5-HTP and Serotonin
5-Hydroxytryptophan (5-HTP) is produced in the body from the essential amino acid L-tryptophan. It is converted to the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). Taking 5-HTP as a supplement increases the production of serotonin. Serotonin in the body helps to make one feel relaxed, happy, and confident. It also has many other uses such as appetite control, mood and behaviour regulator, cardiovascular function, sleep, muscle contraction, endocrinal secretions’ regulation, memory and learning, temperature regulation, etc. Although 5-HTP is not found in food, amino acid tryptophan from foods such as chicken, turkey or milk can be utilized by our body to make 5-HTP.
Serotonin and Feelings of Well-Being
Serotonin, at an appropriate level, can help promote feelings of comfort and well-being. According to information provided by Dr. Charles Grisham and Dr. Reginald Garrett, the brain makes serotonin when it is signaled. One signal is carbohydrate consumption. This is why there is a feeling of being happy and content after eating foods that contain sugar such as a sugary or starchy snack. For this reason, patients who suffer from depression is prescribed prescription that helps the brain synthetically elevate serotonin levels, such as 5-HTP medication, which could relieve depression symptoms.
Serotonin and Sleepiness
Serotonin is a chemical precursor for melatonin, the hormone which is used to reduce jet lag, adjust sleep-wake cycle, and as a sleep aid. Serotonin can facilitate either the wakefulness or sleepiness. When serotonin level is low, the body increases the level of excitatory neurotransmitter as a compensative mechanism, disrupting sleep-wake cycle. In one study, participants who consumed 5-HTP could sleep quicker and deeper when compared to placebo. Another study in the journal “Sleep” notes that a deficiency or malfunctioning serotonin transporters in the brain increase the risk of insomnia. In fact, 5-HTP may be as effective as certain antidepressant drugs, with fewer side effects.

Chemically speaking, the link between 5-HTP and sleep go one step deeper. Assuming that 5-HTP is derived from protein rich food, here is a pathway that leads from Tryptophan to Melatonin.
Protein -> Tryptophan -> 5-HTP -> Serotonin -> N Acetyl Serotonin -> Melatonin: The resulting melatonin is the hormone that helps us sleep quicker and deeper.

1. Nicolodi M and Sicuteri F. Fibromyalgia and migraine, two faces of the same mechanism. Serotonin as the common clue for pathogenesis and therapy. Adv Exp Med Biol 1996;398:373-379.
2. Poldinger W, Calanchini B, and Schwarz W. A functional-dimensional approach to depression: serotonin deficiency as a target syndrome in a comparison of 5-hydroxytryptophan and fluvoxamine. Psychopathology 1991;24(2):53-81. 
3. Zmilacher K, Battlegay R, and Gastpar M. L-5-hydroxytryptophan alone and in combination with a peripheral decarboxylase inhibitor in the treatment of depression. Neuropsychobiology 1988;20(1):28-35. 
4. Angst J, Woggon B, and Schoepf J. The treatment of depression with L-5-hydroxytryptophan versus imipramine. Result of two open and one double-blind study. Arch Psychiatr Nervenkr 1997;224:175-86.