Lysine
L-lysine
Supplements. Modern nutrition.
Also called Lys, Amino acid lysine
Spanish: Lisina
Check first if kidney diseaseAn essential amino acid, a building block of protein that the body cannot make, sold mainly for cold sores.
Did you know? Lysine is a building block of collagen, the protein that gives skin, tendons, and bones much of their strength.
What it may help, and how strong the proof is
- Infections. Mostly 1970s and 1980s trials show fewer cold sore outbreaks with lysine, but others show no effect. The studies are small and mixed.Early proof
- Bones. Sold to help the body absorb calcium. Most support comes from animal or small studies, not strong human trials.Traditional proof
Parts of the body
Traditional use
Lysine has no real history in folk medicine. It became a popular supplement in the late 1900s, mainly for cold sores.
How it is classified
How people take it
Cold sore studies used about 600 to 3,000 mg a day, taken for several months. One small trial hinted at benefit above 3 grams a day. Most adults get enough lysine from food.
Capsule, powder, tablet and food.
Where to get it
Best food sources are meat, poultry, fish, eggs, dairy, soy, beans, and lentils. Most lysine supplements are made by fermentation. Sold as capsules, tablets, and powders.
Be careful
Generally safe in normal food amounts. High doses can cause stomach upset and diarrhea. Kidney disease can change how the body handles amino acids, so check with a doctor first.
Avoid if: kidney disease; gallbladder disease; heart disease.
Mixing with other things
- Works well together
Vitamin C is needed to turn lysine and proline into collagen.
- Works well together
Collagen supplies building blocks such as lysine and proline, and both are used for skin and joints.
The honest take
Lysine is an essential amino acid that most people get from food, so supplements are often not needed. The best-known use is cold sores, where some small trials show fewer outbreaks while others show no effect. Claims that it helps anxiety, bones, or immunity have little or no good human proof.