Melatonin May Lower Blood Pressure

A recent study has found that taking supplements of the hormone melatonin at night helped reduce morning blood pressure levels in men.
( [email protected] ) Apr 21, 2004 01:09 PM EDT

Increased peak in morning coronary incidents

The study, published in the journal Hypertension, examined the hypothesis that disturbances of the body’s circadian rhythm might be one of the underlying mechanisms of an increased peak in morning coronary incidents, and that restoring the body’s biological clock using melatonin might counteract that.

Melatonin is a hormone produced by the brain’s pineal gland when darkness arrives. As production of the neurochemical rises, the brain becomes less alert and sleepy. Melatonin levels decline with exposure to light, and remain low throughout the day.

Lower systolic and diastolic blood pressure with melatonin

Scientists studied a group of 16 men, all of whom had untreated high blood pressure. The subjects were randomly assigned to receive a placebo, a single dose of melatonin taken at the beginning of the study, or a 2.5 mg dose of melatonin one hour before bedtime for the duration of the research.

While the men taking the placebo or the single dose of melatonin experienced no change in their blood pressure, those taking the hormone each night throughout the three weeks had lower systolic and diastolic blood pressure. Participants taking melatonin also reported sleeping better, but this was not necessarily related to changes in their blood pressure.

See your healthcare practitioner before taking melatonin.


1. F. A.J.L. Scheer; Buijs, R.M., Mairuhu, G., Van Montfrans, G. A., Van Someren, E. J.W., “Daily Nighttime Melatonin Reduces Blood Pressure in Male Patients with Essential Hypertension,” Hypertension, 2004 43: 192-197.