Physical symptoms of serotonin deficiency include persistent fatigue, sleep disorders, loss of appetite combined with a craving for carbohydrates, headaches and a fluctuating body temperature, according to Progressive Health. Individuals with low serotonin levels may also experience gastrointestinal pain.
Chronic and persistent fatigue can occur in individuals with low serotonin levels regardless of the activity level of the sufferer, according to Progressive Health. While the sufferer may be quick to fall asleep, he may have difficulty remaining asleep due to increased anxiety. Weight gain can occur despite the loss of appetite as a result of the body's craving for carbohydrates typically responsible for the production of serotonin. The confluence of these digestive and gastrointestinal factors can produce increased amounts of insulin, leading to weight gain. Gastrointestinal pain typically accompanies these symptoms as a result of intestinal enterochromaffin cells being unable to secrete serotonin.
Sufferers of serotonin deficiency typically experience hot flushes, according to Progressive Health. Neurotransmitters attempting to compensate for the lack of serotonin in the hypothalamus may overreact, heating the body beyond its normal temperature. Low serotonin levels typically cause metabolic disorders that result in frequent migraines and headaches. Treatments for low serotonin include engaging in regular exercise, getting plenty of sunlight, eating carbohydrates with low glycemic indexes and taking serotonin supplements.