Melatonin is a hormone. It tells your body that it’s nighttime and it’s time to go to bed. It is not an herb, a vitamin, or a mineral. Hormones are naturally produced by your body as you need them. Which means it is very unlikely that someone has a melatonin deficiency. While a melatonin supplement could be considered natural, in most cases, it doesn’t come from the earth. There are exceptions of foods that contain melatonin, but this is a different type of melatonin than what is produced in your brain. Your melatonin levels can be tested with a blood test, urine test or saliva test. If you are concerned that you may actually be melatonin deficient, ask your doctor about testing.
Melatonin is produced by the pineal gland and sends a signal to regulate the sleep-wake cycle in the sleep center of the brain. Interestingly, melatonin is also produced in the retina, the skin, and the GI tract, but this is not the melatonin what affects your biological sleep clock.
This is the really important thing you should understand about melatonin: Melatonin is a sleep and body clock regulator – NOT a sleep initiator. Melatonin works with your biological clock by telling your brain when it is time to sleep. Melatonin does not increase your sleep drive or need for sleep.
Melatonin is called the “Vampire Hormone” because it is produced primarily in darkness and inhibited by light. The levels of your melatonin increase in the middle of the night and gradually fall as the night turns to morning, so exposure to light before bed can push your biological clock in the wrong direction – making melatonin ineffective.
Melatonin treats Circadian Rhythm Disorders (where you sleep the right amount of minutes but your body clock is at the wrong time), Shift Work Sleep Disorders, and early morning awakenings – all things that deal with the timing of your need to sleep. Melatonin is not considered an effective treatment for insomnia.
Melatonin in pill form does not function like your body’s naturally produced melatonin: It affects the brain in bursts and rapidly leaves the system, instead of the slow build-up and slow wash-out that your body’s naturally produced melatonin experiences.
The correct dosage of melatonin can be a problem. According to research conducted at MIT, the correct dosage of melatonin for it to be effective is 0.3 - 1.0 mg. Many commercially available forms of melatonin are in 3 to 10 times the amount your body would need. In fact, there is some evidence that higher doses may be less effective. In Europe, melatonin at very high doses has been used as a contraceptive.
Melatonin can have side effects. Doses of melatonin (2-3 mg or higher) have reported side effects of: