Close to 50% of Americans report fatigue three to seven days a week during the day. 35% of adults report getting less than seven hours of sleep per night, the minimum recommended amount. Quality sleep has been linked to positive health outcomes and is dependent on several factors, including stress, temperature, and the production of the hormone melatonin. Melatonin is our body's primary sleep hormone, affecting the quality and quantity of sleep.

This article will discuss melatonin, including its role in the body, how to test for it, and ways to increase it in your body.

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What is Melatonin?

Melatonin is a hormone made in the pineal gland in the brain from neurotransmitters and plays a central role in the circadian rhythm, or the body's sleep-wake cycle. When light hits our eyes in the morning, the light waves get transferred to an area in our brain called the suprachiasmatic nucleus (SCM). The SCM is considered the "main" clock in our body and will set off a cascade of events telling our bodies to wake. One such event is the activation of the Hypothalamic Pituitary Adrenal (HPA) axis. The activation of the HPA axis will cause cortisol production. Cortisol is our daytime hormone and works inversely with melatonin; when one is up, the other should be down. Cortisol is highest just after waking, a process called the Cortisol Awakening Response (CAR), and will then begin to decline until night comes, when it should be its lowest. This is when melatonin begins to be released.

Women seem to have higher levels than men, but not by much. Melatonin production is absent in infants, with a rhythm not forming until two to three months of age. Levels begin to decline in the late third decade of life, playing a role in sleep issues in adults.

What is Melatonin's Role in The Body?

In addition to affecting sleep, as discussed above, melatonin can also affect menstrual cycles, neurodegenerative disorders, and aging.

Menstrual Cycles

Melatonin has been shown to affect the start of menstruation and the length of the cycle. If melatonin levels change, this can cause either a delayed or missed period.

Neurodegenerative disorders

Melatonin can prevent the loss of function of brain cells, called neurons. This loss of function is called neurodegeneration and is seen in conditions such as Parkinson's and Alzheimer's disease

Aging

Rapid signs of aging were seen in people who had their pineal glands removed (pinealectomy). Since the pineal gland's primary job is to make melatonin, researchers believe it plays a role in the aging process.  

What are some Evidence Based Health Benefits of Melatonin?

Melatonin may be indicated for the following conditions:

Delayed Sleep Wake Disorder (DSWD)

People with DSWD have trouble falling asleep at night and waking up in the morning. Diagnosed by assessing sleep timing, circadian rhythms are usually delayed by two or more hours in these patients; bedtime is usually between 2-6 AM, and waking time is between 10 AM-1 PM.

Shift Work

Shift workers are more likely to have cardiovascular, gastrointestinal, and psychological diseases, as well as cancer, diabetes, and reproductive issues. In these patients, melatonin may help to increase sleep duration and quality.

Jet Lag

Jet lag occurs when traveling between different time zones. The body's circadian clock has difficulty adjusting to the new time zone, and symptoms of difficulty falling asleep and waking up early, fatigue, difficulty focusing, mood changes, and stomach problems can occur. The severity of symptoms is generally related to the distance traveled; the father traveled, the worse the symptoms. Doctors recommend taking melatonin before the ideal bedtime prior to travel and continuing a few days after arrival.

What Are The Side Effects Of Melatonin To Be Aware Of?

Common side effects of melatonin include headaches, nausea, dizziness, and daytime sleepiness. Less common side effects include gastrointestinal problems such as constipation, diarrhea, stomach cramps, mood swings, increased risk of falls and seizures, vivid dreams and nightmares, and reduced alertness and confusion.

Since melatonin can induce sleep and drowsiness, it should not be taken within five hours of driving.

Melatonin Imbalances To Be Aware Of

High levels of melatonin, referred to as hypermelatoninemia, are usually due to over-supplementation. However, the following conditions can also cause high melatonin levels: pituitary tumors, Polycystic Ovarian Syndrome (PCOS), anorexia nervosa, hypogonadism, spontaneous hypothermia hyperhidrosis, and Rabson-Mendenhall syndrome.

Melatonin deficiency, referred to as hypomelatoninemia, is seen primarily in congenital malformations but also in shift work, aging, neurodegenerative diseases, genetic diseases, and as a result of surgeries involving the sympathetic nervous system. Medications, including beta-blockers, calcium channel blockers, and ACE inhibitors, can also cause hypomelatoninemia.

How to Test Melatonin Vitamin Levels

Serum

Melatonin does not last long in the blood, and therefore it may be difficult to assess levels unless the timing is just right. Therefore, melatonin is more commonly assessed via saliva or urine.  

Saliva

The Melatonin Profile provides a snapshot of the sleep/wake cycle during a one day period and is recommended for those experiencing sleep disturbances.

Urine

Urinary testing looks at metabolites or breakdown products of melatonin in the urine. Samples can also be calculated to represent the amount of melatonin in the serum or blood. Melatonin is part of the DUTCH test by Precision Analytical. This test is useful in that it has an entire section on the HPA axis, including measurements of cortisol, cortisone, and DHEA.

Another option is The Sleep Balance Profile from ZRT which measures the diurnal patterns of melatonin, cortisol, and cortisone to assess the sleep/wake cycle.

How to Make Sure You are Producing Enough Melatonin

Food

Melatonin is found naturally in foods. The best food sources of melatonin are tart cherries, goji berries, eggs, milk, fish, and nuts.  

Exercise

Exercise can increase the amount of melatonin in a phase shift manner, meaning exercising doesn't immediately increase melatonin levels. Rather, it causes an increase at night when melatonin should be released.

Supplement

Dosages of melatonin vary from 0.3-10mg, although it seems smaller doses are more effective. The body's natural production of melatonin is around 0.3mg; thus, most doctors recommend a dosage between 0.5 and 3mg. Some studies suggest that the timing of melatonin supplementation, which will vary depending on the person and problem, is more important than the dose.

Morning light

Stepping outside in the morning, even on cloudy days, for 15-30 minutes can help reset the circadian rhythm and potentially aid in the natural production of melatonin at night.

Avoiding Light at Night

Light at night, when melatonin should be released, can significantly suppress its release, depending on how bright the light is and the duration of exposure. Additionally, cortisol's sensitivity to light is heightened at night, which would again lead to the suppression of melatonin.

Bright light therapy

Bright light therapy uses light to induce the production of cortisol in the morning, aiding in resetting the circadian rhythm. The light, although artificial, will have different bandwidths and lux, which is a measurement of how much light falls on your eyes. These lights are void of harmful UV rays. Bright light therapy can come in the form of light boxes, desk lamps, light visors, and dawn simulators.

Summary

Melatonin is an important hormone that plays a critical role in sleep and circadian rhythm. Melatonin testing can be helpful in assessing the circadian rhythm and the HPA axis and can function as a useful tool to alleviate fatigue and sleep-related disorders.