Lysine: What it is and Why You Need It

Lysine is an amino acid that’s hard to get from a vegan and vegetarian diet. It’s considered essential because your body can not make it from other amino acids, so you must get it from the food that you eat.

Why You Need It

Like every other amino acid, lysine is important. Your body depends on it for growth (super important for children). It’s also needed for healthy bones, to produce energy (important for all your muscles, including the heart), and to create collagen, cartilage, and connective tissues (like skin).

Healthy Bones

Because it helps your body absorb calcium, this essential amino acid helps build and maintain strong bones. And it helps to prevent osteoporosis.

Your Body Uses it to Make Carnitine

Carnitine is a non-essential amino acid. It’s well know for heart health and as a weight loss supplement.

You can get carnitine from eating certain foods, and your body can create it from a combination of lysine and methionine.

Carnitine is critical for heart health. If you have a deficiency, it usually affects the heart first. It’s also important for energy production as it helps turn fat into energy. This is part of the reason why carnitine gets marketed as a weight loss supplement. Some studies have shown that carnitine supplements can help reduce fat (as it burns it for energy), increase muscle mass, and reduce fatigue, which can help some people lose weight.

To get more carnitine, combine foods high in lysine (eggs, quinoa, soy) with those that contain methionine (avacado, ricotta cheese, and wheat germ). You can also consume vegetarian foods that contain both, like cottage cheese and eggs.

May Help With Cold Sores and Genital Herpes

Some people find lysine supplements help lessen the severity or duration of the herpes simplex virus (HSV). There are two types of herpes virus. Herpes simplex 1 causes cold sores (blisters) around the mouth; and herpes simplex 2 causes genital herpes (the most common sexually transmitted disease).

If you choose to supplement, only do so under the guidance of a qualified doctor who can monitor your amino acid levels. Taking too much of one amino acid will cause a deficiency in another. So while you may resolve one issue, another one will develop.

What Happens if You’re Deficient in Lysine

Signs of a deficiency include the following:

  • Slow growth (again, making this amino acid even more essential for children)
  • Dizziness, nausea, and fatigue
  • Reproductive disorders
  • Anemia


  • Eric R. Braverman, M.D., The Healing Nutrients Within, (CA: Basic Health Publications, Inc. 2003)
  • University of Maryland Medical Center, L-Carnitine
  • University of Maryland Medical Center, Lysine