Lysine is an amino acid that is found mostly in animal products. Though more research is needed, it may help reduce anxiety, prevent cold sores, improve calcium absorption, and promote wound healing.

Lysine is a building block for protein and an essential amino acid. Because your body cannot make it, you need to obtain it from food. You need lysine for:

  • growth
  • muscle turnover
  • forming carnitine, a substance found in most cells of your body
  • transporting fats across your cells to be burned for energy

L-lysine is the form of lysine your body can utilize. It’s naturally found in food and is the type used in supplements.

Here are four impressive health benefits of lysine.

1. May protect against and treat cold sores by blocking arginine

Cold sores, or fever blisters, are symptoms of an infection, often appearing on the lip or the corners of your mouth as fluid-filled blisters that can cause discomfort, such as tingling, pain, and burning.

Cold sores are caused by the herpes simplex virus type 1 (HSV-1), which can hide nerve cells near the base of your brain. In times of stress or if your immune system is weakened, HSV-1 can trigger the development of a cold sore.

One 2020 review of research suggests lysine supplements may help prevent HSV-1 from replicating and reduce the duration of a cold sore. Lysine may block another amino acid called arginine, which viruses need to multiply.

One review found that supplementing with less than 1 gram (g) of lysine per day was not effective in preventing cold sores in people consuming enough arginine in their diet. However, the authors suggest that doses of over 3 g per day could improve the symptoms of cold sores.

However, not all studies show that lysine is effective in reducing cold sore occurrence or duration. One 2015 review found insufficient evidence to recommend it for treating cold sores.

Lysine may play a role in reducing anxiety, though more research is still needed to support this.

One 2003 study found that it blocked receptors involved in stress response. Researchers observed that rats given lysine had reduced rates of stress-induced loose bowel movements.

A 2004 study by the same researcher found that adding 4.2 g of lysine to each kilogram (kg), or 2.2 pounds (lbs.) of wheat flour in villages in Syria helped reduce anxiety scores in male participants with very high stress levels. After 3 months, consuming the lysine-enriched flour also helped reduce cortisol levels in female participants.

Similarly, the same researcher’s 2007 study of 50 people showed that supplementing with 2.64 g of lysine and arginine lowered stress-induced anxiety and reduced levels of the stress hormone cortisol after 1 week.

One 2022 study in animals suggests lysine may decrease anxiety.

Lysine may also be able to help people with schizophrenia, a mental disorder that disrupts an individual’s perception of the outside world, resulting in changes in thought and behavior.

Though research is still in its early stages and is limited to mostly older studies, lysine may have the potential to improve schizophrenia symptoms in combination with prescribed medication.

Lysine may help your body hold on to calcium by increasing calcium absorption in your gut and helping your kidneys hold on to the mineral.

One 2018 study in people with osteopenia found that the relative bioavailability of oral calcium lysinate was 223.15%, which suggests calcium lysinate may have a benefit as a dietary supplement.

Your body needs calcium to keep your bones strong, especially as you age.

A 2022 review of research suggests that essential amino acids, including lysine, have a positive effect on bone health in aging adults.

Still, more high quality, recent research is needed before lysine supplementation can be recommended to support bone or heart health.

Lysine can improve wound healing in your body. It helps you form collagen, a protein that acts as a scaffold and supports and gives structure to skin and bones.

Lysine may also act as a binding agent, increasing the number of new cells in a wound.

In a small 2023 study, researchers used a 15% lysine cream twice daily to treat diabetic foot ulcers and found that it helped wounds close and heal more quickly than standard treatment or a placebo. The researchers noted there may be a benefit to using it along with standard treatment.

Wound healing is a complex process that requires different minerals, vitamins, and other factors. Lysine appears to have an invaluable role and wound healing is impaired without adequate lysine.

Studies have only looked at oral lysine supplements on wound healing in animals, so more studies in humans are needed.

Like all amino acids, Lysine is a building block for protein in your body. These proteins help produce hormones, immune cells, and enzymes.

Lysine may have several benefits in addition to those discussed earlier.

Here are other areas where lysine may benefit your health:

Adequate lysine is essential for maintaining your health, and lysine supplements may benefit certain people and conditions.

Lysine is found in foods naturally high in protein, including meat and dairy products, and in smaller amounts in plant foods.

Food sources of lysine include:

  • Meat: beef, chicken, and lamb
  • Seafood: mussels, prawns, and oysters
  • Fish: salmon, cod, and tuna
  • Dairy products: milk, cheese, and yogurt
  • Legumes: soy, kidney beans, and chickpeas
  • Nuts and seeds: pistachios, pumpkin seeds, and cashews

If you’re prone to cold sores, taking 1 g of lysine daily or using a lysine-containing gel may be worth a try, but remember that it’s best to speak to a healthcare professional first.

Is lysine an anti-inflammatory?

Lysine is an essential amino acid that may have some anti-inflammatory properties.

What should I avoid when taking lysine?

As lysine increases how much calcium is absorbed in the body, it’s best to avoid taking too much calcium along with lysine.

Does lysine make you gain weight?

More research is needed to determine the relationship between lysine supplementation and body weight.

Lysine is an essential amino acid with many benefits that range from preventing cold sores to reducing anxiety and promoting wound healing.

As a building block of proteins, it may also have numerous other benefits. Without enough lysine, your body may be unable to produce sufficient or appropriate hormones and immune cells.

Lysine is found in high amounts in animal products, including meat, fish, and dairy. Certain types of legumes, nuts, and seeds can also help increase your intake.