Human Hormones – Melatonin, Steroids and More

You probably imagine that the largest, sharpest, and most dramatic hormonal change that human beings go through happens at puberty. All scientists assumed that once upon a time – until a few years ago, and most of us still do. However we now know that's wrong. The most quickest, and most thorough hormonal shift humans go through happens each and every night (and morning, in reverse) – but this change can't begin until the sun goes down AND we switch the lights, computer monitor, and LEDs off, entering true darkness. Moreover, if we don't enter darkness at very nearly the same time every night, our nightly hormonal changes may be substantially delayed, even though we are nominally in the dark. This is because the SCN, the very small part of the brain that's first responsible for initiating this hormonal tide, is designed by nature to cope with the very gradual change presented by the seasons – it's not designed to cope with the fact that your boss wants you to work until 3AM polishing his next presentation to the board, or your late-night video gaming sessions, or even the a somewhat later bed-time (onset of darkness) once a week. It may take many days to adapt to such shifts, by which time you've probably altered your hours yet again. Also, as I've mentioned, the SCN (brain) hasn't evolved, or been designed, to cope with interrupted nights – even a very brief flash of light (other than red) is simply interpreted as the beginning of a new day, and our entire hormone system instantly goes into reverse: which takes hours to largely reverse (by which time it's likely morning anyway.) This is part of the unfairness, and the fragility, of the light-detecting systems we have – even the briefest flash of bright white light at night upsets the whole system for long periods, yet turning off the lights and entering darkness triggers a healthy night-time hormonal cycle quite quickly only if we enter darkness at almost the same time every night. Evolution is the explanation for this. Nature is very regular about when the sun sets and when it doesn't, obviously (rare solar eclipses and lightning storms aside); and our bodies fully expect the same regularity from us today – they just aren't getting it, so we're getting ill.

The “SCN” I've been mentioning, or the Suprachiasmic Nucleus is a rather small clump of neurons in the hypothalmus. When it concludes from the information passed to it by the ipRGCs in our eyes that night has begun, it communicates this to the pineal gland where a release of melatonin begins. Melatonin has gotten a lot of attention during recent years, and very often for the wrong reasons and in the wrong ways. Not surprising, because most of that “information” about melatonin predates the recent discovery that melatonin is the body's master hormone. “Master” since melatonin controls and triggers, one way or another, nearly all the other hormones we produce, in turn controlling almost every process in the body. If melatonin isn't present in any quantity (as is true during the day or during extra exposure to artificial light), then steroids including aldosterone, are released instead as part of a day hormonal cycle. Conversely, if it's dark and melatonin is being produced, then steroids are largely withdrawn and replaced by a whole cascade of other hormones as the night hormone cycle begins.

But melatonin isn't just a master hormone, we now know that it's even more important: melatonin is the most powerful antioxidant we know of, by far – and this is no coincidence. It's the antioxidant that nature has provided us to clean ourselves with, in the darkness. It's so powerful that when a melatonin molecule combines with a dangerous free radical molecule that would otherwise cause random changes in our bodies, it is transformed into another molecule which is also an antioxidant and can serve to clean up one more free radical, to boot! We need melatonin for it's antioxidant properties just as much as we need to have it present to control our nightly hormonal cyle. But of course, it only comes out at night: but this means during true, uninterrupted, consistent darkness. Open your child's bedroom door to check on them with the hall light on, vary your (or their) bedtime, or let them sleep into morning light, and you are depriving them of not just melatonin itself, as an antioxidant, but much of the beneficial and necessary processes our bodies are meant to perform during darkness.