Lysine

Lysine — an essential amino acid necessary for the normal functioning of the body. It participates in the synthesis of proteins, hormones, enzymes, and collagen, aids in calcium absorption, and supports the immune system.

Since the body cannot synthesize lysine on its own, it must be obtained from food. A deficiency or excess of lysine can lead to a number of physiological disorders, so it is important to maintain a balance in its consumption and consider the individual needs of the body.

Beneficial Properties

Lysine performs many functions in the body:

• participates in the synthesis of structural and enzymatic proteins;
• necessary for the formation of collagen, ensuring the health of skin, ligaments, and blood vessels;
• promotes calcium absorption and strengthens bones and teeth;
• supports the immune system by stimulating antibody production;
• helps the body cope with viruses, including reducing the manifestations of herpes.

Daily Requirement and Sources

The recommended daily dose of lysine:

• adults — about 30 mg per kg of body weight;
• children and adolescents — 40–50 mg per kg of body weight;
• athletes and people with high loads — up to 50 mg per kg of body weight.

Main sources of lysine:

• meat (beef, chicken, pork);
• fish and seafood;
• dairy products (cheese, cottage cheese, yogurt);
• eggs;
• legumes (lentils, beans, soy);
• nuts and seeds.

Plant sources may contain less lysine, so vegetarians and vegans should pay special attention to the diversity of proteins in their diet.

Possible forms and their absorption

Nutrient forms are listed from best to worst:

L-lysine. Biologically active and the most bioavailable form, it participates in the synthesis of collagen, enzymes, antibodies, and calcium absorption. It is used to strengthen immunity, prevent herpes, and restore tissues.

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iHerb

Amazing Nutrition, L-Lysine, 1,000 mg, 360 Tablets

≈ $35.50

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iHerb

21st Century, L-Lysine, 1,000 mg, 90 Tablets

≈ $6.21

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iHerb

Nature's Craft, L-Lysine, 1,000 mg, 100 Tablets (500 mg Per Capsule)

≈ $8.72

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iHerb

Nutricost, L-Lysine, 1,000 mg, 250 Capsules (500 mg per Capsule)

≈ $13.47

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iHerb

Nutricost, L-Lysine, 1,000 mg, 500 Capsules (500 mg per Capsule)

≈ $18.12

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iHerb

NOW Foods, L-Lysine, 500 mg, 100 Tablets

≈ $6.68

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iHerb

NOW Foods, L-Lysine, 500 mg, 250 Tablets

≈ $15.83

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iHerb

NOW Foods, L-Lysine, 500 mg, 250 Veg Capsules

≈ $17.78

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iHerb

Swanson, L-Lysine, 500 mg, 100 Capsules

≈ $7.22

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iHerb

Swanson, L-Lysine, 500 mg, 300 Capsules

≈ $17.10

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L-lysine HCl (hydrochloride). Lysine salt with good stability and bioavailability is often used in supplements. It has the same effects as pure L-lysine but may be slightly more irritating to the gastrointestinal tract.

D-lysine. Inactive in the human body and not used in metabolism. Not used in supplements.

Symptoms and Consequences of Deficiency

Lysine deficiency can cause the following disorders:

• reduced immune defense and frequent infections;
• fatigue, muscle weakness, and loss of muscle mass;
• stunted growth in children;
• worsening skin condition and slow wound healing;
• impaired calcium absorption and decreased bone density;
• increased anxiety, irritability, and decreased appetite.

In cases of prolonged deficiency, anemia and osteoporosis may develop.

Possible Risks of Excess and Their Manifestations

Although lysine is not considered toxic, its excess can cause:

• digestive disorders (nausea, bloating, diarrhea);
• imbalance of other amino acids (e.g., decreased arginine levels);
• increased load on the kidneys, especially in the presence of chronic diseases;
• possible allergic reactions (itching, rash);
• in rare cases — headaches and mood changes.

The threshold for excess varies individually, but consuming more than 5 g of lysine per day without medical necessity may increase the risk of side effects.