answer:It is one of the 20 amino acids the body uses as building blocks for making proteins in particular seretonin. The body is not able to make it so you have to get all you need from your diet (it is an essential amino acid). It is particularly plentiful in chocolate, oats, dried dates, milk, yogurt, cottage cheese, red meat, eggs, fish, poultry, sesame, chickpeas, sunflower seeds, pumpkin seeds, spirulina, and peanuts.