Not so long ago, updates on how we cycle from wake to sleep and back were discussed in some detail in Real Answers.

Since that time, the use of melatonin to help people fall asleep has continued to rise, with some estimates putting the number of Americans using it up to 3 million of us.

What is Melatonin?

Melatonin is a hormone.  It actually is made from the single amino acid tryptamine, which is closely related to the famous amino acid tryptophan found in turkeys and which makes people groggy on Thanksgiving.

Now a hormone is a chemical used for one group of cells in the body to communicate an initiative for another group of cells to take.

Such communications are very familiar to anyone who has raised their hand.  Go ahead, raise your right hand.  To do that a communication must be delivered from your left brain down to your right arm, and that communication is a bolt of electricity designed for one purpose, to get the muscles of your right arm to move your arm so your right hand goes up.

Hormones are like nerves in that they communicate actions, but they do so by issuing a chemical signal, not an electrical one.

Perhaps the most familiar hormone is adrenaline, made appropriately enough, by the adrenal glands.   The adrenal glands pump out adrenalin when the body desires to have all the events adrenalin makes happen, happen.  Those all center around heightened awareness and alertness as we know.

Other hormones communicate other actions- insulin manages glucose and fat, testosterone signals masculine actions, estrogen feminine ones.

And then there is melatonin.  Melatonin is a hormone and it definitely delivers a very specific communication.  It starts in a part of the brain called the pineal gland, and it travels from this origin to two main parts of the human brain- the suprachiasmiatic nucleus of the hypothalamus and the stalk of the pituitary gland.  Another destination is located on our retinas.

What Does Melatonin Do?

Perhaps the most interesting function this hormone does is a cyclical pattern of stimulating the brain to shift from wake to sleep.

If you think about it, sleep and wake are two very distinct ways to be.  It is hard really to do both fully.   It’s not like our multi-tasking world where our mind, when awake, can listen to music, read a book, sort of listen in on a conversation, and way in the background have a TV show going.  But if you are wide awake, it is hard to also be sound asleep.  And if you are deep into sleep, you cannot be wide awake.

So here are these two very distinct states.  And for almost every 24 hour period of our lives, we move from one to the other and back again.

The mechanism by which life alternates from wake to sleep and back varies by animal, but in animals like us, there is an intricate rise and fall of a series of chemicals in the brain, centered around a tiny cluster of cells that sit above our pituitary glands, in the region of our hypothalamus.  This spot is physically just on top of where the paths of our optic nerves cross from one side of our head to the other.  This cross-over is called the optic nerve chiasm, and the area just above it is the supra-chiasmatic area, or suprachiasmatic nucleus, or SCN.  The tiny clump of nerves cells in the SCN performs a rather remarkable daily dance, in which certain compounds accumulate, until a signal is given for them to drop.  It is light, even more than melatonin, that directs this dance.  As the sun sets and the world darkens, a gland watching how much light is around us, the pineal gland, makes our hormone melatonin.

Once melatonin is released from the pineal gland, it communicates to those cells in the SCN, and they begin to drop their maintenance of certain chemicals, which triggers the entire brain to switch modes, from awake to asleep.  Once that switch is thrown, you fall asleep.

As you sleep the chemicals shut down in the SCN slowly start to accumulate, and when they hit a high enough level, and when light reappears, the switch to be asleep is turned off, and, you wake up.  Slowly the waking chemicals in the SCN drop over the day, until the light drops and melatonin spikes, and you click back into sleep.

And on it goes.

You can now see, melatonin is a hormone, and it communicates from its base in the pineal gland to the centers that control sleep, to go to sleep.

This also means melatonin is NOT a sedative.  It is a switch operator, helping the switch to turn on sleep to turn on.  Sedatives make you groggy, they cause the brain overall to slow down.  Alcohol is a sedative, it does not click the sleep switch.  Hopefully you can see a sleep switch activator and a sedative really are not the same at all.  In fact, many sedatives that make you groggy mess up the regular daily sequence of switching from wake to sleep.

One last point of how melatonin works.  The pineal gland watches at all times for levels of light around us, and when those levels drop, it issues its melatonin.  So one way to keep melatonin from being released is to stay surrounded by lots of light.  And, it turns out there is one type of light that really tells the pineal gland to not bother making any melatonin- it’s blue light.  Most computer screens glow with bright white light that is loaded with blue lights, so do TVs, and room lights.  Some people use blue light filters- special bulbs, special screens, or even yellow glasses, to keep the constant flood of blue light from blasting our pineal glands when we are nearing bedtime, and that helps naturally boost melatonin production and the ease of falling asleep.

Using Melatonin

So what happens when you or your child takes some melatonin?

Based on many people’s experiences, it seems to help you fall asleep, swallowing some melatonin appears to help that switch in the SCN switch our minds from awake to asleep.

Seems.

The truth is that we really do not know.  No one actually measures the SCN activity after one takes a melatonin pill or chews a melatonin gummy.  Maybe part of the impact is that the person giving the melatonin and the person taking it expect to fall asleep, moving the SCN to throw the switch.

We just do not know.

But one thing we do know is that millions of people have taken melatonin, some every night for many years, and not many are reporting side effects.  Whenever you ask millions of people if they ever experience headaches, stomachaches, you will always find many that do, with or without taking taking any medicine, so when so many millions take melatonin, there will be many who report experiencing headaches, stomachaches and other symptoms.  But we don’t see any clear patterns of melatonin causing a characteristic list of side effects.

This is all a long way towards saying two things:

1. It appears that taking melatonin at bedtime, at any age, helps the switch that flips one’s mind from awake to asleep to activate.
2. We are not exactly sure how it accomplishes this, if it is like how it works naturally, or some other mechanism.
3. The use is so widespread, so many millions have used it, and so far not many significant side effects are noted.

The Complexity of the Switch from Wake to Sleep to Wake

Most discussions of use of melatonin place hope in the concept that melatonin is a switch. That if you take melatonin or give it to your child, it will switch your state from awake to asleep.  And many people have just this experience.

But this concept belies the complexity of this transition.   The brain requires sleep to function, all life forms with a brain sleep.  So the switch to go from wake to sleep for all of us is absolutely essential.  But there is another imperative.  We must be able to stay awake, or go from falling/being asleep, at any moment.  Being asleep is an extreme state of vulnerability and danger is always lurking.  Imagine any animal unable to protect itself while sleeping, there wouldn’t be many of such species.  So all of us have the ability to suddenly stop the transition to sleep or initiate the switch to wake.

This means “falling” asleep is always open to interruption, or even regular difficulty.  Why else even have the need for melatonin?

The main reasons we struggle to fall asleep include, but are not limited, to the following:

• Not wanting to fall asleep
• A mind full of active thoughts
• Worries
• Anxiety, depression, mania
• Illness
• Worrisome signals- sounds, lights, events
• A wide variety of medications
• Caffeine
• Other dietary influences per person
• Light
• Activities

The point is that if you or your child is looking like using melatonin might be helpful, it makes sense to start with thinking about what is keeping you or them awake at bedtime?

Bottom Lines

1. Lots of kids and adults struggle at bedtime with that amazing switch that swings our minds from being awake to asleep.
2. Melatonin is hugely popular medication now being used to seemingly throw the switch from awake to asleep.
3. It works amazingly well for millions of people, and without much incidence of serious side effects.
4. Melatonin is a hormone, or a signal used by cells in our pineal gland which monitor light hitting our body, to communicate with cells in our hypothalamus that determine, is one awake or is one asleep?  Melatonin is derived from tryptophan, the amino acid in turkey that makes so many sleepy.  And in its chemical structure still looks very much like an amino acid.
5. The mechanism in the area of the hypothalamus that sets our mind in the wake or sleep mode is right above where parts of our optic nerves from each eye cross from R to L and L to R, a spot called the optic chiasm.  Since it is right above there, it is called the suprachiasmatic nucleus, or SCN.  The handful of cells in the SCN that move us from wake to sleep and back and forth weave a complex rising and falling sequence of chemicals.  Melatonin pushes that up and down sequence to initiate sleep.
6. The switch in the SCN that makes us “fall” asleep is designed to halt or reverse, so many, many influences can stop us from falling asleep when we want to.  Paying attention to all those realities in our life is the best first step to creating a routine of falling asleep easily.

To better rest,
Dr.  Arthur Lavin