Once the baby is born, oxytocin promotes lactation by moving the milk into the breast. When the baby sucks at the mother's breast, oxytocin secretion causes the milk to release so the baby can feed. At the same time, oxytocin is released into the brain to stimulate further oxytocin production. Once the baby stops feeding, the production of the hormone stops until the next feeding.
Serotonin influences sleep and sleep-wake cycles in many ways, and scientists continue to make discoveries about how this important neurochemical affects our sleeping and waking lives. One important way serotonin affects sleep and bio time is through its relationship with the “sleep hormone” melatonin. Melatonin is made from serotonin in the presence of darkness. (Remember, melatonin production in the body is triggered by darkness and suppressed by exposure to natural and artificial light.) Healthy serotonin levels are essential for maintaining healthy melatonin levels—and both serotonin and melatonin are critical to sleep and a well-functioning bio clock. With its ability to increase serotonin, 5-HTP supports a neurochemical process that can enable high-quality sleep and keep the body’s bio clock in sync.
We think that the most important region is the nucleus accumbens, which is kind of up here. The nucleus accumbens is where we can measure a release of the neurotransmitter dopamine when humans or animals take drugs or are exposed to other rewarding stimuli, such as sex. Or gambling, for example, or monetary reward activates the nucleus accumbens as well.
Potential side effects of 5-HTP include heartburn, stomach pain, nausea, vomiting, diarrhea, drowsiness, sexual problems, vivid dreams or nightmares, and muscle problems. Because 5-HTP has not been thoroughly studied in a clinical setting, possible side effects and interactions with other drugs are not well known. According to the US National Institute of Health TOXNET, 5-HTP has not been associated with serotonin syndrome or any serious adverse events in humans. Across multiple studies, 5-HTP also been reported to not cause any noticeable hematological or cardiovascular changes. 5-HTP also has not been associated with eosinophilia.