Learn About Lysine Health Benefits (9 min.)

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Lysine (also called L-Lysine) is one of the nine essential amino acids and a building block for protein. Since the body cannot produce lysine independently, it must be obtained through diet or supplementation. Many people consider lysine supplements to support calcium absorption, collagen formation, building muscle protein, surgery recovery, and anxiety reduction.†

While lysine is widely recognized for its potential benefits, it’s also important to understand where to get lysine from food, how much is needed, and common questions about supplementation. Below, we explore top dietary sources of lysine, daily requirements, five health benefits of lysine and vitamin C, and frequently asked questions about this essential amino acid.

How Much Lysine Do You Need?

The recommended dietary allowance (RDA) for adults 19 and older is 38 milligrams per kilogram, or 0.017 grams per pound of body weight per day. So, an adult who weighs 120 pounds will need approximately 2,000 mg of lysine daily, while one who weighs 180 pounds will need approximately 3,000 mg daily. Because lysine plays a role in protein synthesis and muscle building, athletes may require higher levels of lysine to aid in muscle recovery and repair.†

Top Food Sources of Lysine

Lysine is found primarily in protein-rich foods, particularly animal products. However, plant-based sources also contain lysine, making it accessible to individuals with various dietary preferences.

Animal-Based Sources

• Meat—Beef, pork, and lamb are excellent sources of lysine, typically containing approximately 3,200 mg of lysine in a four-ounce serving.
• Poultry—Chicken and turkey provide high amounts of lysine per serving. A four-ounce chicken breast has approximately 2,440 mg of lysine.
• Fish—Fatty fish such as tuna and salmon are rich in lysine and offer additional health benefits. Four ounces of cooked tuna has approximately 2,700 mg, while four ounces of salmon contain approximately 2,600 mg.
• Dairy Products—Milk, cheese, and yogurt contain significant amounts of lysine. In general, full-fat, low-fat, and fat-free versions of dairy contain similar lysine levels because lysine is found in the protein portion of the food, not the fat. One-half cup of milk contains approximately 300 mg, while four ounces of cottage cheese or Greek yogurt contains approximately 900 mg and 1,300 mg of lysine respectively.  The amount of lysine in cheese varies by type, with one-ounce of mozzarella containing approximately 700 mg. One-ounce of Swiss cheese has around 800 mg, cheddar has around 850 mg, and Parmesan has almost 1,200 mg lysine.
• Eggs—A well-rounded protein source that naturally includes lysine, two large eggs provide approximately 900 mg of lysine.

Plant-Based Sources

• Legumes—Lentils, chickpeas, and black beans contain lysine, though in lower amounts than animal sources. One-half cup of lentils contains approximately 625 mg, while the same amount of chickpeas has about 525 mg, and black beans have approximately 550 mg.
• Soy Products—Tofu, tempeh, and soy milk provide a good lysine boost for vegetarians and vegans. Eight ounces of soy milk have around 550 mg of lysine, and four ounces of tofu or tempeh contain approximately 2,200 mg or 2,300 mg, respectively.
• Quinoa—A complete plant-based protein with all nine essential amino acids, including lysine. A half-cup of quinoa has approximately 225 mg of lysine.
• Nuts and Seeds—While all nuts contain lysine in varying amounts, not all seeds contain lysine. Pumpkin seeds and pistachio nuts have moderate amounts of lysine. For example, one ounce of pistachios has about 280 mg of lysine, while one ounce of pumpkin seeds has approximately 350 mg of lysine.
• Vegetables—Potatoes, avocados, and spinach contain lysine in smaller amounts than protein-dense foods. One cup of cooked spinach or one medium baked potato has about 250 mg of lysine. A medium avocado is around 150 mg of lysine.

5 Health Benefits of L-Lysine and Vitamin C

Researchers have studied the impact of lysine on various conditions, including stress, strength enhancement,  cold sores, and more. Most studies involving lysine have been small, but here is some of the research and five health benefits of lysine and vitamin C.

1. Prevents Cold Sores

Cold sore or fever blisters often appear on the lip or corners of your mouth. Not only can they cause pain or burning, but they may also make you self-conscious about your appearance.

The Herpes simplex virus (HSV-1) causes these sores. Infections are common, with an estimated 90 percent of American adults exposed to HSV-1. HSV-1 is the leading cause of herpes infections on the lips and mouth. In some people, the virus is dormant, while others suffer from repeated flare-ups. Some studies suggest that regular use of lysine can help prevent flare-ups of cold sores and herpes.† Others showed no benefit, possibly due to the amount of lysine administered daily in each study.

In a double-blind, placebo-controlled study of 52 participants with a history of HSV-1 flare-ups, the treatment group received 3000 milligrams (mg) of lysine daily for six months. Compared to the control group, the treatment group experienced an average of 2.4 fewer HSV-1 flare-ups than the placebo group. Also, the Lysine group’s flare-ups were significantly less severe and healed more quickly.† While this study used 3000 mg of lysine per day, in general, the studies that had subjects take a minimum of 1000 mg per day had positive results.† (Note: there are no studies that support taking lysine intermittently when an eruption occurs.)

Aphthous ulcers, or canker sores, are painful open sores in the mouth. Causes of mouth ulcers include a viral infection, stress, hormonal changes, or food allergies. About 10 percent of our population regularly suffers from canker sores, and women seem to have them more often than men. A small study suggests that 500 mg of Lysine daily works well for ulcer prevention, with 1000 mg daily used for treatment.†

Individuals who suffer from canker sores or herpes outbreaks may find the supplement lysine helpful in supporting† overall wellness.†

Cooper Complete L-Lysine Supplement contains 1500 mg lysine per 3 capsules.

2. Reduces Anxiety

The Anxiety and Depression Association of America reports anxiety affects over 40 million adults. This makes it the most common mental illness in the US. Research shows that one of the health benefits of lysine may be to support a healthy stress response† by influencing cortisol levels and feelings of anxiety.† A small study found supplementing with 2.64 grams (2640 mg) of lysine and L-arginine, another amino acid, lowered stress-induced anxiety and reduced cortisol levels. This was true for those experiencing chronic stress-induced anxiety and those with trait anxiety.† Lysine may also improve digestive problems, such as diarrhea, triggered by stress.†

A deficiency of lysine interferes with the regular release of serotonin, increasing stress-induced anxiety. Serotonin regulates sleep, appetite, and mood. Low levels of serotonin are associated with depression.†

Vitamin C is well known for its immune health, but did you know it plays a role in anxiety, stress, fatigue, mood, and overall wellness?† A small study of 42 high school students showed that students who received 500 mg/day of vitamin C had reduced anxiety.† In addition, several studies showed that vitamin C supplementation has an antidepressant effect and improves mood.†

Cooper Complete Natural Vitamin C contains 850 mg of vitamin C (as calcium and magnesium ascorbates) plus 100 mg of citrus bioflavonoids per tablet.

3. Improves Calcium Absorption and Retention

We know that calcium deficiency contributes to bone loss as we age. The health benefits of lysine go beyond protecting our bones by helping control where calcium is transported in the body.† Supplementing lysine with calcium appears to enhance calcium absorption in the intestine and reduce the amount of calcium lost in the urine.† Studies in rats have shown that lysine prevents arteries from calcifying.† However, further studies (especially in people) are needed before recommending lysine to prevent blocked arteries.

As you may have guessed by seeing calcium-fortified orange juice, vitamin C helps increase calcium absorption.† And its’ role in producing collagen makes it essential to repair and maintain your bones.† A 2019 study showed Vitamin C could inhibit osteoporosis by promoting osteoblast (bone-forming cells) formation.† This suggests vitamin C improves bone regeneration.†

4. Creates Collagen to Help Heal Wounds

Whether trying to heal a surgical wound or experiencing poor healing due to other health issues like diabetes, lysine and vitamin C may help.† Lysine is required for collagen formation and helps support skin and bones.† In animal studies, lysine is more active at the wound site and speeds up the repair process.†

(Cooper Complete has a powdered collagen supplement that contains three clinically studied and patented Type I and Type II collagen peptides and can be added to drinks or foods for ease of taking.)

5. May Increase Muscle Mass

Muscle loss begins to decrease as early as age 30, with a 3-5 percent loss each decade, but that doesn’t mean you can’t take steps to prevent it. A challenging resistance training program can help, as does getting enough protein. Lysine promotes muscle fiber enlargement by increasing protein synthesis.† It also activates satellite cells, the precursors to muscle cells.†

Did you know muscle contains two-thirds of our body’s vitamin C? Vitamin C helps make carnitine, a substance that processes dietary fat and provides energy for muscles to function. Additionally, vitamin C’s antioxidant properties help oppose free radicals.† Left unopposed, these free radicals can contribute to the destruction of muscle.

Data analyzed from over 13000 European men and women found that the more dietary vitamin C middle-aged and older adults consumed, the greater their muscle mass.† With only 6 percent of US adults meeting fruit and vegetable daily intake recommendations, supplementing with vitamin C may be necessary.

Due to the functions lysine supports in the body, researchers are exploring additional health benefits of lysine. Current research includes studying lysine’s potential effects on blood pressure, diabetes, and cancer cell growth.

FAQ: Lysine Supplements

Can you get enough lysine from the diet alone?

Most adults who regularly eat animal-based protein sources get enough lysine through their diet. However, vegans, vegetarians, those who eat a predominantly plant diet, or those with specific health conditions may benefit from lysine supplementation.

Is it possible to consume too much lysine, through food or supplements?

While the body needs lysine, high doses have caused gallstones and elevated cholesterol levels in animal studies. If you have high cholesterol, heart disease, high triglycerides, or kidney disease, talk with your physician before taking lysine supplements.

Are there any side effects of lysine supplements?

Lysine supplements are generally considered safe when taken at recommended doses. However, high doses may cause gastrointestinal discomfort, such as nausea or diarrhea.

When is the best time to take a lysine supplement?

Lysine supplements can be taken with or without food, though some people prefer to take them with meals to minimize potential stomach discomfort.

Can lysine supplements interact with medications?

It’s always important to consult your physician before adding any new supplement to your regimen. Your physician understands your health profile best, so talk with them about which supplements are best for you and your medical condition.

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Cooper Complete March 7, 2025