Lysine, or L-lysine, is one of the nine essential amino acids required for growth and tissue repair in humans. Lysine’s main function is to aid in the production of Carnitine, a nutrient responsible for converting fatty acids into energy and helping lower cholesterol. Lysine also plays a role in calcium absorption and in the formation of collagen which is necessary for the production of skin, tendons, and cartilage. Although Lysine is necessary to maintain good health, we cannot produce our own Lysine. We obtain Lysine and the other eight essential amino acids through our regular diets or supplements.
The majority of us are able to get enough Lysine through a well-balanced diet. The recommended daily intake of Lysine depends on a person’s age and weight:
Age | Lysine Requirements: mgs/kg/day |
Infants, < 4 months | 103 |
Children < 10 years | 64 |
Children 10 – 12 years | 44 |
Adults | 12 |
When considering your Lysine requirements, it’s important to note that there may be different daily recommendations depending on your age. Studies on requirements for individual essential amino acids in older adults are inconsistent. Some say that Lysine requirements are higher in the elderly, others indicate that they are lower, and others indicate that they remain the same.2 The majority of people have a diet sufficient in Lysine and do not need a daily Lysine supplement. Before considering adding a Lysine supplement to your daily regimen, be sure to consult with your health care provider for the recommended dose.
If you do decide that additional Lysine in your diet would benefit your health, there are a number of protein-rich foods that are excellent sources. Any type of meat will be rich in Lysine, particularly red meat, pork, and poultry. Cheese, yogurt, and other dairy products are good options for vegetarians, while vegans can supplement their Lysine requirements through beans and other legumes.
While most people do not need to supplement their diet with additional Lysine, those with higher metabolic activity, such as athletes, or those with higher needs regarding tissue regeneration, such as burn patients, may need higher amounts. Lysine supplements are available through most pharmacies and health stores. If you do not have enough Lysine in your diet, you may experience symptoms like:
- Fatigue
- Nausea
- Dizziness
- Loss of appetite
- Agitation
- Bloodshot eyes
- Slow growth
- Anemia
- Reproductive disorders
Although everyone needs a minimum daily amount of Lysine, a diet high in Lysine may be useful in the treatment of certain medical conditions including Herpes and Osteoporosis. The research on whether Lysine helps prevent outbreaks of genital and oral Herpes is somewhat inconclusive when considered as a whole. Some studies suggest that taking Lysine may help prevent outbreaks, while others show no improvement. Lysine has an antiviral effect on the Herpes Simplex Virus (HSV) by blocking the activity of another amino acid, Arginine, which is responsible for the replication of the virus. Most experts agree that Lysine does not help with the healing of herpes outbreaks, but that supplementation may reduce recurrences or improve symptoms.
While Lysine’s ability to block Arginine may assist in Herpes outbreaks, when Lysine is combined with Arginine it can be useful in the treatment of Osteoporosis. Lysine ability to promote the absorption of calcium, while reducing calcium loss in the body, can be useful to help people suffering from Osteoporosis. Studies suggest that the combination of Lysine and Arginine stimulates bone-building cells and enhances the production of collagen which combats bone loss in those with Osteoporosis. There have not yet been any studies to examine whether Lysine can help prevent occurrences of Osteoporosis.
As an essential amino acid that we cannot produce ourselves, it’s important to ensure that you’re getting enough Lysine in your diet. Most people who eat a well-balanced diet will get sufficient Lysine from foods and will not need to take a supplement. However, if you are a very active athlete, carry the HSV, or have Osteoporosis, you should talk to your physician about Lysine supplements. Before taking any new supplement, be sure to do your own research and also consult your physician or health care professional about the potential side effects, medication interactions, and effect on other medical conditions you might have.