I think everyone would agree that it feels good to work at your highest level. You cannot always do this because you are missing essential vitamins, and minerals. One Amino Acid that is very essential is L-Tryptophan. L-Tryptophan is an amino acid, one of the building blocks of protein, but unlike some amino acids, L-Tryptophan is considered essential because the body cannot manufacture its own. L-Tryptophan plays many roles in animals and humans alike, but perhaps most importantly, it is an essential precursor to a number of neurotransmitters in the brain. As such, L-Tryptophan is the only substance that can be converted into serotonin, and therefore melatonin helping produce sleep. Taking tryptophan capsules at bed time may help not only achieve better sleep but also to enhance mood, and diminish carbohydrate cravings. We only sell  FDA registered USP Phamaceutical grade L-Tryptophan. Imagine if you lacked this essential amino acid.