PhotoperiodEffect.com

20. - Forget more darkness, I'm busy. I'll just take melatonin – or even better pills when they come along. Let's fight technology with technology.

Probably a bad idea. I've mentioned a few reasons why in the reply to objection 12., and I'll repeat some of that along with much more detail here.

First, we know that the body tries to adjust it's own production of melatonin if you are taking it in pill form as well as producing it at night, naturally. It's a pretty good guess that this might reduce your own production as your body tries to achieve homeostasis. Whether or not this is so, it is known that taking melatonin will affect the timing of your own melatonin production amongst other important things. [16397720] Taking extra (i.e. “exogenous”) melatonin shouldn't be done lightly. Too much melatonin can easily slop over into the daytime, upsetting natural sleep and hormone rhythms [12069043].

Second: given that taking melatonin upsets your own production of melatonin; whatever you do, DO NOT TAKE MELATONIN INCONSISTENTLY OR SLOPPILY. Just as taking mega doses of Vitamin C and then dropping it is a bad idea, so is taking melatonin some of the time likely a bad idea. If you have a life-threatening illness, say cancer or an illness involving ischemia/reperfussion, or shingles which might otherwise result in severe life-long pain from neuralgia, okay – take it while you're in danger and accept that there will be some adverse consequences, possibly permanent (we just don't know) after you stop. If you are elderly, sure you can no longer produce adequate melatonin, and are willing to be perfectly consistent taking melatonin every night for the rest of your life, that might be excusable as well, but at least some research suggests that melatonin doesn't decrease with age [7562374] [11231989].

Third. Most importantly, just taking melatonin doesn't do the whole job that darkness does. Pardon the technical language, but: “the time-of-day message penetrates into all tissues, interestingly not only by means of hormones but also by a direct neuronal influence of the SCN [suprachiasmatic nucleus] on the organs of the body. .... At the same time, the SCN-autonomic PVN [paraventricular nucleus of the hypothalamus] axis fine-tunes the organs by means of the autonomic nervous system for the reception of these hormones.” [12697033] In other words, without the body's clock signaling the beginning of darkness, melatonin will not function in the same way it normally does, in the presence of darkness. This by itself is reason enough to believe that simply taking more melatonin cannot possibly compensate fully for an absence of genuine darkness in our lives.

We also have distributed clocks around our body, including our intestine and skin, so not just the central clock that triggers changes in melatonin. Light will affect these clocks badly even if you are taking melatonin. Worse, research seems to show that even your central clock, governed by the SCN pathway through the pineal gland can't be fooled just by taking melatonin pills. At least some experiments with animal pinealectomies suggest that merely replacing the melatonin the pineal gland produces at night doesn't eliminate the most spectacular consequences of removing the pineal gland, namely scoliosis (curved spines.) This is an rather large clue that melatonin isn't the only health-giving gift sufficient real darkness gives to us and that trying to get by with melatonin pills is highly likely to be a doomed strategy. Also, it now seems that the daily rise in blood sugar controlled by the SCN isn't mediated by melatonin. [15342726] As well, there seems to be a tachykinin “pathway” that's distinct from the melatonin pathway, the function of which isn't yet known. [15926922] No doubt other important daily changes are not in the melatonin pathway, either – this note is not meant to be exhaustive. We are nowhere near the state of knowledge of human chronobiology that might justify such tricks as juggling critical human hormones as an alternative to just shutting off the lights at night. Imitating nature as closely as possible by switching the lights off more consistently for longer periods is without question our best available strategy to improve our general health, lifestyle and well-being: rather than more drugs. No doubt it will be for a long time to come.

Some further evidence that melatonin supplementation is not a complete substitute for darkness comes from a meta-review concluding that “There is no evidence that melatonin is effective in treating secondary sleep disorders or sleep disorders accompanying sleep restriction, such as jet lag and shiftwork disorder.” [16473858] It would be pleasant to think one more pill would let us keep the party going and stay up long after the sun is down with no physical or emotional consequences, but there's a lot of evidence that there is no such pill, or drug, available to us. Just nature's darkness.

Fourth. Careful of the dose! A 2001 study showed the most effective dose of melatonin is .3 mg [11600532] – but the usual dose you can buy in a health food store is 3 mg, ten times that amount. The same study showed that this amount slopped over into the day, rather than being available only at night when it should be. Not only this, but there's evidence from primate studies that too much melatonin degrades sleep: “While low melatonin doses (5-20 microg/kg) did not significantly affect nighttime sleep efficiency, higher pharmacological doses reduced sleep efficiency and increased sleep fragmentation at night, and reduced spontaneous daytime locomotor activity.” [12062316] The dosage available in health food stores may change to something more reasonable one day, but remember: people vary in all things, so you shouldn't expect that the largest dose for you that won't slop over into the daytime will be the same as for the average person.

Fifth, if all that isn't enough, melatonin in small doses (in rats) helps sexual performance, but repeated large doses suppress sexual performance. [10996140]

Sixth, if nothing else, in the presence of light steroids will likely interfere with the cascade of all sorts of other hormonal reactions, immune cycles, etc, that melatonin is supposed to trigger. So for this reason too, it may all come back to light.