A study in the February, 2004 issue of Hypertension suggests that a daily bedtime dose of melatonin can reduce the nighttime blood pressure and improve sleep quality.
Melatonin is a naturally-occurring hormone and neurotransmitter that influences the suprachiasmic nucleus (SCN) in the brain. The SCN is thought to regulate several of the body's daily biological rhythms, including heart rate and autonomic tone. Recent studies have suggested that SCN function may be suppressed in some patients with hypertension, and it has been speculated that abnormal SCN function might cause at least some of the blood pressure elevation seen in these patients. The investigators who conducted this new study postulated that giving melatonin might restore normal SCN function, and thus perhaps improve blood pressure.
Sixteen 16 men with hypertension were thus enrolled in a randomized trial, with one group receiving nighttime melatonin (2.5 mg one hour before sleep,) and the other group placebo. After 3 weeks, patients receiving melatonin had significantly reduced systolic and diastolic blood pressures at night, as well as better sleep quality. The investigators noted that improvements in blood pressure and sleep were not seen after one dose, but only after several days of treatment.
In the recent past melatonin - available over the counter in the US - was widely advertised as a means of improving sleep. For reasons unclear to DrRich, those who advertise such "natural remedies" have appeared to move on to other things. In any case, the stuff is unregulated and the purity of available preparations is unknown. No formal trials have been conducted of melatonin's long-term effects.
The authors of this new study caution that melatonin should not be used for treating hypertension based on this single trial, and that more studies are required. It is not clear when such studies might be conducted, inasmuch as Melatonin, being invented by God and not by a drug company, cannot be patented, and so the pharmaceutical industry will be reluctant to pursue the expensive, time-consuming trials necessary to take this substance through the required regulatory pathways.
