The pineal gland is the size of a pea and sits right in the middle of the brain. The pineal gland is regulated by both light and through the actions of the suprachiasmic nuclei (a nearby section of the brain that provides a wave of wakefulness at around 8am and 4pm). When nightime comes, it produces melatonin, a hormone that keeps your body clock in touch with the world around you.
Melatonin is also available in supplementary form. Long-haul travellers have long made use of the hormone to tune their body clocks to their new timezones. However, in recent years, individuals have begun waking up to melatonin’s potential as a sleep aid. However, disagreements rage as to its effectiveness, with some lauding it as a lifesaver and others pointing to the hormone as a potent sleep-disruptor.
As usual, such arguments are borne of ignorance and haphazard use of the supplement. Individuals with disrupted body clocks, high evening cortisol levels or intrinsically low melatonin will find that a satisfying nights sleep remains elusive until they add melatonin supplements. At which point, something magical happens; a truly blissful night’s sleep. These people will, unsurprisingly, tell you that ‘melatonin is a lifesaver’.
Yet there there are plenty who have the same problems falling asleep or staying asleep, but find that melatonin has the opposite effect; they find themselves coming to in the early hours, fully awake and unable to go back to sleep no matter how much they try. These are the individuals you may see telling you that ‘melatonin is useless’.
So why can it work so well in one group and yet have the opposite effect in others? Let’s investigate.
Typically taken in dosages of 1-9mg, melatonin has two primary effects:
1. increase nitrous oxide (and therefore blood flow) to parts of the brain involved in sleepiness
2. blunts the responsiveness of the adrenal cortex to ACTH (thereby lowering cortisol)
In an individual with a disturbed body clock, both effects are equally important. A traveller may have arrived in Tokyo from London, a timezone difference of 7 hours, and finds himself staring at the ceiling at midnight (local time). This is because his cortisol levels still at a moderate level, telling the body that it’s still late afternoon, and the clock-dependant alerting of the suprachiasmic gland is fortifying the body’s second alerting phase of the day. There’s no melatonin being released. He then takes melatonin, and the situation changes. The brain becomes drowsier. Cortisol levels decrease. He sleeps and is likely to get a good night’s sleep (still not likely to be perfect on the first night, but good enough). Three more night’s of melatonin use and he has won the timezone battle.
In an individual with high cortisol levels, it is the second effect that is key. The drowsiness caused by the first effect is welcome, but they were likely tired enough for this to be irrelevant. The main problem is this case is that, when cortisol is high at night, the individual will feel relaxed, sleepy but simply will not cross the borderline into sleep. A frustrating situation, indeed. Melatonin has a potent effect at lowering the cortisol levels in the bloodstream, removing the final (but powerful) obstacle standing in the way of this insomniac and a great night’s kip.
However, there are also those individuals who experience low cortisol levels. In such cases, we can expect the adrenaline levels to be raised (a typical compensation the body is forced to make in order to sustain reasonable blood sugar levels, and an inevitable consequence of the overactivity of the HPA axis when cortisol levels are too low). A reliable pattern is that the lower the cortisol, the higher adrenaline. Anything that pushes cortisol down further (eg melatonin) will trigger an even higher level of adrenaline, the last thing you want if sleep is a priority. Given the pharmacodynamics of melatonin taken oral forms, low-cortisol individuals are most likely to wake up ‘wired’ around 3-4 hours after taking the supplement (when their cortisol is at its lowest). This does not make melatonin ‘bad or ‘useless’, simply highly inappropriate for this group.
At this point, it is important to mention that melatonin does not need to be used long-term. Most individuals will find that 3-6 weeks of usage will do the job admirably. After this time, the bodyclock (and the cortisol levels that accompany it) should be tuned to the point that melatonin is no longer required.This means that an individual with high night-time cortisol will see a spectacular improvement in sleep upon the introduction of melatonin, but will likely notice no difference when they remove it a few weeks later. Sleep remains excellent.
On a similar note, for those who like the ‘insurance’ that melatonin appears to provide, I suggest you stop using it in the recommended time zone. This is not because it has an toxic effects (it is remarkably non-toxic), but because it can end up ruining your sleep! How so? Well, if your cortisol levels are high at night-time, this means that your body is stressed. And poor sleep is a huge candidate in this. When your sleep improves, your stress levels reduce. As a result, your cortisol drops and, with it, your night-time cortisol. And guess what happens when you over-suppress low cortisol levels?
I hope this unravels the mystery of melatonin, and also outlines how incredibly useful it can be to bring about refreshing sleep, the cornerstone of our well-being.
Modern medicine tends to fall into the trap of considering an item ‘effective’ or ‘ineffective’, ‘safe’ or ‘unsafe’. But to provide a black-and-white label on any one herb, hormone or drug is to be totally ignorant of the differences in our internal biochemistry. We are all different. Luckily, measuring your cortisol levels with an adrenal stress index test or talking to a specialist removes chance from the equation is the first step towards guaranteeing a superb night’s sleep. Every night.