Melatonin Testing

Written by Mark Newman, President of Precision Analytical, Inc. 

Melatonin Facts…

Melatonin is a hormone produced in the pineal gland in response to light. Therefore, among many things, it regulates the sleep-wake cycle or circadian rhythm. Some melatonin is also made in the gut. As light fades in the evening, the pineal gland begins to produce melatonin to induce a normal sleep pattern. Melatonin is important because it is a potent antioxidant, immune system modulator, promoter of growth hormone production and can improve those affected by seasonal affective disorder (SAD). Therefore, low levels of melatonin can cause sleep issues (falling or staying asleep), weaker immune systems, mood changes, fatigue and low growth hormone.

Avoiding the bright light of phones, computers, television, and tablets before bed then sleeping in total darkness is critical to healthy natural production of melatonin. In addition, high stress, particularly elevated cortisol at night, is suppressive to the pineal gland causing lower levels of melatonin. On the other hand, slightly elevated levels may be due to the supplements tryptophan or 5HTP (as both promote serotonin and serotonin can convert into melatonin) and SSRI’s (particularly fluoxetine) or MAO inhibiting medications.

Testing Melatonin (Using Dried Urine)

In urine we measure 6-Hydroxymelatonin-sulfate. Studies have shown that monitoring this metabolite in the urine, collected upon waking, correlates beautifully to nighttime production of melatonin. However, the test does not work when taking oral melatonin as the urine is flooded with gut metabolites. These metabolites do NOT represent circulating melatonin levels.

Testing for melatonin is very important, yet results depend on whether or not your patient is sleeping and if they take melatonin to sleep. Since we are most concerned with cortisol results, the DUTCH testing instructions no longer ask patients to discontinue melatonin supplementation.

(DUTCH, Dried Urine Test for Comprehensive Hormones is a urine hormone test that measures the daily up-and-down pattern of free cortisol along with cortisol, androgen, estrogen and progesterone metabolites along with melatonin. See this video for more information.)

There is limited value in getting off of melatonin supplementation for a true baseline value. Doing so may disrupt “normal” sleep patterns, resulting in cortisol levels that are different than the norm.

Not on Melatonin Supplementation?

If the patient does not take melatonin supplements to sleep, do not have them start melatonin supplementation until the test, in order to accurately assess the patient’s baseline levels. If warranted, they may start melatonin supplementation after testing.

For the most accurate assessment, you will want your patients to avoid the following foods that may contain melatonin the day of testing: bananas, pineapple, citrus fruit, tart sour cherries, walnuts, corn, rice, and peanuts.

Is the Patient On Melatonin Supplementation for Insomnia?

Obtaining accurate cortisol measurements is the goal, so we suggest that if your patient cannot sleep well without melatonin supplements and takes them regularly, they should continue to take the melatonin as usual before bed. Doing so will create a high level of metabolites on testing results; however, the patient will sleep normally which will result in normal-for-them cortisol levels. In this scenario, melatonin results will NOT be helpful in assessing the melatonin therapy.

On Melatonin Supplementation, But Want a Baseline?

If you want to know melatonin and cortisol levels without supplementation, we suggest having the patient stop the melatonin supplement for 2-3 days prior to testing so that their melatonin levels will go back to baseline.

Limited data implies that by skipping melatonin supplementation the day of the test, baseline levels can be seen. We suggest giving at least one more skipped day ensure accurate results. Understand that doing so may cause insomnia, which could interfere with cortisol testing results.

Read the original blog here or learn more about Precision Analytical and DUTCH (dried urine test for comprehensive hormones).

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