The concentration of melatonin in the body changes with the time of day. A typical daily value is less than 10 picograms per milliliter of blood. This corresponds to one billionth of a milligram per milliliter. At night, however, values of up to 100 pg/ml are normal for young, healthy people. As we get older, the body secretes less melatonin. In younger people, the body's own amount of melatonin increases twelvefold during the night, but in older people it only increases threefold. However, medications such as ibuprofen, cortisone derivatives or beta-blockers can also inhibit nighttime melatonin production. A (too) low melatonin level is also promoted by: tobacco, alcohol, caffeinated drinks, persistent stress and intensive exercise in the evening. Melatonin production is also disrupted in people who go to bed at very different times. Those who go to bed at 11 p.m. on Mondays and 2 a.m. on Tuesdays will not achieve the same quality of sleep as those who go to bed regularly.
A melatonin level that is too low can result in the following symptoms: difficulty falling asleep and waking up early. In the long term, the resulting reduced sleep quality can lead to problems concentrating, memory loss, mood swings and an increased susceptibility to illness.
A melatonin level that is too high also results in sleep disorders. Typical symptoms include problems getting up and a feeling of tiredness and lack of motivation that persists throughout the day. Causes of an increased melatonin level include long periods of darkness in winter, liver dysfunction, taking tryptophan and some antidepressants, and taking high doses of vitamin B3 or vitamin B6. In any case, if you are persistently tired, it is advisable to have your melatonin level checked by a doctor in order to start the right treatment.