Melatonin is appropriate for supplementation when low melatonin levels are suspected, or when specific conditions are being treated with higher doses. Dosages of 1-3mg one hour before bedtime are more than sufficient to achieve its sleep-inducing quality. Doses as low as 0.1mg have produced a sedative effect when melatonin levels are low. Doses in the range of 10-50mg are used in cancer treatment and possibly other conditions. While melatonin is widely touted as an antioxidant, the current evidence suggests that it is not an important antioxidant when typical concentrations are used.

Melatonin has shown itself to be virtually free of any significant adverse effects. A lethal dose of melatonin cannot be identified which is a rare event in toxicology studies. However, more mild side-effects, such as headache, morning sleepiness, fatigue or nightmares, are experienced by average individuals when they try melatonin. Perhaps it is because these people do not require supplementation. In spite of the non-existence of serious side-effects, it is a cautious and generally made recommendation that melatonin should only be taken when your own production is low unless a serious condition is being treated with higher doses.

Generally speaking, melatonin should not be taken during the day as it may disrupt circadian rhythms and cause drowsiness. There is no evidence that one method of delivery is substantially better than another (tablet, capsule, sublingual), but the sustained-release form might best duplicate the body's normal pattern of release, and help those who fall asleep easily but awaken too soon.

Safety Issues
Melatonin is probably safe for occasional use (as in plane travel), but some real concerns exist about using it on a regular basis. It should be noted that melatonin is not really a food supplement. It is a hormone, just like estrogen, thyroid, or cortisone, but without the obvious side-effects seen on overdosing. It is not a part of your daily diet, unless you are in the habit of eating pineal glands! Because the body's own production of melatonin is probably the equivalent of only 0.1mg daily, when you take melatonin for sleep, you may tremendously exceed the body's own production. The consequences of doing so on a regular basis are completely unknown.

If melatonin excites instead of calms, this may indicate a hormone imbalance in women. Inositol at low doses (650mg, which is contained in 3 tbsp of lecithin) at bedtime may help. When depression is also present, 5-HTP, St. John’s Wort or tryptophan may help as well.

Elderly patients using 2mg of controlled-release melatonin are much more successful at weaning themselves off of medications such as alprazolam, oxazepam, brotizolam, and lorzepam. In one study, 14 out of 18 patients were able to completely discontinue their benzodiazepine treatment after 4 to 6 weeks of melatonin therapy.

In the elderly, 0.3mg melatonin before bed was an effective dose for enhancing sleep. Larger doses (3mg) had the same effect but also caused hypothermia and levels remained high during the day, not dropping as is normally the case. [J clin Endocrinol Metab 2001;86: pp.4727-4730]

Cautions, Contraindications and Side-Effects
On the basis of theoretical ideas about how melatonin works, some authorities specifically recommend against using it for depression, schizophrenia, autoimmune diseases and other serious illnesses, or by pregnant or nursing women. Do not drive or operate machinery for several hours after taking melatonin.

If you take too much melatonin, you may experience the following effects:

• Drowsiness upon arising
• Wild, not just vivid, dreams
• An excess of the thyroid hormone (T3), resulting in waking up nervous, sweating, and with palpitations
• Decreased estrogen and progesterone levels. If melatonin excites instead of calms, this may indicate a hormone imbalance in women. Inositol at low doses (650mg, which is contained in 3 tbsp of lecithin) at bedtime may help.

One Dutch study suggested that 30mg of melatonin daily could even act as a contraceptive.