Melatonin
A blood test that measures melatonin levels to assess sleep-wake cycles and circadian rhythm function.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
What this test measures
Melatonin is a hormone produced by the pineal gland, a small structure deep in the brain, that serves as the body's primary signal for darkness and sleep timing. When light levels drop in the evening, the pineal gland begins releasing melatonin into the bloodstream, communicating to the body's internal clock that nighttime has arrived and triggering physiological processes that prepare the body for sleep.
Melatonin follows a pronounced circadian rhythm. Daytime levels are minimal, typically below 0.02 ng/mL. Secretion begins to rise roughly two hours before habitual bedtime, climbs through the night, and peaks between approximately 3 and 4 AM before declining again toward morning. This test measures the blood concentration of melatonin and is used to evaluate whether the body's natural sleep-wake cycle is functioning as expected. It can help healthcare providers investigate circadian rhythm disruptions, persistent insomnia, or conditions in which melatonin production may be abnormally high or low for the time of day.
Who should consider this test
You might consider this test if you are experiencing any of the following:
- Individuals experiencing chronic insomnia or difficulty falling asleep despite good sleep hygiene practices may benefit from this test.
- Those with suspected circadian rhythm sleep disorders, such as delayed sleep phase syndrome or shift work sleep disorder, should consider melatonin testing.
- People who frequently travel across time zones and struggle with persistent jet lag symptoms may find this test helpful.
- Individuals with autism spectrum disorder, ADHD, or other neurodevelopmental conditions often associated with sleep disturbances should consider testing.
- Those with seasonal affective disorder (SAD) or symptoms that worsen during darker months may benefit from evaluating their melatonin levels.
What to expect
Preparation
No special preparation is required for this test. However, timing of the blood draw is important as melatonin levels vary dramatically throughout the day. Your healthcare provider will advise on the optimal collection time based on your specific symptoms.
Sample Type
A standard blood draw is performed, typically from a vein in the arm. The procedure takes just a few minutes and requires only a small amount of blood.
Collection
During your visit to the lab, a trained phlebotomist will clean the collection site and use a sterile needle to draw blood into a specialized tube. The sample is then labeled and prepared for laboratory analysis.
Turnaround
Results are typically available within 3 to 5 business days after the sample reaches the laboratory. You will receive your results securely through your patient portal.
Understanding your results
Normal melatonin levels generally range from roughly 0.02 to 0.2 ng/mL, but this range is meaningful only when paired with the time of day the blood was drawn. Nighttime levels (approximately 18 to 197 pg/mL) are naturally many times higher than daytime levels (approximately 3 to 80 pg/mL), so a result that appears elevated on a morning draw might be entirely normal for a nighttime sample. Reference ranges vary by laboratory. Healthcare providers interpret melatonin results in the context of collection timing, reported sleep patterns, light exposure habits, and any medications or supplements that may influence melatonin production.
| Population | Reference Range | Notes |
|---|---|---|
| Adults (daytime collection) | 0.02-0.2 ng/mL | May vary significantly based on time of collection and age |
| Adults (nighttime peak) | 18-197 pg/mL | Peak levels typically occur around 3-4 AM |
Reference ranges may vary by laboratory and individual factors. Results should be interpreted by a healthcare provider in the context of your overall health.
What does a “Low” result mean?
Low melatonin levels may be associated with high stress, particularly elevated cortisol at night, which can suppress the pineal gland and reduce melatonin production. Reduced melatonin secretion has been observed in certain psychiatric conditions, including schizophrenia and neurocognitive disorders, often due to a smaller pineal gland volume and increased calcification. Dysfunction in melatonin production has been associated with various conditions affecting the nervous system, including Alzheimer's disease, Parkinson's disease, depression, and cardiovascular disorders. Low melatonin is particularly common in pediatric populations with neurodevelopmental disorders, including autism spectrum disorder and neurogenetic disorders, which may explain abnormal sleep-wake cycle development. Multiple disorders associated with intellectual dysfunction have been associated with decreased melatonin production, and supplementation may help improve sleep and stabilize circadian rhythms.
What does a “High” result mean?
Elevated melatonin levels may be associated with sleep disturbances, difficulty waking in the morning, and feelings of lethargy during the day. Higher melatonin production is often noted during darker months of autumn and winter and may contribute to seasonal affective disorder. High levels may also be linked to inhibition of ovulation in women, decreased body temperature, and have been noted during the manic phase of bipolar mood disorder. Certain medications can affect melatonin levels. Many antidepressant drugs may stimulate melatonin production, including fluvoxamine, desipramine, and most MAO inhibitors, while Prozac may lower melatonin levels. If melatonin is inappropriately elevated during daytime hours, it may suggest a disrupted circadian rhythm that could benefit from light therapy or other interventions.
Privacy & confidentiality
All melatonin test results are kept strictly confidential and protected under HIPAA regulations. Your results will not be shared with insurance companies or added to your medical records without your explicit consent. No doctor visit is required to order this test, giving you complete control over your health information.
Frequently asked questions
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Last reviewed: April 2026
CPT Code: 80375
This test may not be available in: NY, NJ, RI
This page is for informational purposes only and does not constitute medical advice. Always consult with a healthcare provider regarding any health concerns. LevelPanel does not diagnose, treat, or prescribe.
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LevelPanel has no business or affiliate relationship with Quest or LabCorp. These links are provided as a public service.
Lab testing services linked from this site are not available to residents of Alaska, Arizona, or Hawaii, unless otherwise noted on the lab's own website.
This publication is not intended to solicit the purchase of laboratory testing from any individual consumer.
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