L-tryptophan is a versatile essential amino acid that the body cannot produce or can only produce in insufficient quantities. L-tryptophan is easy to replace with a balanced diet and good quality nutrients. Duck, pork, cottage cheese and eggs are all rich in L-tryptophan. If you also want to cover your L-tryptophan intake from other sources, then you should take BioTechUSA L-Tryptophan dietary supplement capsules. Thanks to its capsule form, it is easy to divide and take anywhere during the day.