Lysine is a type of amino acid that offers several potential benefits and 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. It’s an essential amino acid because your body cannot make it, so you need to obtain it from food (1).

It’s important for normal growth and muscle turnover and used to form carnitine, a substance found in most cells of your body. What’s more, lysine helps transport fats across your cells to be burned for energy (2).

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 4 impressive health benefits of lysine.

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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 (3).

They appear as fluid-filled blisters that can cause discomfort, such as tingling, pain, and burning (3).

Cold sores are caused by the herpes simplex virus type 1 (HSV-1), which can hide in your spine. In times of stress or if your immune system is weakened, HSV-1 can trigger the development of a cold sore (3).

According to some research, lysine supplements may help prevent HSV-1 from replicating and reduce the duration of a cold sore. It’s thought that lysine blocks another amino acid called arginine, which viruses need in order to multiply (4).

However, studies have turned up mixed results on the effects of lysine on HSV-1.

For example, one review found that supplementing with less than 1 gram (g) of lysine per day was ineffective for preventing cold sores in people who were consuming enough arginine in their diet, but taking doses over 3 g per day was able to improve symptoms of cold sores (5).

Furthermore, not all studies show that lysine is effective in reducing cold sore occurrence or duration. In fact, one review found insufficient evidence to recommend it for treating cold sores (6).

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Some studies suggest that lysine may help reduce the duration and frequency of cold sores, but the evidence is inconsistent.

2. May reduce anxiety by blocking stress response receptors

Lysine may play a role in reducing anxiety.

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 (7).

Another older study in 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 (8).

Similarly, an older study 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 males with very high stress levels (9).

After 3 months, consuming the lysine-enriched flour also helped reduce cortisol levels in females (9).

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 (10).

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 (11, 12).

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Lysine may help reduce feelings of anxiety and reduce levels of the stress hormone cortisol in some people. Early research indicates that it may even help improve symptoms in people with schizophrenia.

3. May improve calcium absorption and retention

Lysine may help your body hold on to calcium (13).

It’s believed that lysine increases calcium absorption in your gut and helps your kidneys to hold on to the mineral (14, 15).

An older study in 30 females, including 15 with osteoporosis, found that supplementing with calcium and lysine reduced the loss of calcium in the urine (15).

Those given 3 g of calcium alone had a progressive increase in calcium in their urine. However, those who also received 400 milligrams (mg) of lysine lost less calcium through their urine (15).

Lysine appears to protect your bones and may also play a part in controlling where calcium is transported in your body.

For example, it has been shown to prevent the buildup of calcium in blood vessels in rats. This kind of buildup is a risk factor for heart disease (14).

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

summary

Lysine may help you absorb more calcium and reduce the loss of calcium in your urine. It could even reduce the risk of calcium buildup in your blood vessels. However, more high quality, recent research in humans is needed.

Lysine can improve wound healing in your body.

In animal tissue, lysine becomes more active at the site of a wound and helps speed up the repair process (16).

Lysine is required for the formation of collagen, a protein that acts as a scaffold and helps support and give structure to skin and bones (17, 18).

Lysine itself may also act as a binding agent, thereby increasing the number of new cells at a wound. It may even promote the formation of new blood vessels (19).

In one 2011 study, applying a combination of lysine and hyaluronic acid topically was able to reduce the size of pressure ulcers more effectively than sodium hyaluronate, another medication used to enhance wound healing (20).

In another 2009 study in 40 rabbits, it was found that taking 21 mg per lb. (47 mg per kg) of body weight of lysine and 23 mg per lb. (50 mg per kg) of body weight of arginine significantly improved blood flow and overall bone healing (13).

In fact, rabbits that received lysine and arginine had a 2-week reduced healing time compared to the control group (13).

Wound healing is a complex process that requires different minerals, vitamins, and other factors. Lysine appears to have an invaluable role, and without adequate lysine, wound healing is impaired (21, 22).

To date, studies have only looked at oral lysine supplements on wound healing in animals, so more studies in humans are needed. Additionally, it’s unknown whether applying it directly onto wounds could be effective.

summary

Lysine is essential for the formation of collagen, an essential protein that affects wound repair. Some studies in humans and animals indicate that lysine may speed up wound healing and reduce recovery time, but research is still limited.

Lysine — like all amino acids — is used as 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:

  • Cancer: One animal study found that lysine in combination with the antioxidant catechin reduced cancer cell growth in mice (23).
  • Eye health: An older study in rats with diabetes found that lysine supplements could prevent the development of cataracts (24).
  • Diabetes: One 2009 study showed that lysine may help reduce blood sugar response in people with diabetes. However, the connection is still unclear (25).
  • Blood pressure: A study in 50 adults with lysine deficiency and high blood pressure found that lysine supplements significantly reduced blood pressure (26).

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

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Research of lysine is promising, as some evidence indicates that it may have anti-cancer effects, could help improve blood sugar levels, and may reduce blood pressure.

Lysine is found in foods that are naturally high in protein, including meat and dairy products, and also in smaller amounts in plant foods (27).

Here are some great sources of lysine (27):

  • 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 (4).

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Animal foods, such as meat, fish, and dairy supply the greatest amount of lysine, but you will also find decent amounts in legumes, nuts, and seeds. Fruits, vegetables, and grains are very poor sources of lysine.

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.