Serotonin and Melatonin and Their Involvement in Sleep

Serotonin and Melatonin and Their Involvement in Sleep

Whether you have difficulties with sleep, or you just want to promote as much restful, restorative sleep as possible, you probably have done a little research into the biochemistry of sleep. Along the way, you may have heard about serotonin and melatonin and how important they are for sleep.

But you might not be clear on the roles of each, nor be sure entirely sure what they are. In this post, we will introduce you to both, and explain exactly how they are involved in your daily sleep-awake cycles.

What is Serotonin?

Serotonin is classified as both a hormone and a monoamine neurotransmitter. It is also called 5-hydroxytryptamine (5-HT).

Serotonin is involved in regulating quite a few different things in your body, including:

  • Sleep
  • Pain
  • Learning and memory
  • Digestion
  • Nausea
  • Wound healing
  • Mood
  • Libido
  • Bone health
  • Hunger
  • Body temperature

You might assume that serotonin is produced in your brain, and it is—but only about 10% of it! The rest is in your intestinal tract.

When levels of serotonin are too high or too low, patients may experience problems with sleep, pain, mood and digestion.

Key point: Serotonin is a hormone and neurotransmitter that regulates sleep and other bodily functions.

What is Melatonin?

Melatonin is another important hormone. Your brain produces it in higher amounts at night and lower amounts during the day. This makes it a vital component of your sleep-awake cycles, regulating your circadian rhythms.

Key Point: Melatonin is a hormone that regulates sleep cycles.

What are the Roles of Serotonin and Melatonin in Sleep?

Now that you are familiar with serotonin and melatonin, let’s delve a little deeper into how they are involved in promoting healthy sleep.

McGill University explains, “Sleep is triggered by two inter-related processes: the production and build-up of hypnogenic [sleep-producing] substances in the body while we are awake, and cyclical fluctuations in substances such as melatonin that are associated with our body’s biological clock.”

One of the sleep-producing substances to which McGill is referring is serotonin. The University points out that sleep disorders and mood imbalances often go hand in hand in part because of serotonin’s role in regulating both.

McGill also talks about the relationship between serotonin and melatonin. The university writes, “Serotonin also plays an important role in sleep because the body uses it to synthesize melatonin. Melatonin is produced at night and plays a fundamental role in regulating the body’s biological clock. In fact, melatonin governs the entire sleep/wake cycle, whereas serotonin is involved more specifically in wakefulness, in triggering sleep, and in REM sleep.”

That means that if your serotonin levels are not ideal, that could also end up throwing off your melatonin levels. This would essentially end up doubling your problem.

Key Point: Serotonin and melatonin work in concert to regulate your sleep cycles.

How Do You Know if Your Serotonin or Melatonin Levels are Off?

There are tests for melatonin and serotonin levels. But it is important to know that you can only test the levels of serotonin in your blood, not the levels of serotonin in your brain.

So, often, doctors will try and determine based on your symptoms what might be going on in your body with your hormone levels.

It is also worth pointing out that hormone levels fluctuate considerably based on a range of factors.

That means that a single test does not give you an accurate portrait of your hormone balance. So, there is likely to be some trial and error while you are trying to pinpoint what is going on.

Key Point: While there are hormone level tests, it can be a challenge to know if your levels are high, low or normal.

What Can You Do to Increase Serotonin?

If you want to try to boost your serotonin levels to support healthy sleep and mood, one option is to try taking 5-HTP, which is a serotonin precursor.


You may find this extra effective if you are doing it in conjunction with taking healthy amino acids such as L-tyrosine and L-theanine. You can also take passion flower extract to support restful sleep and enhance mood.

Regular exercise, a nutritious diet, and proper management of stress may also all help you to regulate your serotonin levels.

Some food you can consider eating more of to increase your serotonin levels include turkey, eggs, pineapples, cheese, salmon, tofu and nuts.

Key Point: There are many natural ways to promote higher serotonin levels.

What Can You Do to Increase Melatonin?

Just as there are certain foods that can help you to increase serotonin, there are also some foods that may help you to enhance your melatonin levels.

High-melatonin foods to incorporate into your diet include eggs, tart cherries, goji berries, fish, milk and nuts.

While you are at it, you can take steps to try and keep your circadian rhythms smooth and regular. During the day, try getting out in the sun a bit. At night, avoid over-exposing yourself to blue light. That means that you should consider either switching off your devices a couple hours before bedtime, or using blue light filters.

Key Point: Diet and light exposure impact melatonin levels.

Balance Your Hormones for Restful Sleep

Let’s review what we just learned. Melatonin and serotonin are both hormones that are involved in regulating your sleep cycles. For your sleep cycles to be regular, both of these hormones need to be in balance.

If your serotonin or melatonin levels are low, you can try adjusting your diet, exercising more, managing stress, taking natural supplements, and controlling your exposure to blue light. All of these steps should help you to bring things back in balance. You can also talk to your healthcare provider about whether there are additional treatments that might help you support a healthy sleep cycle.


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