Dosage and Possible Side Effects
Currently there are still no uniform dosage guidelines according to which melatonin should be administered related to the different indications. Different clinical studies used a dosage range from 0.5 mg or less up to 25 mg or more, which makes the comparison of results difficult. Additionally, different formulations were also used, such as quick-releasing or chronobiologically-combined/pulsing melatonin, so that a comparison is not clear here, either. However, if all the collected data to date is summarized, then the following dosage recommendations can be seen as suitable: Under so-called chronotherapy, which helps to reset the inner clock, dosage amounts of 0.5 mg to 1 mg of a fast-releasing formulation are sufficient. A pulsing administration of up to 3 mg has also proven effective. This is especially true for shift work and/or jetlag. The time of ingestion aligns itself according to that of the new time zone for jetlag, and that of the rest phase among shift workers.
If a classic substitution therapy is needed, as is the case for the elderly, then the pulsing dosage form is most appropriate rather than a slow or fast-releasing form. It should be ensured that the melatonin is provided to the body in sufficient amounts for about six to seven hours during the night. This is achieved through an amount of 3 mg, which can be increased without problems up to 6 mg if needed. Time of ingestion is about 30 minutes prior to going to bed, but always before midnight in order to avoid shifting the rhythm.
Supporting therapies such as in the case of a stroke or heart attack will certainly require a higher dosage. Initial studies successfully used amounts as high as 50 mg as an immediate measure in the form of fast-releasing melatonin. Administration follows immediately after knowledge of the event, so regardless of the time of day. Accompanying therapies among tumor patients also require a higher dosage. It is still currently disputed whether this form should be administered only in the evening, but this outcome is most likely. In the case of radiotherapy, a dosage of 15 mg appears to be sufficient, which is applied shortly before radiation.
Other applications such as for epilepsy, neuroprotection, and/or rhythm stabilizing profit best from a pulsing and/or delayed dosage form in an amount of 3-6 mg in the evening. It is important to note that children require a higher dosage than adults. Even though there are not a large number of studies present about the side effects of melatonin, all studies do show that melatonin is very compatible. A recently published meta-analysis of numerous studies that mostly administered over 10 mg showed that the frequency and severity of reported side effects was identical to those that occurred in patients that received the placebo. The presumably most likely unwanted side effect of melatonin will occur with an administration that is incorrectly timed. As melatonin will cause a shift in rhythm in this case, it can, if the shift is not desired, lead to health problems.