In addition to its use as a sleep aid, melatonin exerts possible effects on cardiovascular parameters, including anti-oxidative action on LDL, reduction in sympathetic (adrenaline-driven) tone, and reduction in blood pressure.
Several studies document the blood pressure-reducing effect of melatonin:
Effects on BP tend to be modest, on the order of 5-8 mmHg reduction in systolic, half that in diastolic.
But don't pooh-pooh such small reductions, however, as small reductions exert mani-fold larger reductions in cardiovascular events like heart attack and stroke. NIH-sponsored NHANES data (see JNC VII), for example, document a doubling of risk for each increment of BP of 20/10. The Camelot Study demonstrated a reduction in cardiovascular events from 23% in placebo subjects to 16.7% in subjects taking amlodipine (Norvasc) with a 5 mm reduction in systolic pressure, 2 mmHg drop in diastolic pressure. Small changes, big benefits.
Many people take melatonin at bedtime and are disappointed with the effects. However, a much better way is to take melatonin several hours before bedtime, e.g., take at 7 pm to fall asleep at 10 pm. Don't think of melatonin as a sleeping pill; think of it as a sleep hormone, something that simply prepares your body for sleep by slowing heart rate, reducing body temperature, and reducing blood pressure. (You may need to modify the interval between taking melatonin and sleep, since individual responsiveness varies quite a bit.)
I also favor the sustained-release preparations, e.g., 5 mg sustained-release. Immediate-release, while it exerts a more rapid onset of sleep, allows you to wake up prematurely, The sustained-release preparations last longer and allow longer sleep.
The dose varies with age, with 1 mg effective in people younger than 40 years, higher doses of 3, 5, even 10 or 12 mg in older people. Sustained-release preparations also should be taken in slightly higher doses.
The only side-effect I've seen with melatonin is vivid, colorful dreams. Perhaps that's a plus!
Controversy over the Safety of Melatonin in Autoimmune Diseases
In general, although melatonin is one of the least toxic substances known, it is not recommended for people with autoimmune diseases or immune system cancers because of its ability to stimulate immune function. However, in numerous studies of people with specific autoimmune disorders, melatonin can modulate the immune system in a beneficial way.
Studies show that melatonin can inhibit cytokine production and reduce inflammation. [JM Guerrero and RJ Reiter, Melatonin-immune system relationships, Current Topics in Medical Chemistry, Feb 2002; 2(2): 167-179].
Current research suggests that melatonin should not be used in autoimmune diseases unless it is used as a therapy in a closely supervised clinical trial or under the guidance of a qualified practitioner. This recommendation may change as further studies of melatonin’s effects on the immune system are complete.
Thanks Harry. There are so many positive benefits from using melatonin...seems like every time I look up a natural remedy for a condition I have, melatonin is recommended. Life Extension said pretty much the same thing as this article...darned if you do, and darned if you don't! They probably had one bad apple out of a bunch of research so now doctors are afraid to recommend it. I think I'll try 1 mg and work my way up to 5 mg to try it. I used the name "nightowl" on here for a reason. I have always stayed up till 3 or 4 AM and slept all day, but recently I sometimes stay up 20 to 30 hours at a time, without really feeling overly tired. I also have sleep apnea so probably don't sleep that sound when I am asleep. I use a BIPAP machine and oxygen when I sleep. It was mentioned that melatonin caused vivid dreams...I almost never dream, and if I do I don't remember it.