Lysine is an essential amino acid, meaning you need it but your body can't make it. You need lysine for forming collagen and connective tissue, absorbing calcium and converting fats into energy. Regularly taking lysine may also limit outbreaks of genital herpes and cold sores, according to the University of Maryland Medical Center. The Institute of Medicine recommends you get at least 51 milligrams of lysine for each gram of protein in the food you eat.
Meat and Poultry
Beef is one of the best sources of lysine. For example, a 3-ounce serving of select top round beef roast with the fat trimmed off will provide you with 3.1 grams of lysine. Other types of meat and poultry are also among the better sources of lysine. The same amount of rotisserie chicken breast meat provides 2.8 grams of lysine, and braised top round veal contains 2.6 grams per 3-ounce serving. Braised lamb leg or shoulder has about 2.5 grams of lysine per 3-ounce serving, and the same-size serving of roasted turkey breast contains 2.4 grams.
Fish and Seafood
Seafood is almost as good a source of lysine as meat or poultry. A 3-ounce serving of bluefin tuna and an Alaska king crab leg each contain 2.3 grams of lysine, and 3 ounces of sockeye salmon or canned tuna provide about 2.1 grams. Other good seafood options include snapper, king mackerel, halibut and spiny lobster, which all provide about 2 grams of lysine per 3-ounce serving.
Beans and Peas
Beans and peas are among the better vegetarian sources of lysine, but they contain quite a bit less of this amino acid than most meats. A cup of canned great northern beans, adzuki beans or white beans has 1.3 grams of lysine, and so does a 1/2-cup serving of firm tofu. Lentils contain 1.2 grams of lysine per cup, as do chickpeas, split peas and edamame.
Some dairy products also provide significant amounts of lysine. A 1/2-cup serving of whole-milk ricotta cheese has 1.7 grams of lysine, and a cup of nonfat cottage cheese provides 1.3 grams. An ounce of Parmesan cheese has 0.9 gram of lysine, as does a 6-ounce container of plain skim-milk yogurt.