irritation. Studies show that lemon balm is being investigated as an effective antiviral against the HSV-1 virus.

  • Witch hazel, vanilla extract, and alcohol: These products are considered 'astringents' (drying agents) which may help dry out cold sores.

  • OTC cold sore treatments or oral prescription medication: Cold sore treatments such as Abreva help reduce the symptoms of breakouts. Prescription options such as valacyclovir or acyclovir do the same.

Besides OTC creams and oral prescription medicines, the rest of the home remedies mentioned above can also be used with Lysine-based products to speed up recovery, facilitate healing, and ease discomfort.

Another way to cope with HSV-1 or cold sore is to identify what triggers outbreaks and try to avoid those triggers. Most individuals with the virus pins stress as the number one cause of breakouts, so practicing stress reduction techniques can help promote relaxation and avoid an outbreak.

The Bottom Line 

Although Lysine has some strong evidence backing its efficacy and safety, the product is considered an alternative treatment, not a first-line one. This simply means the product is not the first recommended treatment for HSV-1 cold sores. 

Instead, other options like valacyclovir or acyclovir are prescribed. Nevertheless, this amino acid is still a force to be reckoned with and is a staple in medicine cupboards worldwide. Lysine is available as an oral supplement or a cream that can reduce the occurrence of cold sore outbreaks in less than a week when used in high doses. 



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This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.