from Paul Bergner (bergner.concentric.net), Editor, Medical Herbalism (http://medherb.com):
I'm not surprised that melatonin is gone in Canada, and I predict that it will go the way of DHEA here in the U.S. -- meaning that it will be a prescription-only controlled item, treated like opiates.
I've just researched and written a lengthy article about melatonin, and frankly I am shocked that natural healers would use this substance casually like a sleeping pill. Melatonin is a powerful hormone that affects the entire metabolic cycle, not just the sleep- wake cycle. We rail against hormone-replacement therapy with estrogen- progresterone, and then casually offer patients enough melatonin to raise blood levels 10-20 times their normal levels. This is bound to be a Devil's bargain, and it is only a matter of time till regulatory agencies throughout the world discover this and rightfully take measures to protect the public.
For instance: melatonin production by the pineal gland appears to be an important part of the aging clock. The pineal glands of young mice, transplanted to old mice, make the old mice "younger" and they live about 1/3 longer. On the other hand, the pineal glands of older mice, transplanted into younger mice, immediately makes them "older" and they live about 1/3 shorter lives.
So what happens when some guy named Joe in Iowa takes ten mg of melatonin (about twenty times what you need to achieve normal blood level peaks) to sleep most nights for three years (this is actually happening all over the place today) and then can't get the melatonin? Will his pineal have lost its ability to produce the same levels as previously? Most hormones have a negative feedback loop of one sort or another -- would levels that high reduce endogenous production over time? Will poor Joe then age ten years over the next few months?
I think melatonin has a proper place in natural medicine, in the treatment or palliation of cancer, used for brief periods for jet lag, and possible for the elderly, and may be a few more uses. But IMO over-the-counter status is inviting health disaster.