Posted by Larry Hoover on July 22, 2004, at 6:36:47
In reply to question about Melatonin, posted by 1980Monroe on July 21, 2004, at 22:15:28
> Why is it warned not to take more than 3mg in less than 24hours.
>
> Is Melatonin a hypnotic by the way, or just make you more in the mood for sleep.Melatonin is a hormone, released by the pineal gland, which substantially increases your brain's ability to let go of consciousness, and permit sleep. Its release is highly correlated to the light/dark cycle (kind of like a metronome for the brain), but some psychiatric disturbances reduce the level of melatonin, resulting in insomnia and other sleep disturbances. Moreover, as melatonin is synthesized from serotonin, defects in the latter pathway will affect both of them.
I have no idea why melatonin is commonly found in 3 mg doses. That is about 10 times the normal physiological release of melatonin from the pineal gland. Maybe they once thought that melatonin is poorly absorbed (it's not), or that only a fraction of it made it all the way to the brain (melatonin is one of the most potent antioxidants ever discovered), or maybe they just do it that way because that's the way they've always done it. The problem is, too much melatonin has the same effect as too little. It does nothing.
We're accustomed to thinking that the effect of a drug is dose-dependent. The more you take, the more effect it has. Like alcohol. But not all drugs work that way, and primarily when they have hormonal targets. If the drug or hormone is too strong (from a signalling perspective), the receptor simply turns off. It's like tilting a pinball machine.
The effective dose of melatonin might be as little as 0.2 miligrams, but it might be up to 6 miligrams. There is a lot of individual variation (and may reflect a receptor-mediated defect). I use Natrol melatonin, (cheap at Walmart). I break the 3 mg tablet down to roughly 8 parts. That dose works for me. If I take a whole tablet, nothing happens. Actually, I sleep worse, because my own natural melatonin has been over-whelmed by the drug form, and the system has shut down.
Lar
poster:Larry Hoover
thread:368799
URL: http://www.dr-bob.org/babble/alter/20040718/msgs/368866.html