Melatonin seems to reduce high blood pressure

Melatonin taken at night over a prolonged period lowered blood pressure in people with hypertension, according to the results of a trial conducted in The Netherlands.

As Dr. Frank A. J. L. Scheer, currently at Harvard Medical School in Boston, and his associates note in the journal Hypertension, the internal clock appears to be disturbed in people with high blood pressure, and they theorized that melatonin could improve regulation of blood pressure.

The team enrolled 16 men with mild to moderate untreated hypertension, who were given 2.5 milligrams of melatonin or an inactive placebo 1 hour before bedtime. Compared with placebo, melatonin reduced blood pressure significantly after 3 weeks of treatment.

A single dose of melatonin did not significantly change blood pressure, and long-term treatment did not affect daytime readings or heart rate.